2024 Vol. 41, No. 8
2024, 41(8): 3839-3865.
doi: 10.13801/j.cnki.fhclxb.20240015.003
Abstract:
With high theoretical specific capacity, high safety, low cost, and sufficient raw material sources, aluminum-ion batteries have been regarded as potential alternatives to lithium-ion batteries. However, the shortcomings of the inherent characteristics of the cathode material have greatly limited the further development of aluminum-ion batteries. In this paper, the important role of cathode materials in the application filed of aluminum ion battery was summarized, the mechanism of action and research progress of aluminum ion electrode materials were reviewed, and the effects of various cathode materials such as carbon-based, transition metal oxides and sulfides, organic materials and metal-organic skeletal compounds on the electrochemical performance of aluminum ion batteries were summarize. Finally, the problems that need to be solved urgently in the field of positive electrode materials for aluminum ion batteries are discussed, and the future development direction of positive electrode materials for aluminum ion batteries is proposed.
With high theoretical specific capacity, high safety, low cost, and sufficient raw material sources, aluminum-ion batteries have been regarded as potential alternatives to lithium-ion batteries. However, the shortcomings of the inherent characteristics of the cathode material have greatly limited the further development of aluminum-ion batteries. In this paper, the important role of cathode materials in the application filed of aluminum ion battery was summarized, the mechanism of action and research progress of aluminum ion electrode materials were reviewed, and the effects of various cathode materials such as carbon-based, transition metal oxides and sulfides, organic materials and metal-organic skeletal compounds on the electrochemical performance of aluminum ion batteries were summarize. Finally, the problems that need to be solved urgently in the field of positive electrode materials for aluminum ion batteries are discussed, and the future development direction of positive electrode materials for aluminum ion batteries is proposed.
2024, 41(8): 3866-3882.
doi: 10.13801/j.cnki.fhclxb.20240407.005
Abstract:
With the rapid advancement of modern science and technology, the widespread adoption of electronic information devices has significantly enhanced the quality of human life. However, security issues such as electromagnetic interference and leakage are arose with this progress. These issues become particularly pronounced in the field of national defense and military technology, where the improvement and upgrading of radar testing technologies pose substantial threats to the survivability of weaponry systems. Consequently, there is an urgent need to develop high-performance electromagnetic absorption materials to suppress electromagnetic interference and radiation, thereby preventing information leakage. This article takes the application of absorption materials and absorption structures as its starting point, systematically organizing the electromagnetic wave loss mechanism of various absorption materials. Simultaneously, it explores the primary means of application for absorption structures. Building upon this foundation, the current state and future trends of research on absorption materials and structures are elucidated. Furthermore, a comprehensive analysis of the advantages and shortcomings inherent in current research and development is undertaken, culminating in the identification of key scientific issues that the field of absorption must address in the future. In response to the current inadequacies in the integration of absorption materials and structural functionality, pivotal recommendations regarding future research directions are proposed. The methods discussed and strategies put forth herein are poised to provide valuable guidance for innovative designs in the realm of absorption-bearing structures in the future.
With the rapid advancement of modern science and technology, the widespread adoption of electronic information devices has significantly enhanced the quality of human life. However, security issues such as electromagnetic interference and leakage are arose with this progress. These issues become particularly pronounced in the field of national defense and military technology, where the improvement and upgrading of radar testing technologies pose substantial threats to the survivability of weaponry systems. Consequently, there is an urgent need to develop high-performance electromagnetic absorption materials to suppress electromagnetic interference and radiation, thereby preventing information leakage. This article takes the application of absorption materials and absorption structures as its starting point, systematically organizing the electromagnetic wave loss mechanism of various absorption materials. Simultaneously, it explores the primary means of application for absorption structures. Building upon this foundation, the current state and future trends of research on absorption materials and structures are elucidated. Furthermore, a comprehensive analysis of the advantages and shortcomings inherent in current research and development is undertaken, culminating in the identification of key scientific issues that the field of absorption must address in the future. In response to the current inadequacies in the integration of absorption materials and structural functionality, pivotal recommendations regarding future research directions are proposed. The methods discussed and strategies put forth herein are poised to provide valuable guidance for innovative designs in the realm of absorption-bearing structures in the future.
2024, 41(8): 3883-3896.
doi: 10.13801/j.cnki.fhclxb.20240229.003
Abstract:
In the field of anti-corrosion, epoxy resin anti-corrosion composite coating is an excellent material to prevent metal corrosion. The epoxy coating forms a barrier between the metal and the corrosive ions, but the anti-corrosion effect of the epoxy resin does not last long during curing due to mechanical breakage and the formation of micropores. Three strategies for enhancing the anticorrosive properties of epoxy resin are introduced in this paper, namely nanoparticle modification, micro/nano container modification, and bio-based material modification. The research progress of epoxy resin anticorrosive composite coating modification is reviewed, and the future development direction of epoxy resin anticorrosive composite coating is prospected. In the future, a green epoxy anticorrosive composite coating with intelligent self-warning and self-repair, multi-function and cost-effective should be developed.
In the field of anti-corrosion, epoxy resin anti-corrosion composite coating is an excellent material to prevent metal corrosion. The epoxy coating forms a barrier between the metal and the corrosive ions, but the anti-corrosion effect of the epoxy resin does not last long during curing due to mechanical breakage and the formation of micropores. Three strategies for enhancing the anticorrosive properties of epoxy resin are introduced in this paper, namely nanoparticle modification, micro/nano container modification, and bio-based material modification. The research progress of epoxy resin anticorrosive composite coating modification is reviewed, and the future development direction of epoxy resin anticorrosive composite coating is prospected. In the future, a green epoxy anticorrosive composite coating with intelligent self-warning and self-repair, multi-function and cost-effective should be developed.
2024, 41(8): 3897-3909.
doi: 10.13801/j.cnki.fhclxb.20240412.001
Abstract:
Plant fiber, as a biobased material in nature, the development and applications of green and environmentally friendly materials and applications have attracted much attention. Plant-based micro and nanofibers have excellent characteristics such as high specific surface area, high strength, high modulus, and so on. It has great potential to replace some non-biodegradable plastic materials and products by using it to construct green and environmentally friendly structural materials. In this review article, the research progress of plant fiber self-bonding molding environmentally friendly materials is summarized and presented. The preparation process and performance of plant micro-fiber molding materials, plant nanocellulose structural materials and plant micro and nanofiber structural materials are mainly discussed. The key research directions of plant fiber self-bonding molding environmentally friendly materials in the future are prospected in order to promote the development and application and of plant fiber in structural materials and provide some reference.
Plant fiber, as a biobased material in nature, the development and applications of green and environmentally friendly materials and applications have attracted much attention. Plant-based micro and nanofibers have excellent characteristics such as high specific surface area, high strength, high modulus, and so on. It has great potential to replace some non-biodegradable plastic materials and products by using it to construct green and environmentally friendly structural materials. In this review article, the research progress of plant fiber self-bonding molding environmentally friendly materials is summarized and presented. The preparation process and performance of plant micro-fiber molding materials, plant nanocellulose structural materials and plant micro and nanofiber structural materials are mainly discussed. The key research directions of plant fiber self-bonding molding environmentally friendly materials in the future are prospected in order to promote the development and application and of plant fiber in structural materials and provide some reference.
2024, 41(8): 3910-3934.
doi: 10.13801/j.cnki.fhclxb.20240304.005
Abstract:
In order to solve the electromagnetic wave pollution caused by electronic information technology, carbon-based composite absorbing materials have received extensive attention. Biomass-derived carbon composites not only have excellent electromagnetic wave absorption ability, but also have the advantages of low density, wide source and low cost. Firstly, the preparation method and process of biomass derived carbon are described. Secondly, the structural and morphological characteristics of three kinds of biomass-derived carbon, including plant kingdom, fungus kingdom and protista kingdom, were systematically summarized, and the research results of biomass-derived carbon-based composite absorbing materials in recent years were summarized. Then, the structural morphology and electromagnetic wave absorption properties of different kinds of absorbing materials are compared, and the absorbing mechanism of various materials is analyzed. Finally, the current wave absorbing properties and disadvantages of biomass-derived carbon matrix composites are analyzed, and the future development direction is prospected. This paper provides comprehensive induction, classification, analysis and theoretical support for promoting the research of non-animal biomass derived carbon composite absorbing materials, and provides ideas for its future development.
In order to solve the electromagnetic wave pollution caused by electronic information technology, carbon-based composite absorbing materials have received extensive attention. Biomass-derived carbon composites not only have excellent electromagnetic wave absorption ability, but also have the advantages of low density, wide source and low cost. Firstly, the preparation method and process of biomass derived carbon are described. Secondly, the structural and morphological characteristics of three kinds of biomass-derived carbon, including plant kingdom, fungus kingdom and protista kingdom, were systematically summarized, and the research results of biomass-derived carbon-based composite absorbing materials in recent years were summarized. Then, the structural morphology and electromagnetic wave absorption properties of different kinds of absorbing materials are compared, and the absorbing mechanism of various materials is analyzed. Finally, the current wave absorbing properties and disadvantages of biomass-derived carbon matrix composites are analyzed, and the future development direction is prospected. This paper provides comprehensive induction, classification, analysis and theoretical support for promoting the research of non-animal biomass derived carbon composite absorbing materials, and provides ideas for its future development.
Research progress on the application of lignin-based functional materials in barrier packaging paper
2024, 41(8): 3935-3949.
doi: 10.13801/j.cnki.fhclxb.20240314.004
Abstract:
With the gradual depletion of petroleum resources, bio-based barrier packaging materials have garnered growing attention as an eco-friendly alternative to conventional petroleum-based plastic packaging. Lignin, the second most abundant natural polymer and the only renewable resource rich in repetitive benzene ring structural units, possesses biodegradability, biocompatibility and excellent processability. Currently, the majority of lignin is still disposed of through incineration as industrial by-products, resulting in limited utilization and low added value. Due to its unique chemical structure, water resistance, solvent resistance, aging resistance, and UV resistance, lignin exhibits significant potential in the development of bio-based barrier materials. However, further consideration is required regarding the structural characteristics of lignin, its multifaceted barrier properties in material applications, the establishment of structure-property relationships, and exploration of diverse application scenarios. Therefore, the present review provides a systematic and comprehensive review of the application of lignin-based functional materials in barrier packaging paper. Firstly, the structure and origin of lignin are briefly elucidated. A comprehensive overview of the current status of the application of lignin-based functional materials in barrier packaging papers is then provided, with particular emphasis on the advances in the use of lignin-based functional materials for water, gas, oil, ultraviolet radiation and flame retardancy properties in packaging paper. Finally, the primary challenges and future prospects for the development of lignin-based functional materials in barrier packaging paper applications are discussed. This review will provide a theoretical foundation for the utilization of lignin-based functional materials in the production of paper with single or multiple barrier properties, thereby providing practical significance for the industrial-scale manufacturing of value-added products derived from lignin.
With the gradual depletion of petroleum resources, bio-based barrier packaging materials have garnered growing attention as an eco-friendly alternative to conventional petroleum-based plastic packaging. Lignin, the second most abundant natural polymer and the only renewable resource rich in repetitive benzene ring structural units, possesses biodegradability, biocompatibility and excellent processability. Currently, the majority of lignin is still disposed of through incineration as industrial by-products, resulting in limited utilization and low added value. Due to its unique chemical structure, water resistance, solvent resistance, aging resistance, and UV resistance, lignin exhibits significant potential in the development of bio-based barrier materials. However, further consideration is required regarding the structural characteristics of lignin, its multifaceted barrier properties in material applications, the establishment of structure-property relationships, and exploration of diverse application scenarios. Therefore, the present review provides a systematic and comprehensive review of the application of lignin-based functional materials in barrier packaging paper. Firstly, the structure and origin of lignin are briefly elucidated. A comprehensive overview of the current status of the application of lignin-based functional materials in barrier packaging papers is then provided, with particular emphasis on the advances in the use of lignin-based functional materials for water, gas, oil, ultraviolet radiation and flame retardancy properties in packaging paper. Finally, the primary challenges and future prospects for the development of lignin-based functional materials in barrier packaging paper applications are discussed. This review will provide a theoretical foundation for the utilization of lignin-based functional materials in the production of paper with single or multiple barrier properties, thereby providing practical significance for the industrial-scale manufacturing of value-added products derived from lignin.
2024, 41(8): 3950-3967.
doi: 10.13801/j.cnki.fhclxb.20240314.003
Abstract:
Superhydrophobic coatings with excellent corrosion resistance, self-cleaning, anti-fog, drag reduction, or icing resistance have been paid more and more attention due to their applications in the engineering and coatings industry. In addition, the application of superhydrophobic coatings can be greatly expanded by introducing functional fillers such as heat insulation, anti-icing, flame retardant, and anti-corrosion into the coating. In this paper, the mechanism of superhydrophobic coating is first reviewed, and the classical wetting theory of superhydrophobic coating is further described, including Young's model, Wenzel model, and Cassie-Baxter model. The characteristics of different preparation methods of superhydrophobic coatings are compared, subsequently. Finally, the main problems existing in the development of superhydrophobic coatings are pointed out by introducing the research progress of multifunctional superhydrophobic coatings, and the development direction of superhydrophobic coatings is proposed.
Superhydrophobic coatings with excellent corrosion resistance, self-cleaning, anti-fog, drag reduction, or icing resistance have been paid more and more attention due to their applications in the engineering and coatings industry. In addition, the application of superhydrophobic coatings can be greatly expanded by introducing functional fillers such as heat insulation, anti-icing, flame retardant, and anti-corrosion into the coating. In this paper, the mechanism of superhydrophobic coating is first reviewed, and the classical wetting theory of superhydrophobic coating is further described, including Young's model, Wenzel model, and Cassie-Baxter model. The characteristics of different preparation methods of superhydrophobic coatings are compared, subsequently. Finally, the main problems existing in the development of superhydrophobic coatings are pointed out by introducing the research progress of multifunctional superhydrophobic coatings, and the development direction of superhydrophobic coatings is proposed.
2024, 41(8): 3968-3986.
doi: 10.13801/j.cnki.fhclxb.20240314.002
Abstract:
Phase change materials (PCM) can bridge the gap between heat supply and demand in time and space, and are widely used in heat storage and thermal management systems. However, a single PCM has defects such as easy leakage, volume change, phase separation and corrosion. Therefore, microencapsulated PCM to prepare microencapsulated composite phase change materials (MEPCM) by microencapsulated technology and enhanced by different nano-fillers can not only effectively overcome the above defects, but also improve its thermal performance and operational stability. This paper first introduces the selection principle of the core material and shell of MEPCM, the composition and preparation strategy of MEPCM, focuses on the influence of nano-fillers of different dimensions on the thermal properties of MEPCM, and summarizes the application of MEPCM in the fields of construction, textiles and thermal management. The future research directions and challenges of nano-fillers in rational design and construction of high-performance MEPCM are also discussed.
Phase change materials (PCM) can bridge the gap between heat supply and demand in time and space, and are widely used in heat storage and thermal management systems. However, a single PCM has defects such as easy leakage, volume change, phase separation and corrosion. Therefore, microencapsulated PCM to prepare microencapsulated composite phase change materials (MEPCM) by microencapsulated technology and enhanced by different nano-fillers can not only effectively overcome the above defects, but also improve its thermal performance and operational stability. This paper first introduces the selection principle of the core material and shell of MEPCM, the composition and preparation strategy of MEPCM, focuses on the influence of nano-fillers of different dimensions on the thermal properties of MEPCM, and summarizes the application of MEPCM in the fields of construction, textiles and thermal management. The future research directions and challenges of nano-fillers in rational design and construction of high-performance MEPCM are also discussed.
2024, 41(8): 3987-4003.
doi: 10.13801/j.cnki.fhclxb.20240321.001
Abstract:
Ceramic-matrix composites (CMCs) are typical difficult-to-machine materials, which possess great hardness—second only to diamond and cubic boron nitride—and anisotropy. The fundamental structure of CMCs parts in aeroengines is the embedded holes (air film holes, etc.) in the hot-section components. These holes are crucial for the preparation and molding of CMCs components as well as the service life. The categorization of embedded holes in hot-section CMCs components is given in this paper. The processing principles, process characteristics, selection of process parameters, characteristics of the processing defects and formation mechanism, etc., are all determined by analyzing the methods used for processing CMCs embedded holes, including conventional mechanical processing methods, ultrasonic vibration-assisted processing methods, laser processing methods, etc. Recommendations for the processing of CMCs embedded holes with different diameters and depth-to-diameter ratios are also provided.
Ceramic-matrix composites (CMCs) are typical difficult-to-machine materials, which possess great hardness—second only to diamond and cubic boron nitride—and anisotropy. The fundamental structure of CMCs parts in aeroengines is the embedded holes (air film holes, etc.) in the hot-section components. These holes are crucial for the preparation and molding of CMCs components as well as the service life. The categorization of embedded holes in hot-section CMCs components is given in this paper. The processing principles, process characteristics, selection of process parameters, characteristics of the processing defects and formation mechanism, etc., are all determined by analyzing the methods used for processing CMCs embedded holes, including conventional mechanical processing methods, ultrasonic vibration-assisted processing methods, laser processing methods, etc. Recommendations for the processing of CMCs embedded holes with different diameters and depth-to-diameter ratios are also provided.
2024, 41(8): 4004-4025.
doi: 10.13801/j.cnki.fhclxb.20240315.001
Abstract:
The inverse opal structure (IO) is a typical spatial structure of photonic crystals. In addition to the interconnected, highly regular, and orderly homoporous structure, IO also has the properties of photonic crystals, including the slow light effect, multiple scattering effects, amplified photon absorption and emission characteristics. In recent years, applications for IO have included homoporous membranes, photonic inks, battery electrodes, sensors, etc. In this paper, we first briefly describe the construction strategy of IO, which is divided into the "three-step method" and "two-step method". Then, the research progress of IO in water treatment fields was summarized in detail, including filtration and screening, efficient adsorption, catalytic degradation, and water quality detection. Finally, the existing limitations and future development trends of IO materials in water treatment fields were elaborated and prospected.
The inverse opal structure (IO) is a typical spatial structure of photonic crystals. In addition to the interconnected, highly regular, and orderly homoporous structure, IO also has the properties of photonic crystals, including the slow light effect, multiple scattering effects, amplified photon absorption and emission characteristics. In recent years, applications for IO have included homoporous membranes, photonic inks, battery electrodes, sensors, etc. In this paper, we first briefly describe the construction strategy of IO, which is divided into the "three-step method" and "two-step method". Then, the research progress of IO in water treatment fields was summarized in detail, including filtration and screening, efficient adsorption, catalytic degradation, and water quality detection. Finally, the existing limitations and future development trends of IO materials in water treatment fields were elaborated and prospected.
2024, 41(8): 4026-4038.
doi: 10.13801/j.cnki.fhclxb.20231220.002
Abstract:
Photothermal tumor therapy with second near-infrared (NIR-II,1000 -1350 nm) phototriggered photothermal agents is a promising emerging method of tumor therapy. Transition metal carbides, nitrides, and carbonitridges compounds (MXenes) have advantages such as ultra-thin layered structure, unique electronic properties, large specific surface area, high photothermal conversion efficiency, good hydrophilicity, and easy surface functionalization, making them suitable as photothermal agents for tumor photothermal therapy. This review introduces the advantages of NIR-II photothermal therapy, summarizes the photothermal performance of MXenes and the stability of MXenes colloidal solution. At the same time, the research progress of MXenes in NIR-II tumor photothermal therapy was discussed, and the challenges and opportunities faced in the future development of this field were elaborated.
Photothermal tumor therapy with second near-infrared (NIR-II,
2024, 41(8): 4039-4057.
doi: 10.13801/j.cnki.fhclxb.20231117.002
Abstract:
To meet the extreme thermal protection and load-bearing requirement of aerospace vehicle, three-dimensional orthogonal fiber reinforced nanoporous resin composites (3DIPC) have been prepared using three-dimensional quartz fiber preform as reinforcement and high-strength nanoporous phenolic resin as matrix. The as-prepared 3DIPC exhibit a mid-density of ~1.46 g·cm−3, low room-temperature thermal conductivity (<0.30 W·(m·K)−1), low linear ablation rate (~0.15 mm·s−1) and excellent mechanical properties with tensile strength >400 MPa, compressive strength >390 MPa, bending strength >300 MPa and interlaminar shear strength >30 MPa. By adjusting the yarn fineness in different directions, the effects of meso-structure variations in fiber preforms on the mechanical properties of 3DIPC were systematically studied. The results show increasing the fineness of the Z yarn can enhance the compressive modulus and interlaminar shear strength of composite materials, but it leads to a deterioration of tensile properties and compressive strength. Increasing the fineness of the warp yarn can improve the tensile and bending properties in the warp direction, but the tensile and flexural properties in the weft direction will be reduced. Finally, a mesoscale finite element model incorporating both surface and internal structures was established based on the actual morphology of 3DIPC. Combining with the progressive damage model of the composite material, the tensile failure behavior of the 3DIPC was simulated using the finite element software ABAQUS. The results show that the damage in 3DIPC initiates at the matrix of yarns and propagates to pure matrix and the fibers of yarns as the strain increases. The failure of 3DIPC under tensile loading in the warp and weft direction is dominated by the fracture of fibers of warp and weft yarns, respectively. Furthermore, the fracture of fibers of surface-Z yarns and surface-weft yarns is the primary cause of early-stage damage in 3DIPC under tensile loading in the weft direction.
To meet the extreme thermal protection and load-bearing requirement of aerospace vehicle, three-dimensional orthogonal fiber reinforced nanoporous resin composites (3DIPC) have been prepared using three-dimensional quartz fiber preform as reinforcement and high-strength nanoporous phenolic resin as matrix. The as-prepared 3DIPC exhibit a mid-density of ~1.46 g·cm−3, low room-temperature thermal conductivity (<0.30 W·(m·K)−1), low linear ablation rate (~0.15 mm·s−1) and excellent mechanical properties with tensile strength >400 MPa, compressive strength >390 MPa, bending strength >300 MPa and interlaminar shear strength >30 MPa. By adjusting the yarn fineness in different directions, the effects of meso-structure variations in fiber preforms on the mechanical properties of 3DIPC were systematically studied. The results show increasing the fineness of the Z yarn can enhance the compressive modulus and interlaminar shear strength of composite materials, but it leads to a deterioration of tensile properties and compressive strength. Increasing the fineness of the warp yarn can improve the tensile and bending properties in the warp direction, but the tensile and flexural properties in the weft direction will be reduced. Finally, a mesoscale finite element model incorporating both surface and internal structures was established based on the actual morphology of 3DIPC. Combining with the progressive damage model of the composite material, the tensile failure behavior of the 3DIPC was simulated using the finite element software ABAQUS. The results show that the damage in 3DIPC initiates at the matrix of yarns and propagates to pure matrix and the fibers of yarns as the strain increases. The failure of 3DIPC under tensile loading in the warp and weft direction is dominated by the fracture of fibers of warp and weft yarns, respectively. Furthermore, the fracture of fibers of surface-Z yarns and surface-weft yarns is the primary cause of early-stage damage in 3DIPC under tensile loading in the weft direction.
2024, 41(8): 4058-4072.
doi: 10.13801/j.cnki.fhclxb.20231218.004
Abstract:
Vitrimer can undergo plastic deformation while maintaining a cross-linked state, which means that traditional thermosetting resins have the ability to undergo secondary thermal processing and molding, which will effectively reduce scrap rates and reduce waste from the beginning. The plastic deformation of vitrimer can also endow item self-healing ability and extended its service life, and so contribute to environmental protection and emission reduction. In the paper stannous iso-octanoate as a catalyst and phenolic resin as a modifier was used to prepare anhydride cured epoxy vitrimer materials. The research results indicate that the increase in catalyst content could make the system cure more completely, so there is a certain improvement in the bending strength of the material, up to 87.5 MPa. With introduction of phenolic resin, the bending strength increases from 87.5 MPa before modification to 126.9 MPa, and the tensile strength reaches 63.3 MPa. When the amount of phenolic resin added is too high, the crosslinking density of the material decreases, and the mechanical properties of the material show a downward trend. The study on the relaxation behavior of the epoxy vitrimer system cured with pure anhydride shows that increasing the catalyst content reduces the relaxation time of the materials, but the post curing reaction at high temperature could inhibit the relaxation process and suppress the self-welding strength. The stress relaxation of epoxy vitrimer material modified with phenolic resin is significantly faster than that of epoxy vitrimer system cured with pure anhydride. The relaxation of the samples with 10mol% catalyst shows a sudden change, and there is a significant acceleration when the temperature rises to 190℃, and the introduction of phenolic resin could advance the sudden change temperature Ts to 180℃. Under no pressure conditions, scratches are repaired. The tensile shear strength and scratches repair effect of the samples repaired above Ts are significantly improved. Compared to samples without phenolic resin, phenolic modified samples could be repaired better. Catalyst have a significant impact on the repair strength and repair speed of the samples.
Vitrimer can undergo plastic deformation while maintaining a cross-linked state, which means that traditional thermosetting resins have the ability to undergo secondary thermal processing and molding, which will effectively reduce scrap rates and reduce waste from the beginning. The plastic deformation of vitrimer can also endow item self-healing ability and extended its service life, and so contribute to environmental protection and emission reduction. In the paper stannous iso-octanoate as a catalyst and phenolic resin as a modifier was used to prepare anhydride cured epoxy vitrimer materials. The research results indicate that the increase in catalyst content could make the system cure more completely, so there is a certain improvement in the bending strength of the material, up to 87.5 MPa. With introduction of phenolic resin, the bending strength increases from 87.5 MPa before modification to 126.9 MPa, and the tensile strength reaches 63.3 MPa. When the amount of phenolic resin added is too high, the crosslinking density of the material decreases, and the mechanical properties of the material show a downward trend. The study on the relaxation behavior of the epoxy vitrimer system cured with pure anhydride shows that increasing the catalyst content reduces the relaxation time of the materials, but the post curing reaction at high temperature could inhibit the relaxation process and suppress the self-welding strength. The stress relaxation of epoxy vitrimer material modified with phenolic resin is significantly faster than that of epoxy vitrimer system cured with pure anhydride. The relaxation of the samples with 10mol% catalyst shows a sudden change, and there is a significant acceleration when the temperature rises to 190℃, and the introduction of phenolic resin could advance the sudden change temperature Ts to 180℃. Under no pressure conditions, scratches are repaired. The tensile shear strength and scratches repair effect of the samples repaired above Ts are significantly improved. Compared to samples without phenolic resin, phenolic modified samples could be repaired better. Catalyst have a significant impact on the repair strength and repair speed of the samples.
2024, 41(8): 4073-4083.
doi: 10.13801/j.cnki.fhclxb.20231219.002
Abstract:
The in-plane shear deformation behavior of unidirectional thermoset prepreg has significant effect on the forming quality and mechanical properties of composite parts after hot diaphragm forming. In this paper, the in-plane shear and stress relaxation behavior of unidirectional thermoset prepreg at different forming temperatures and loading rates were investigated. The test results show that the unidirectional thermoset prepreg exhibits a nonlinear in-plane shear deformation behavior strongly related to temperature and loading rate, and the sensitivity of shear deformation to loading rate decreases with the increasing of temperature. The relaxation rate of unidirectional thermoset prepreg accelerates with the increasing of temperature, and the sooner it is in a stable state. Based on the in-plane shear stress relaxation behavior of unidirectional thermoset prepreg, a generalized Maxwell viscoelastic constitutive model was constructed, which could accurately track fiber orientation change. The viscoelastic constitutive model was implemented in the user material subroutine VUMAT in Abaqus. The off-axis tensile stress relaxations were simulated. It is in good agreement with the experimental results, indicating the effectiveness of the viscoelastic constitutive model.
The in-plane shear deformation behavior of unidirectional thermoset prepreg has significant effect on the forming quality and mechanical properties of composite parts after hot diaphragm forming. In this paper, the in-plane shear and stress relaxation behavior of unidirectional thermoset prepreg at different forming temperatures and loading rates were investigated. The test results show that the unidirectional thermoset prepreg exhibits a nonlinear in-plane shear deformation behavior strongly related to temperature and loading rate, and the sensitivity of shear deformation to loading rate decreases with the increasing of temperature. The relaxation rate of unidirectional thermoset prepreg accelerates with the increasing of temperature, and the sooner it is in a stable state. Based on the in-plane shear stress relaxation behavior of unidirectional thermoset prepreg, a generalized Maxwell viscoelastic constitutive model was constructed, which could accurately track fiber orientation change. The viscoelastic constitutive model was implemented in the user material subroutine VUMAT in Abaqus. The off-axis tensile stress relaxations were simulated. It is in good agreement with the experimental results, indicating the effectiveness of the viscoelastic constitutive model.
2024, 41(8): 4084-4093.
doi: 10.13801/j.cnki.fhclxb.20240228.002
Abstract:
Using the method of combining quasi-static axial compression experiment with finite element simulation, the axial compression characteristics and failure mechanisms of 3D braided-unidirectional ply (3D-UD) hybrid tubes were investigated. Test results show that the peak load, total absorbed energy and specific energy absorption (SEA) of 3D-UD hybrid tube are increased by 20.3%, 109.2% and 67.1% respectively compared to the UD tube, and the compression energy absorption mode becomes more stable. In addition, the failure process of 3D-UD hybrid tubes was simulated by finite element method. The results show that load-displacement curves are in good accordance with experiment results so that the reliability of the simulation model is verified. Combined with the experimental results and the simulation analysis of the damage deformation of the mixed tube, it is found that the binding and supporting effects of the outer layer 3D and the inner layer 3D on the sandwich UD inhibit the breakage of the UD tube wall due to excessive bending. At the same time, the stability failure and energy absorption of the sandwich UD tube prevent the 3D tube from serious braided layer crimp. Therefore, the mixed tube can effectively resist the wall deformation and improve the stability and energy absorption under axial compression.
Using the method of combining quasi-static axial compression experiment with finite element simulation, the axial compression characteristics and failure mechanisms of 3D braided-unidirectional ply (3D-UD) hybrid tubes were investigated. Test results show that the peak load, total absorbed energy and specific energy absorption (SEA) of 3D-UD hybrid tube are increased by 20.3%, 109.2% and 67.1% respectively compared to the UD tube, and the compression energy absorption mode becomes more stable. In addition, the failure process of 3D-UD hybrid tubes was simulated by finite element method. The results show that load-displacement curves are in good accordance with experiment results so that the reliability of the simulation model is verified. Combined with the experimental results and the simulation analysis of the damage deformation of the mixed tube, it is found that the binding and supporting effects of the outer layer 3D and the inner layer 3D on the sandwich UD inhibit the breakage of the UD tube wall due to excessive bending. At the same time, the stability failure and energy absorption of the sandwich UD tube prevent the 3D tube from serious braided layer crimp. Therefore, the mixed tube can effectively resist the wall deformation and improve the stability and energy absorption under axial compression.
2024, 41(8): 4094-4102.
doi: 10.13801/j.cnki.fhclxb.20240229.004
Abstract:
With the extensive application of carbon fiber reinforced resin matrix composites in aerospace field, structure/function integrated composites will play a crucial part. In this paper, asphalt based carbon fiber (CF) reinforced cyanate ester composites with high thermal conductivity were prepared by functional interlayer technology (FIT). The film material graphene sheets (GNPs)-Al2O3/CF prepared by electrophoretic deposition of GNPs and Al2O3 on the surface of the short-cut carbon fiber film was used as the functional interlayer film to replace the resin-rich layer region between the fiber layers. The in-plane thermal conductivity and through-plane thermal conductivity of orthogonal lamination composites are increased by 123.1% and 77.5%. The in-plane thermal conductivity and through-plane thermal conductivity of quasi-anisotropic lamination composites are increased by 119.0% and 50.0%, respectively. In addition, the addition of multifunctional intercalation structure can prevent the propagation of cracks and improve the interlaminar toughness of composites. Therefore, the multifunctional intercalation structure can not only form an effective thermal network structure between the layers to improve the in-plane and out-of-plane thermal conductivity of the composite, but also improve the toughening efficiency of the interlayer region.
With the extensive application of carbon fiber reinforced resin matrix composites in aerospace field, structure/function integrated composites will play a crucial part. In this paper, asphalt based carbon fiber (CF) reinforced cyanate ester composites with high thermal conductivity were prepared by functional interlayer technology (FIT). The film material graphene sheets (GNPs)-Al2O3/CF prepared by electrophoretic deposition of GNPs and Al2O3 on the surface of the short-cut carbon fiber film was used as the functional interlayer film to replace the resin-rich layer region between the fiber layers. The in-plane thermal conductivity and through-plane thermal conductivity of orthogonal lamination composites are increased by 123.1% and 77.5%. The in-plane thermal conductivity and through-plane thermal conductivity of quasi-anisotropic lamination composites are increased by 119.0% and 50.0%, respectively. In addition, the addition of multifunctional intercalation structure can prevent the propagation of cracks and improve the interlaminar toughness of composites. Therefore, the multifunctional intercalation structure can not only form an effective thermal network structure between the layers to improve the in-plane and out-of-plane thermal conductivity of the composite, but also improve the toughening efficiency of the interlayer region.
2024, 41(8): 4103-4112.
doi: 10.13801/j.cnki.fhclxb.20240003.004
Abstract:
Epoxy resins play a crucial role in providing insulation, support, and protection for the electrification process in transportation. However, the conventional methods of recycling epoxy resins are quite complex and do not align with the sustainability goals of green transportation. There is an urgent need to develop environmentally friendly and recyclable epoxy resins. To address the issues related to the physical, chemical, and electrical properties of recyclable epoxy resins, this paper introduces a novel photothermal dual-curing method that combines photosensitive oil-based resin with epoxy resin. This innovative approach leverages the transesterification mechanism to recover the dual-curing epoxy resin under high-temperature and high-pressure conditions without the need for a catalyst. Remarkably, the recovered resin retains excellent physical, chemical, and electrical properties. The study demonstrates that the initial properties of the dual-curing epoxy resin are promising. The quality of the recovered resin improves with smaller resin particle sizes and higher hot pressing pressures. After undergoing a hot pressing process at 220℃ and 10 MPa for 3 h, the recovered resin exhibits its best comprehensive properties, with recovery rates of 92.0% for bending strength and 93.7% for tensile strength. Furthermore, the dielectric constant and dielectric loss at power frequency remain largely unchanged compared to their values before recovery, with a remarkable breakdown strength recovery rate of 98.4%. This research highlights the significant potential and application prospects of dual-curing epoxy resin in advancing the electrification of transportation.
Epoxy resins play a crucial role in providing insulation, support, and protection for the electrification process in transportation. However, the conventional methods of recycling epoxy resins are quite complex and do not align with the sustainability goals of green transportation. There is an urgent need to develop environmentally friendly and recyclable epoxy resins. To address the issues related to the physical, chemical, and electrical properties of recyclable epoxy resins, this paper introduces a novel photothermal dual-curing method that combines photosensitive oil-based resin with epoxy resin. This innovative approach leverages the transesterification mechanism to recover the dual-curing epoxy resin under high-temperature and high-pressure conditions without the need for a catalyst. Remarkably, the recovered resin retains excellent physical, chemical, and electrical properties. The study demonstrates that the initial properties of the dual-curing epoxy resin are promising. The quality of the recovered resin improves with smaller resin particle sizes and higher hot pressing pressures. After undergoing a hot pressing process at 220℃ and 10 MPa for 3 h, the recovered resin exhibits its best comprehensive properties, with recovery rates of 92.0% for bending strength and 93.7% for tensile strength. Furthermore, the dielectric constant and dielectric loss at power frequency remain largely unchanged compared to their values before recovery, with a remarkable breakdown strength recovery rate of 98.4%. This research highlights the significant potential and application prospects of dual-curing epoxy resin in advancing the electrification of transportation.
2024, 41(8): 4113-4123.
doi: 10.13801/j.cnki.fhclxb.20240008.007
Abstract:
Aircraft, satellites and other aircraft with key electronic components, are susceptible to interference from strong electromagnetic field. And some structures of aircraft need to meet mechanical requirements such as large deformation and stretchability in work. Therefore, highly conductive and stretchable electromagnetic shielding materials have attracted widespread attention. Using graphene oxide as raw material and through casting method and high-temperature graphitization treatment, a highly conductive and flexible graphene film compressed with four layer porous fims (GP-4) with the thickness of 13.5 μm was prepared, whose electrical conductivity and electromagnetic shielding efficiency were6010 S/cm and 68.4 dB, respectively. Using polydimethylsilane (PDMS) as the base, GP-4/PDMS-50.5 composite film with stretchable bilayer structure was prepared, whose elongation was as high as 50.5%. When the axial tensile strain of the composite film is 50.5% and the number of stretching cycles is 500, the composite film could still maintain excellent conductivity and electromagnetic shielding performance. Among them, the resistance of the composite film is 1.04 Ω and 1.06 Ω, keeping constant with the GP-4 film almost. The electromagnetic shielding efficiency of the composite film is as high as 68.5 dB and 67.7 dB. These excellent properties indicate that GP-4/PDMS-50.5 composite film has great application prospects in the electromagnetic shielding field of flexible electronic devices.
Aircraft, satellites and other aircraft with key electronic components, are susceptible to interference from strong electromagnetic field. And some structures of aircraft need to meet mechanical requirements such as large deformation and stretchability in work. Therefore, highly conductive and stretchable electromagnetic shielding materials have attracted widespread attention. Using graphene oxide as raw material and through casting method and high-temperature graphitization treatment, a highly conductive and flexible graphene film compressed with four layer porous fims (GP-4) with the thickness of 13.5 μm was prepared, whose electrical conductivity and electromagnetic shielding efficiency were
2024, 41(8): 4124-4133.
doi: 10.13801/j.cnki.fhclxb.20231220.003
Abstract:
With the rapid development of high-frequency communication technology, electromagnetic interference (EMI) issue has been increasing. Hence, EMI shielding materials for the 5G frequency band are in high demand. Here, a two-step laser-induced strategy was developed to rapidly prepare silver nanoparticles/porous graphene flexible composite in a solid-phase synthesis process. AgNO3 solution can be efficiently adsorbed by hydrophilic laser-induced graphene (LIG) obtained by the first laser irradiation with tuned parameters, which provides favorable conditions for the abundant and homogeneous loading of Ag nanoparticles on LIG after in-situ the second laser irradiation. Furthermore, the microstructures, structural properties and electronic conductivity of the prepared Ag/LIG composites with different AgNO3 additive concentrations are detailedly analyzed. As a result, with a 0.5 mol/L AgNO3 additive concentration, Ag nanoparticles in the composite film maintain small size while exhibiting the best dispersion, exhibiting a high conductivity of2788 S/m. In the 18-27 GHz frequency band, the EMI shielding effectiveness increases from 18-26 dB of LIG to 36-40 dB of composite materials. The EMI shielding effectiveness of Ag/LIG-0.5 at the 26 GHz reaches 38 dB with an over 90% shielding effectiveness retention rate after 200 bending cycles.
With the rapid development of high-frequency communication technology, electromagnetic interference (EMI) issue has been increasing. Hence, EMI shielding materials for the 5G frequency band are in high demand. Here, a two-step laser-induced strategy was developed to rapidly prepare silver nanoparticles/porous graphene flexible composite in a solid-phase synthesis process. AgNO3 solution can be efficiently adsorbed by hydrophilic laser-induced graphene (LIG) obtained by the first laser irradiation with tuned parameters, which provides favorable conditions for the abundant and homogeneous loading of Ag nanoparticles on LIG after in-situ the second laser irradiation. Furthermore, the microstructures, structural properties and electronic conductivity of the prepared Ag/LIG composites with different AgNO3 additive concentrations are detailedly analyzed. As a result, with a 0.5 mol/L AgNO3 additive concentration, Ag nanoparticles in the composite film maintain small size while exhibiting the best dispersion, exhibiting a high conductivity of
2024, 41(8): 4134-4145.
doi: 10.13801/j.cnki.fhclxb.20240003.003
Abstract:
Smart food packaging can make up for the shortcomings of traditional packaging in real-time quality monitoring, so exploiting a low cost, harmless to human health and green food freshness intelligent indicator label is of great significance for food safety. Therefore, in this study, we employed regenerated cellulose (RC) films, anthocyanidin extracted from red cabbage and nano-SiO2 to fabricate a biodegradable smart colorimetric sensing film (SiO2-PCE/RCG). This film has good mechanical properties (Maximum stress is 67.1 MPa, and maximum tensile strain is 45.50%) and super-hydrophobicity (Water contact angle is 152.8°), and has a certain barrier ability to ultraviolet light, which can be used for real-time monitoring of fresh food freshness. In addition, the effectiveness of the film in detecting the freshness of shrimp was confirmed by measuring the total volatile basic nitrogen (TVBN) and pH value, and its color obviously changes from magenta to water-red, then to grey-purple, and then to grey-green, effectively indicating the spoilage of shrimp. The colorimetric sensing film developed here would be used as an intelligent colorimetric label with good mechanical properties and super-hydrophobicity, and can be applied to intelligent packaging that can monitor the freshness of food in real time.
Smart food packaging can make up for the shortcomings of traditional packaging in real-time quality monitoring, so exploiting a low cost, harmless to human health and green food freshness intelligent indicator label is of great significance for food safety. Therefore, in this study, we employed regenerated cellulose (RC) films, anthocyanidin extracted from red cabbage and nano-SiO2 to fabricate a biodegradable smart colorimetric sensing film (SiO2-PCE/RCG). This film has good mechanical properties (Maximum stress is 67.1 MPa, and maximum tensile strain is 45.50%) and super-hydrophobicity (Water contact angle is 152.8°), and has a certain barrier ability to ultraviolet light, which can be used for real-time monitoring of fresh food freshness. In addition, the effectiveness of the film in detecting the freshness of shrimp was confirmed by measuring the total volatile basic nitrogen (TVBN) and pH value, and its color obviously changes from magenta to water-red, then to grey-purple, and then to grey-green, effectively indicating the spoilage of shrimp. The colorimetric sensing film developed here would be used as an intelligent colorimetric label with good mechanical properties and super-hydrophobicity, and can be applied to intelligent packaging that can monitor the freshness of food in real time.
2024, 41(8): 4146-4159.
doi: 10.13801/j.cnki.fhclxb.20231214.002
Abstract:
Conductive polymer composites (CPCs) are widely used for the preparation of electromagnetic shielding materials due to their good comprehensive performance such as good corrosion resistance, high specific strength, low cost and easy processing. In this paper, MXene-carboxylated carbon nanotube/polyimide (MXene-CCNT/PI) composite films with good comprehensive performance were prepared by a simple scraping and thermal imidization method. The synergistic action of MXene and CCNT constructed a good conductive network, which gave the films high efficient electromagnetic shielding performance (EMI SE). When the contents of both MXene and CCNT were 12.5wt%, the film thickness was 80 μm, the conductivity was 5.88 S/cm, the EMI SE was 26.49 dB, and the ratio of electromagnetic shielding effectiveness to thickness (EMI SE/t) was 331.13 dB/mm. Moreover, the film showed long-lasting and stable EMI SE under extreme environments (acid-alkali treatment, high and low temperature treatment, and repetitive bending). At the same time, the MXene-CCNT/PI film still have a tensile strength of 53.17 MPa, excellent thermal stability (>500℃), and flame retardancy. Convenient and efficient preparation of polymer-based EMI shielding composites is realized, taking into account their excellent mechanical properties and heat resistance.
Conductive polymer composites (CPCs) are widely used for the preparation of electromagnetic shielding materials due to their good comprehensive performance such as good corrosion resistance, high specific strength, low cost and easy processing. In this paper, MXene-carboxylated carbon nanotube/polyimide (MXene-CCNT/PI) composite films with good comprehensive performance were prepared by a simple scraping and thermal imidization method. The synergistic action of MXene and CCNT constructed a good conductive network, which gave the films high efficient electromagnetic shielding performance (EMI SE). When the contents of both MXene and CCNT were 12.5wt%, the film thickness was 80 μm, the conductivity was 5.88 S/cm, the EMI SE was 26.49 dB, and the ratio of electromagnetic shielding effectiveness to thickness (EMI SE/t) was 331.13 dB/mm. Moreover, the film showed long-lasting and stable EMI SE under extreme environments (acid-alkali treatment, high and low temperature treatment, and repetitive bending). At the same time, the MXene-CCNT/PI film still have a tensile strength of 53.17 MPa, excellent thermal stability (>500℃), and flame retardancy. Convenient and efficient preparation of polymer-based EMI shielding composites is realized, taking into account their excellent mechanical properties and heat resistance.
2024, 41(8): 4160-4170.
doi: 10.13801/j.cnki.fhclxb.20231215.003
Abstract:
Harmful algal blooms (HABs) outbreaks due to eutrophication of water bodies are becoming increasingly serious, posing a great threat to the water environment and human health. In this paper, magnetic and recoverable nickel-doped ZnFe2O4 (Ni-ZFO) adsorbents were prepared by a simple hydrothermal method for the removal of microcystis aeruginosa from water bodies. The materials were characterized by SEM, XRD, EDS, XPS and vibrating sample magnetometer (VSM). The algal cell removal of Ni-ZFO composites was up to 99.09% within 30 min and remained above 90.41% at 25℃ and pH=3-8. In addition, the saturation magnetization intensity of Ni-ZFO was 67.93 emu/g, which was 10.74 emu/g higher than that of ZnFe2O4 (ZFO), and it was easy to be recycled. The content of algal bile proteins did not increase in the adsorption process, and the algal cells would not be ruptured during the adsorption process, which avoids the secondary pollution caused by Microcystins entering the water environment. The algal removal rate remained above 75% after four times of recycling. The Ni-ZFO adsorbent synthesized in this paper has strong removal efficiency for algal cells and does not cause secondary pollution, which shows great potential in the practical application of mitigating eutrophication of water bodies, and also enriches the application of modified ZFO in the field of adsorption.
Harmful algal blooms (HABs) outbreaks due to eutrophication of water bodies are becoming increasingly serious, posing a great threat to the water environment and human health. In this paper, magnetic and recoverable nickel-doped ZnFe2O4 (Ni-ZFO) adsorbents were prepared by a simple hydrothermal method for the removal of microcystis aeruginosa from water bodies. The materials were characterized by SEM, XRD, EDS, XPS and vibrating sample magnetometer (VSM). The algal cell removal of Ni-ZFO composites was up to 99.09% within 30 min and remained above 90.41% at 25℃ and pH=3-8. In addition, the saturation magnetization intensity of Ni-ZFO was 67.93 emu/g, which was 10.74 emu/g higher than that of ZnFe2O4 (ZFO), and it was easy to be recycled. The content of algal bile proteins did not increase in the adsorption process, and the algal cells would not be ruptured during the adsorption process, which avoids the secondary pollution caused by Microcystins entering the water environment. The algal removal rate remained above 75% after four times of recycling. The Ni-ZFO adsorbent synthesized in this paper has strong removal efficiency for algal cells and does not cause secondary pollution, which shows great potential in the practical application of mitigating eutrophication of water bodies, and also enriches the application of modified ZFO in the field of adsorption.
2024, 41(8): 4171-4179.
doi: 10.13801/j.cnki.fhclxb.20231214.003
Abstract:
Micro-encapsulated phase change materials (MPCM) was used as energy storage elements and combined with desulfurized gypsum. Effects of MPCM on the mechanical properties, thermal properties and thermal cycle stability of desulfurized gypsum-based composites were investigated. Results show that the latent heat energy storage capacity of MPCM can not only adjust the hydration temperature rise of the slurry, but also gave the composite the power to store energy and regulate temperature. However, the addition of MPCM has a negative effect on the strength of the composite. When the MPCM content is 50wt%, the comprehensive properties of the composite are better. At this time, the phase transition temperature and enthalpy of the composite are 24.51℃ and 28.47 J·g−1, respectively. The temperature peak during heat storage stage and the time to reach the peak temperature are reduced and delayed by 6.4℃ and 980 s, when compared with pure gypsum. The effect of heat storage and temperature control is obvious. The thermal conductivity of the composite is 0.451 W·(m·K)−1 and its 28 days compressive strength is 25.05 MPa. The mass loss rate, phase change temperature change rate and phase change enthalpy change rate of 250 cold hot cycles are 0.67%, 0.08% and 2.3%, respectively, and the thermal cycle stability is good. Phase change energy storage gypsum has good mechanical properties, thermal properties and thermal cycle stability, and has broad application prospects in building envelope structure.
Micro-encapsulated phase change materials (MPCM) was used as energy storage elements and combined with desulfurized gypsum. Effects of MPCM on the mechanical properties, thermal properties and thermal cycle stability of desulfurized gypsum-based composites were investigated. Results show that the latent heat energy storage capacity of MPCM can not only adjust the hydration temperature rise of the slurry, but also gave the composite the power to store energy and regulate temperature. However, the addition of MPCM has a negative effect on the strength of the composite. When the MPCM content is 50wt%, the comprehensive properties of the composite are better. At this time, the phase transition temperature and enthalpy of the composite are 24.51℃ and 28.47 J·g−1, respectively. The temperature peak during heat storage stage and the time to reach the peak temperature are reduced and delayed by 6.4℃ and 980 s, when compared with pure gypsum. The effect of heat storage and temperature control is obvious. The thermal conductivity of the composite is 0.451 W·(m·K)−1 and its 28 days compressive strength is 25.05 MPa. The mass loss rate, phase change temperature change rate and phase change enthalpy change rate of 250 cold hot cycles are 0.67%, 0.08% and 2.3%, respectively, and the thermal cycle stability is good. Phase change energy storage gypsum has good mechanical properties, thermal properties and thermal cycle stability, and has broad application prospects in building envelope structure.
2024, 41(8): 4180-4188.
doi: 10.13801/j.cnki.fhclxb.20240010.001
Abstract:
Carbon/carbon composites has been widely used in aerospace, weaponry and other fields with their excellent properties. However, the development of carbon/carbon composites has been limited by the high cost of carbon fiber preforms. Carbon foam has a three-dimensional network structure, and its ligaments show similar properties to carbon fibers, which can be used as the reinforcing phase to prepare carbon/carbon composites. In this paper, carbon foams with different carbon fiber volume contents (0vol%, 1vol%, 3vol%, 5vol%, 7vol%) were prepared as carbon/carbon composites preforms by using phenolic resin as the carbon source and NaCl as the pore-forming agent, and the carbon/carbon composites were prepared by using the rapid densification technique of thermal gradient chemical vapour infiltration (TG-CVI), which investigated the effects of carbon fiber content on the carbon fiber/carbon foam preform and its density, microstructure and mechanical properties after densification. The effects of carbon fiber content on the density, microstructure and mechanical properties of the carbon fiber/carbon foam preform and its densification were investigated. The results showed that with the increase of carbon fiber content, the number of microcracks in the carbon fiber/carbon foam precast body increased significantly, the density gradually decreased from 0.51 g/cm3 to 0.31 g/cm3, and the compressive strength decreased from 51.33 MPa to 1.35 MPa, flexural strength decreased from 42.53 MPa to 6.32 MPa. The compressive and flexural strengths of the carbon/carbon composites were significantly increased after densification, up to 183.67 MPa and 123.46 MPa, respectively, while the density was 1.09 g/cm3, resulting in high specific strength. The thermal conductivity of the composites increased from 0.298 W/(m·K) (before densification) to 2.484 W/(m·K), an increase of 734%, which was attributed to the formation of a three-dimensional thermal conductivity network between the carbon fibers and pyrolytic carbon after densification.
Carbon/carbon composites has been widely used in aerospace, weaponry and other fields with their excellent properties. However, the development of carbon/carbon composites has been limited by the high cost of carbon fiber preforms. Carbon foam has a three-dimensional network structure, and its ligaments show similar properties to carbon fibers, which can be used as the reinforcing phase to prepare carbon/carbon composites. In this paper, carbon foams with different carbon fiber volume contents (0vol%, 1vol%, 3vol%, 5vol%, 7vol%) were prepared as carbon/carbon composites preforms by using phenolic resin as the carbon source and NaCl as the pore-forming agent, and the carbon/carbon composites were prepared by using the rapid densification technique of thermal gradient chemical vapour infiltration (TG-CVI), which investigated the effects of carbon fiber content on the carbon fiber/carbon foam preform and its density, microstructure and mechanical properties after densification. The effects of carbon fiber content on the density, microstructure and mechanical properties of the carbon fiber/carbon foam preform and its densification were investigated. The results showed that with the increase of carbon fiber content, the number of microcracks in the carbon fiber/carbon foam precast body increased significantly, the density gradually decreased from 0.51 g/cm3 to 0.31 g/cm3, and the compressive strength decreased from 51.33 MPa to 1.35 MPa, flexural strength decreased from 42.53 MPa to 6.32 MPa. The compressive and flexural strengths of the carbon/carbon composites were significantly increased after densification, up to 183.67 MPa and 123.46 MPa, respectively, while the density was 1.09 g/cm3, resulting in high specific strength. The thermal conductivity of the composites increased from 0.298 W/(m·K) (before densification) to 2.484 W/(m·K), an increase of 734%, which was attributed to the formation of a three-dimensional thermal conductivity network between the carbon fibers and pyrolytic carbon after densification.
2024, 41(8): 4189-4199.
doi: 10.13801/j.cnki.fhclxb.20231214.004
Abstract:
In order to improve the durability of photochromic coated fabrics, the photochromic microcapsules (PM) and zwitterionic polyurethane (ZPU) were used to prepare PM/ZPU films, which were then hot-pressed onto cotton fabrics to obtain the self-healing PM/ZPU composite fabrics. The structure and morphology of PM/ZPU composite fabric were characterized, and the photochromic properties, self-healing and recycling ability of PM/ZPU composite fabric were discussed in detail. The results show that the maximum absorption wavelength of PM/ZPU composite fabric changes from 470 nm to 530 nm, the color changes from yellow-orange to reddish-brown, and the fabric has good fatigue resistance. Based on the dynamic reversibility of zwitterionic, the scratches of PM/ZPU composite fabric can be completely repaired at 80℃, and the bond strength of the fractured composite fabric reaches 1.47 MPa at 60℃, showing excellent self-healing properties. The coating on the waste fabric can be recycled and reused by a simple dissolution method, and the PM/ZPU composite fabric can still be prepared with good photochromic properties.
In order to improve the durability of photochromic coated fabrics, the photochromic microcapsules (PM) and zwitterionic polyurethane (ZPU) were used to prepare PM/ZPU films, which were then hot-pressed onto cotton fabrics to obtain the self-healing PM/ZPU composite fabrics. The structure and morphology of PM/ZPU composite fabric were characterized, and the photochromic properties, self-healing and recycling ability of PM/ZPU composite fabric were discussed in detail. The results show that the maximum absorption wavelength of PM/ZPU composite fabric changes from 470 nm to 530 nm, the color changes from yellow-orange to reddish-brown, and the fabric has good fatigue resistance. Based on the dynamic reversibility of zwitterionic, the scratches of PM/ZPU composite fabric can be completely repaired at 80℃, and the bond strength of the fractured composite fabric reaches 1.47 MPa at 60℃, showing excellent self-healing properties. The coating on the waste fabric can be recycled and reused by a simple dissolution method, and the PM/ZPU composite fabric can still be prepared with good photochromic properties.
2024, 41(8): 4200-4210.
doi: 10.13801/j.cnki.fhclxb.20231205.004
Abstract:
With the development of communication networks, wireless devices and aerospace industries. Electromagnetic wave hazards become prevalent. Therefore, it is essential to develop composites with better electromagnetic shielding properties. In this paper, highly conductive three-dimensional (conductivity up to 1.4×104 S·m−1) networked electromagnetic shielding composite films (Ti3C2Tx MXene-based functional composite films) were constructed using MXene (Ti3C2Tx), silver nanowires (AgNWs) and multi-walled carbon nanotubes (MWCNTs) in a bilayer. In particular, the aqueous solutions of 10 mL AgNWs and 15 mL Ti3C2Tx MXene were adsorbed on top of poly(vinylidene fluoride) (PVDF)/MWCNTs composite films by vacuum-assisted filtration (VAF), and the total electromagnetic interference shielding effectiveness (EMI SET) of the Ti3C2Tx MXene-based functional composite film was as high as 69.0 dB, which was 245% higher than that of the commercial standard (20 dB), of which the absorption loss effectiveness (SEA) accounted for 85.1%. It is shown that the main electromagnetic loss mechanism of Ti3C2Tx MXene-based functional composite films is absorption loss, with a specific electromagnetic shielding effectiveness (SSE/t) of up to2719.8 dB/(cm−2·g). This work provides structural design and research ideas for the application of novel MXene materials in electromagnetic shielding composites.
With the development of communication networks, wireless devices and aerospace industries. Electromagnetic wave hazards become prevalent. Therefore, it is essential to develop composites with better electromagnetic shielding properties. In this paper, highly conductive three-dimensional (conductivity up to 1.4×104 S·m−1) networked electromagnetic shielding composite films (Ti3C2Tx MXene-based functional composite films) were constructed using MXene (Ti3C2Tx), silver nanowires (AgNWs) and multi-walled carbon nanotubes (MWCNTs) in a bilayer. In particular, the aqueous solutions of 10 mL AgNWs and 15 mL Ti3C2Tx MXene were adsorbed on top of poly(vinylidene fluoride) (PVDF)/MWCNTs composite films by vacuum-assisted filtration (VAF), and the total electromagnetic interference shielding effectiveness (EMI SET) of the Ti3C2Tx MXene-based functional composite film was as high as 69.0 dB, which was 245% higher than that of the commercial standard (20 dB), of which the absorption loss effectiveness (SEA) accounted for 85.1%. It is shown that the main electromagnetic loss mechanism of Ti3C2Tx MXene-based functional composite films is absorption loss, with a specific electromagnetic shielding effectiveness (SSE/t) of up to
2024, 41(8): 4211-4224.
doi: 10.13801/j.cnki.fhclxb.20231129.001
Abstract:
In order to study the effects of different resin (epoxy resin, furan resin, vinyl resin) coatings and seawater immersion on the mechanical properties of basalt textile reinforced seawater sea sand concrete (BTR-SSC), a universal testing machine was used to perform static tensile tests on the fiber yarns of each resin coating and the BTR-SSC specimens immersed in seawater for different time, and the fiber-matrix interface bonding performance was evaluated by pull-out test. The crack and strain distribution were obtained by digital image correlation analysis, and the damage mechanism was analyzed by scanning electron microscopy. The long-term performance of the interface was evaluated by crack distribution and matrix strength through the calculation formula of interface bond strength. The results show that the reinforcing effects of the three resins on the fiber yarns are significant and similar (around 32%), which could significantly improve the mechanical properties of BTR-SSC. The vinyl resin coating had the best performance, and the tensile properties and interfacial bonding properties are increased by 77% and 180%, respectively. The mechanical properties of BTR-SSC specimens are significantly degraded under seawater immersion. The untreated specimens are brittle after 14 days of high temperature immersion. The tensile strength of epoxy resin, furan resin and vinyl resin coated specimens increase by 81%, 48% and 94% respectively after 7 days of immersion compared with untreated specimens. After 28 days of immersion, there are still multiple cracks developed, and the interfacial bonding properties are lost by 64%, 57% and 55%, respectively. The results will help to improve the long-term performance of BTR-SSC in the marine environment and promote its application in marine structures.
In order to study the effects of different resin (epoxy resin, furan resin, vinyl resin) coatings and seawater immersion on the mechanical properties of basalt textile reinforced seawater sea sand concrete (BTR-SSC), a universal testing machine was used to perform static tensile tests on the fiber yarns of each resin coating and the BTR-SSC specimens immersed in seawater for different time, and the fiber-matrix interface bonding performance was evaluated by pull-out test. The crack and strain distribution were obtained by digital image correlation analysis, and the damage mechanism was analyzed by scanning electron microscopy. The long-term performance of the interface was evaluated by crack distribution and matrix strength through the calculation formula of interface bond strength. The results show that the reinforcing effects of the three resins on the fiber yarns are significant and similar (around 32%), which could significantly improve the mechanical properties of BTR-SSC. The vinyl resin coating had the best performance, and the tensile properties and interfacial bonding properties are increased by 77% and 180%, respectively. The mechanical properties of BTR-SSC specimens are significantly degraded under seawater immersion. The untreated specimens are brittle after 14 days of high temperature immersion. The tensile strength of epoxy resin, furan resin and vinyl resin coated specimens increase by 81%, 48% and 94% respectively after 7 days of immersion compared with untreated specimens. After 28 days of immersion, there are still multiple cracks developed, and the interfacial bonding properties are lost by 64%, 57% and 55%, respectively. The results will help to improve the long-term performance of BTR-SSC in the marine environment and promote its application in marine structures.
2024, 41(8): 4225-4235.
doi: 10.13801/j.cnki.fhclxb.20240013.001
Abstract:
Alkali-silica reaction (ASR) is a reaction between alkaline pore solutions in concrete and reactive non-crystalline SiO2 in aggregates, which leads to expansion and cracking of the concrete, and degradation of mechanical properties. In this study, based on the microbial induced calcium carbonate precipitation (MICP) technique of Bacillus pasteurus, various treatment frequencies and methods, including surface treatments of potentially active aggregates and mortar bars made by them, to comprehensively evaluate the inhibition law and mechanism of MICP on ASR. The results showed that the MICP treatment could form a dense CaCO3 layer with adhesive effect on the surface of aggregates and mortar bars, thus preventing the intrusion of alkaline ions and water, and the inhibiting effect became stronger with the treatment numbers. Compared with the control group, the maximum increase in mechanical properties of 13.8%, and the decrease in expansion rate of 35% were observed when the mortar bars were treated. When treating the aggregate, the mechanical properties were improved by 25.3% and the expansion rate was reduced by 59.6% with a better inhibition effect, as the surface CaCO3 layer could simultaneously block the alkaline ions and water existing in the pore solution and invading from outside. Microstructural and compositional analyses showed that the proportion of Si and Na atoms on the aggregate surface decreased by 69.6% and 88.9%, respectively, after treatment, indicating a significant reduction in the ASR gel.
Alkali-silica reaction (ASR) is a reaction between alkaline pore solutions in concrete and reactive non-crystalline SiO2 in aggregates, which leads to expansion and cracking of the concrete, and degradation of mechanical properties. In this study, based on the microbial induced calcium carbonate precipitation (MICP) technique of Bacillus pasteurus, various treatment frequencies and methods, including surface treatments of potentially active aggregates and mortar bars made by them, to comprehensively evaluate the inhibition law and mechanism of MICP on ASR. The results showed that the MICP treatment could form a dense CaCO3 layer with adhesive effect on the surface of aggregates and mortar bars, thus preventing the intrusion of alkaline ions and water, and the inhibiting effect became stronger with the treatment numbers. Compared with the control group, the maximum increase in mechanical properties of 13.8%, and the decrease in expansion rate of 35% were observed when the mortar bars were treated. When treating the aggregate, the mechanical properties were improved by 25.3% and the expansion rate was reduced by 59.6% with a better inhibition effect, as the surface CaCO3 layer could simultaneously block the alkaline ions and water existing in the pore solution and invading from outside. Microstructural and compositional analyses showed that the proportion of Si and Na atoms on the aggregate surface decreased by 69.6% and 88.9%, respectively, after treatment, indicating a significant reduction in the ASR gel.
2024, 41(8): 4236-4245.
doi: 10.13801/j.cnki.fhclxb.20231109.001
Abstract:
In order to study the microstructure characteristics of basalt fiber reinforced foam concrete and the influence of different fiber content on its damage characteristics, this paper carried out X-CT test and uniaxial compression acoustic emission joint test on basalt fiber reinforced foam concrete with density grade of1000 kg/cm3. Based on Avizo image processing and acoustic emission basic parameters and bi values (Improved b value), the microstructure characteristics of fibers and pores and the damage evolution characteristics of materials were analyzed. The results show that the addition of basalt fiber can effectively improve the mechanical properties of foam concrete. The average compressive strength of the specimens with 0.5vol%, 1.5vol% and 2.5vol% fibers increase by 1.37 MPa, 4.58 MPa and 2.77 MPa, respectively. The fiber fractal dimension of the specimen with 2.5vol% content is mainly in the range of 1.0-1.3, the fiber agglomeration is obvious, the fiber angle is concentrated, and the performance of the specimen is reduced. After adding basalt fiber, the trend of acoustic emission bi value of the specimen is gentler, and basalt fiber can effectively inhibit crack development.
In order to study the microstructure characteristics of basalt fiber reinforced foam concrete and the influence of different fiber content on its damage characteristics, this paper carried out X-CT test and uniaxial compression acoustic emission joint test on basalt fiber reinforced foam concrete with density grade of
2024, 41(8): 4246-4258.
doi: 10.13801/j.cnki.fhclxb.20240008.005
Abstract:
54 fiber-wound glass fiber reinforced polymer (GFRP) tube confined concrete cylindrical specimens classified in eighteen groups were designed and manufactured, and the parameters included the number of fiber layers (6, 10), fiber angle (\begin{document}$ \pm 45^\circ $\end{document} \begin{document}$ \pm 60^\circ $\end{document} \begin{document}$ \pm 80^\circ $\end{document}
54 fiber-wound glass fiber reinforced polymer (GFRP) tube confined concrete cylindrical specimens classified in eighteen groups were designed and manufactured, and the parameters included the number of fiber layers (6, 10), fiber angle (
2024, 41(8): 4259-4271.
doi: 10.13801/j.cnki.fhclxb.20231215.002
Abstract:
The stress-strain characteristics and damage evolution of polypropylene fiber coral seawater concrete (PPF/CAC) under uniaxial cyclic compression were studied. A total of 20 samples with different fiber volume fractions were tested. The failure form of PPF/CAC was observed in the test, and the stress-strain curve, peak stress-strain, plastic strain and other important indexes were obtained. The results show that the strength of specimens under cyclic loading is reduces by 1.21%-3.67% compared with that under monochrome loading, and the degradation can be slowed down with the increase of fiber content. The peak stress and peak strain increases are the largest when the polypropylene fiber volume fraction is 0.15vol%, which are 10.45% and 6.45%, respectively. In addition, the increase of PPF volume fraction can significantly reduce the accumulation of plastic strain and increase the elastic stiffness ratio. According to the test results, four characteristic points of hysteresis curve are defined: Unloading point, common point, residual point and end point. And the relationship between residual strain, common point strain and end point strain and unloading strain is established. Finally, the stress-strain constitutive equation and damage constitutive model of PPF/CAC under cyclic load are proposed, and the simplified stress-strain constitutive equation based on the damage evolution law can effectively predict the stress-strain behavior of PPF/CAC under cyclic load.
The stress-strain characteristics and damage evolution of polypropylene fiber coral seawater concrete (PPF/CAC) under uniaxial cyclic compression were studied. A total of 20 samples with different fiber volume fractions were tested. The failure form of PPF/CAC was observed in the test, and the stress-strain curve, peak stress-strain, plastic strain and other important indexes were obtained. The results show that the strength of specimens under cyclic loading is reduces by 1.21%-3.67% compared with that under monochrome loading, and the degradation can be slowed down with the increase of fiber content. The peak stress and peak strain increases are the largest when the polypropylene fiber volume fraction is 0.15vol%, which are 10.45% and 6.45%, respectively. In addition, the increase of PPF volume fraction can significantly reduce the accumulation of plastic strain and increase the elastic stiffness ratio. According to the test results, four characteristic points of hysteresis curve are defined: Unloading point, common point, residual point and end point. And the relationship between residual strain, common point strain and end point strain and unloading strain is established. Finally, the stress-strain constitutive equation and damage constitutive model of PPF/CAC under cyclic load are proposed, and the simplified stress-strain constitutive equation based on the damage evolution law can effectively predict the stress-strain behavior of PPF/CAC under cyclic load.
2024, 41(8): 4272-4286.
doi: 10.13801/j.cnki.fhclxb.20231129.003
Abstract:
Polymer has broad application prospects in soil stabilization. However, there is currently little research on the strength and deformation characteristics of polymer treated soil, as well as the degree of influence of different influencing factors. In this work, a series of unconfined compression strength and shear strength tests were performed on a water-soluble polymer treated sand, and subsequently, the effects of polymer content, curing time and dry density on the strength and deformation characteristics of the treated sand were analyzed. Also, the degree of influence of the three research variables was elucidated using correlation analysis. And finally, the related mechanism of treated sand was revealed using SEM observations. The results show that: (1) The three studied variables significantly enhance the unconfined compression strength and shear strength, and the influence of polymer content and curing time on shear strength was mainly reflected in the cohesion. The strength of polymer treated sand is significantly and positively correlated with curing time, and moderately and positively correlated with polymer content and dry density. In addition, these relationships can be represented by a logarithmic function or linear function. (2) As the polymer content, curing time and dry density increase, the shear characteristics of treated sand change from shear hardening type to shear softening type, and the shear failure displacement of treated sand decreases gradually (as dry densities decreases). Also, its axial stress-strain curve shows obvious post-peak easing phenomenon and then produces obvious changes, and the compression failure pattern is dominated by bulging and accompanied by cracks, what's more, this pattern gradually changes from E-type to G-type (as dry densities decreases). (3) The deformation capacity of treated sand is strongly and positively correlated with curing time, moderately and positively correlated with dry density, while the correlation with polymer content is not significant. Additionally, the peak strain has a polynomial (or linear) relationship with three studied variables. (4) For this polymer treated sand, the optimum mixing content is about 2%, and when the curing time reaches 24 h and above, it shows a better treatment effect. (5) The polymer forms an effective and stable three-dimensional membrane structure in the sand particles by adsorption, bonding and filling effects, and thus effectively improves the microstructure of sand. The proportion of changes in the types of polymers under load determines the strength, deformation capacity, and failure mode of treated sand, which is closely related to polymer content, curing time and dry density.
Polymer has broad application prospects in soil stabilization. However, there is currently little research on the strength and deformation characteristics of polymer treated soil, as well as the degree of influence of different influencing factors. In this work, a series of unconfined compression strength and shear strength tests were performed on a water-soluble polymer treated sand, and subsequently, the effects of polymer content, curing time and dry density on the strength and deformation characteristics of the treated sand were analyzed. Also, the degree of influence of the three research variables was elucidated using correlation analysis. And finally, the related mechanism of treated sand was revealed using SEM observations. The results show that: (1) The three studied variables significantly enhance the unconfined compression strength and shear strength, and the influence of polymer content and curing time on shear strength was mainly reflected in the cohesion. The strength of polymer treated sand is significantly and positively correlated with curing time, and moderately and positively correlated with polymer content and dry density. In addition, these relationships can be represented by a logarithmic function or linear function. (2) As the polymer content, curing time and dry density increase, the shear characteristics of treated sand change from shear hardening type to shear softening type, and the shear failure displacement of treated sand decreases gradually (as dry densities decreases). Also, its axial stress-strain curve shows obvious post-peak easing phenomenon and then produces obvious changes, and the compression failure pattern is dominated by bulging and accompanied by cracks, what's more, this pattern gradually changes from E-type to G-type (as dry densities decreases). (3) The deformation capacity of treated sand is strongly and positively correlated with curing time, moderately and positively correlated with dry density, while the correlation with polymer content is not significant. Additionally, the peak strain has a polynomial (or linear) relationship with three studied variables. (4) For this polymer treated sand, the optimum mixing content is about 2%, and when the curing time reaches 24 h and above, it shows a better treatment effect. (5) The polymer forms an effective and stable three-dimensional membrane structure in the sand particles by adsorption, bonding and filling effects, and thus effectively improves the microstructure of sand. The proportion of changes in the types of polymers under load determines the strength, deformation capacity, and failure mode of treated sand, which is closely related to polymer content, curing time and dry density.
2024, 41(8): 4287-4298.
doi: 10.13801/j.cnki.fhclxb.20240008.004
Abstract:
In order to study the mechanical properties of micro silicon powder (MP)-rubber/cement mortar, 16 sets of specimens were designed and analyzed by uniaxial compression test and impact test (separate Hopkinson pressure bar (SHPB)) for peak stress, peak strain, modulus of elasticity, impact strength, damage morphology and stress-strain curves of the specimens with different micro silicon powder dosage, rubber particle sizes and curing ages. The uniaxial compressive test shows that the addition of rubber particles decreases the compressive strength and modulus of elasticity of mortar specimens and increases the peak strain at the same age of maintenance, and the strength and modulus of elasticity of the specimens recover after the addition of micro silica powder. The impact resistance test shows that: Rubber will reduce the impact strength of mortar, but can improve the damage morphology of mortar, and micro silica powder not only enhances this improvement, but also improves the impact strength of rubber/cement mortar, in addition, after the addition of micro silica powder, the peak load of the stress-strain curve of the specimen will be shifted to the left due to the shortening of the elastic deformation and elasto-plastic deformation stages, but the damage stage is obviously prolonged.
In order to study the mechanical properties of micro silicon powder (MP)-rubber/cement mortar, 16 sets of specimens were designed and analyzed by uniaxial compression test and impact test (separate Hopkinson pressure bar (SHPB)) for peak stress, peak strain, modulus of elasticity, impact strength, damage morphology and stress-strain curves of the specimens with different micro silicon powder dosage, rubber particle sizes and curing ages. The uniaxial compressive test shows that the addition of rubber particles decreases the compressive strength and modulus of elasticity of mortar specimens and increases the peak strain at the same age of maintenance, and the strength and modulus of elasticity of the specimens recover after the addition of micro silica powder. The impact resistance test shows that: Rubber will reduce the impact strength of mortar, but can improve the damage morphology of mortar, and micro silica powder not only enhances this improvement, but also improves the impact strength of rubber/cement mortar, in addition, after the addition of micro silica powder, the peak load of the stress-strain curve of the specimen will be shifted to the left due to the shortening of the elastic deformation and elasto-plastic deformation stages, but the damage stage is obviously prolonged.
Structure and properties of chitosan enhanced cellulose nanofiber-montmorillonite composite membrane
2024, 41(8): 4299-4309.
doi: 10.13801/j.cnki.fhclxb.20231129.005
Abstract:
The way of mimicking the ordered "brick and mortar" structure in natural shells to prepare high-strength functional composite materials with cellulose and inorganic substances of which the interface bonding is the key to achieving ideal structure and performance is a potential excellent choice for producing naturally degradable packaging films. The single interfacial binding force between nanocellulose and montmorillonite results in insufficient mechanical properties. In this work, carboxymethyl cellulose nanofibers (CNFMG) and montmorillonite (MTM) nanosheets were used to prepare pearl layer films in which chitosan (CS) enhanced interface bonding through electrostatic interaction. The effects of electrostatic interactions between CS, CNFMG, and MTM on the structure, mechanical properties, and thermal stability of nanocomposites were studied. The results indicate that MTM in the composite membrane was orderly dispersed in nanosheet form between CNFMG networks. Compared with the CNFMG-MTM binary film, the tensile strength of the ternary film with the addition of CS reached 119.2 MPa, which doubled the strength. The fracture energy reached 10.9 MJ/m3, and the toughness was increased by 5.4 times. The composite film was semitransparent and had good UV shielding properties. The addition of CS also enhanced the thermal stability of the composite film. The research results of this article can provide ideas for the research and application of cellulose based pearl layer biomimetic materials.
The way of mimicking the ordered "brick and mortar" structure in natural shells to prepare high-strength functional composite materials with cellulose and inorganic substances of which the interface bonding is the key to achieving ideal structure and performance is a potential excellent choice for producing naturally degradable packaging films. The single interfacial binding force between nanocellulose and montmorillonite results in insufficient mechanical properties. In this work, carboxymethyl cellulose nanofibers (CNFMG) and montmorillonite (MTM) nanosheets were used to prepare pearl layer films in which chitosan (CS) enhanced interface bonding through electrostatic interaction. The effects of electrostatic interactions between CS, CNFMG, and MTM on the structure, mechanical properties, and thermal stability of nanocomposites were studied. The results indicate that MTM in the composite membrane was orderly dispersed in nanosheet form between CNFMG networks. Compared with the CNFMG-MTM binary film, the tensile strength of the ternary film with the addition of CS reached 119.2 MPa, which doubled the strength. The fracture energy reached 10.9 MJ/m3, and the toughness was increased by 5.4 times. The composite film was semitransparent and had good UV shielding properties. The addition of CS also enhanced the thermal stability of the composite film. The research results of this article can provide ideas for the research and application of cellulose based pearl layer biomimetic materials.
2024, 41(8): 4310-4323.
doi: 10.13801/j.cnki.fhclxb.20231218.003
Abstract:
In recent years, chloroquine phosphate (CQP) has been widely used as a specific drug for the treatment of COVID-19. Even after the epidemic ended, it still plays an important role because of its anti-inflammatory and anti-malaria capabilities. The widespread use of chloroquine phosphate poses serious potential hazards to the environment. Utilizing waste wood chips as resources, a nickel ferrite loaded biochar composite material (NiFe2O4@BC) with magnetic recovery was prepared by co precipitation anaerobic calcination method, and study the performance of activating peroxymonosulfate (PMS) to degrade CQP. The compositional structure, surface functional groups, and degree of graphitization of the NiFe2O4@BC composite were analyzed using various characterizations. Compared with unmodified fir sawdust biochar (BC), the loading of magnetic NiFe2O4 on the biochar resulted in an increase in the degree of graphitization of the composite, and an increase in the number of defective active sites, which led to a tremendous increase in the effectiveness of the removal of CQP. The effects of NiFe2O4@BC dosing, PMS concentration, initial pH of the solution, inorganic anions, and humic acid in the degradation of CQP were mainly investigated. Research shows that when NiFe2O4@BC under the conditions of 0.5 g/L dosage, 1.0 mmol/L PMS concentration, and 10 mg/L CQP concentration, the CQP removal rate reaches 89% in 120 min. The degradation of CQP is more favorable under acidic or alkaline conditions, and humic acid (HA) has a promoting effect on the degradation of CQP by NiFe2O4@BC-activated PMS. Quenching experiments confirm that •OH and 1O2 generated by the radical and non-radical pathways dominated the degradation of CQP by the NiFe2O4@BC/PMS system. Under the same conditions, it can achieve more than 80% degradation effect for many kinds of pollutants. In addition, the efficiency of CQP removal by activated PMS could still reach about 74% after NiFe2O4@BC was recycled 5 times. This study provides new strategies and reference significance for the efficient and green resource utilization of discarded fir sawdust.
In recent years, chloroquine phosphate (CQP) has been widely used as a specific drug for the treatment of COVID-19. Even after the epidemic ended, it still plays an important role because of its anti-inflammatory and anti-malaria capabilities. The widespread use of chloroquine phosphate poses serious potential hazards to the environment. Utilizing waste wood chips as resources, a nickel ferrite loaded biochar composite material (NiFe2O4@BC) with magnetic recovery was prepared by co precipitation anaerobic calcination method, and study the performance of activating peroxymonosulfate (PMS) to degrade CQP. The compositional structure, surface functional groups, and degree of graphitization of the NiFe2O4@BC composite were analyzed using various characterizations. Compared with unmodified fir sawdust biochar (BC), the loading of magnetic NiFe2O4 on the biochar resulted in an increase in the degree of graphitization of the composite, and an increase in the number of defective active sites, which led to a tremendous increase in the effectiveness of the removal of CQP. The effects of NiFe2O4@BC dosing, PMS concentration, initial pH of the solution, inorganic anions, and humic acid in the degradation of CQP were mainly investigated. Research shows that when NiFe2O4@BC under the conditions of 0.5 g/L dosage, 1.0 mmol/L PMS concentration, and 10 mg/L CQP concentration, the CQP removal rate reaches 89% in 120 min. The degradation of CQP is more favorable under acidic or alkaline conditions, and humic acid (HA) has a promoting effect on the degradation of CQP by NiFe2O4@BC-activated PMS. Quenching experiments confirm that •OH and 1O2 generated by the radical and non-radical pathways dominated the degradation of CQP by the NiFe2O4@BC/PMS system. Under the same conditions, it can achieve more than 80% degradation effect for many kinds of pollutants. In addition, the efficiency of CQP removal by activated PMS could still reach about 74% after NiFe2O4@BC was recycled 5 times. This study provides new strategies and reference significance for the efficient and green resource utilization of discarded fir sawdust.
2024, 41(8): 4324-4333.
doi: 10.13801/j.cnki.fhclxb.20240003.001
Abstract:
In order to efficiently adsorb enrofloxacin (EFA) in water, coconut shell biochar (BM-KOH-BC) was prepared by modifying coconut shell through ball milling and KOH activation, and in-depth research was conducted on the adsorption of EFA. BM-KOH-BC was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The results revealed that KOH activation and ball milling modification significantly improved the pore structure and specific surface area of BM-KOH-BC. Under optimized conditions (Initial EFA concentration is 80 mg·L−1, pH value is 7, temperature is 25℃, adsorbent dosage is 0.14 g·mg·L−1, stirring speed is 200 r/min, contact time under the conditions of 35 h), BM-KOH-BC showed good adsorption performance, with a removal rate of 77.4% and a maximum adsorption capacity of 481.1 mg·g−1. The adsorption process is consistent with the second-order kinetic model and Freundlich isotherm model. In addition, BM-KOH-BC still maintains efficient EFA removal rate after 5 adsorption-desorption cycles. This low-cost, efficient adsorption and recyclability feature makes BM-KOH-BC show potential application prospects in treating EFA in water bodies.
In order to efficiently adsorb enrofloxacin (EFA) in water, coconut shell biochar (BM-KOH-BC) was prepared by modifying coconut shell through ball milling and KOH activation, and in-depth research was conducted on the adsorption of EFA. BM-KOH-BC was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The results revealed that KOH activation and ball milling modification significantly improved the pore structure and specific surface area of BM-KOH-BC. Under optimized conditions (Initial EFA concentration is 80 mg·L−1, pH value is 7, temperature is 25℃, adsorbent dosage is 0.14 g·mg·L−1, stirring speed is 200 r/min, contact time under the conditions of 35 h), BM-KOH-BC showed good adsorption performance, with a removal rate of 77.4% and a maximum adsorption capacity of 481.1 mg·g−1. The adsorption process is consistent with the second-order kinetic model and Freundlich isotherm model. In addition, BM-KOH-BC still maintains efficient EFA removal rate after 5 adsorption-desorption cycles. This low-cost, efficient adsorption and recyclability feature makes BM-KOH-BC show potential application prospects in treating EFA in water bodies.
2024, 41(8): 4334-4343.
doi: 10.13801/j.cnki.fhclxb.20231211.001
Abstract:
In order to improve the surface hardness and wear resistance of TC4 titanium alloy, a high-speed nitriding treatment (HSNT) based on ultrafast high-temperature sintering (UHS) process was proposed. HSNT was applied to the surface of TC4 titanium alloy, and the microstructure of the sample was studied by X-ray diffractometer and scanning electron microscope. The mechanical properties of the sample were tested by Vickers microhardness tester and friction and wear test device. The modified layer can be formed on the surface of TC4 titanium alloy in 2 min. The modified layer consists of two parts. The outermost layer is the nitride layer, the thickness is about 10 μm, the average microhardness is HV0.1 973.55, and the main component is TiN. The sub-surface layer is nitriding layer, the thickness is also about 10 μm, the average microhardness is HV0.1 774.53, the cross-section microhardness overall shows a trend of ladder distribution. The friction and wear test shows that under 20 N load, the friction coefficient of TC4 with HSNT is 0.406, which is reduced by 24.4%, and the wear volume of TC4 with HSNT is 0.302 mm3, which is reduced by 86.7%. The friction coefficient and wear volume of TC4 with HSNT under different loads are always smaller than that of TC4 titanium alloy, and all increase with the increase of load. Under 20 N load, the wear mechanism of TC4 is mainly abrasive wear and oxidative wear, while the wear mechanism of TC4 with HSNT is mainly adhesive wear and oxidative wear. The performance of TC4 titanium alloy with HSNT has been significantly improved, making up for the shortcomings of low hardness and poor wear resistance of TC4.
In order to improve the surface hardness and wear resistance of TC4 titanium alloy, a high-speed nitriding treatment (HSNT) based on ultrafast high-temperature sintering (UHS) process was proposed. HSNT was applied to the surface of TC4 titanium alloy, and the microstructure of the sample was studied by X-ray diffractometer and scanning electron microscope. The mechanical properties of the sample were tested by Vickers microhardness tester and friction and wear test device. The modified layer can be formed on the surface of TC4 titanium alloy in 2 min. The modified layer consists of two parts. The outermost layer is the nitride layer, the thickness is about 10 μm, the average microhardness is HV0.1 973.55, and the main component is TiN. The sub-surface layer is nitriding layer, the thickness is also about 10 μm, the average microhardness is HV0.1 774.53, the cross-section microhardness overall shows a trend of ladder distribution. The friction and wear test shows that under 20 N load, the friction coefficient of TC4 with HSNT is 0.406, which is reduced by 24.4%, and the wear volume of TC4 with HSNT is 0.302 mm3, which is reduced by 86.7%. The friction coefficient and wear volume of TC4 with HSNT under different loads are always smaller than that of TC4 titanium alloy, and all increase with the increase of load. Under 20 N load, the wear mechanism of TC4 is mainly abrasive wear and oxidative wear, while the wear mechanism of TC4 with HSNT is mainly adhesive wear and oxidative wear. The performance of TC4 titanium alloy with HSNT has been significantly improved, making up for the shortcomings of low hardness and poor wear resistance of TC4.
2024, 41(8): 4344-4352.
doi: 10.13801/j.cnki.fhclxb.20240025.001
Abstract:
To improve the low longitudinal thermal conductivity of graphite film/aluminum composites, this study employed high-thermal diamond to penetrate the aluminum layer and establish a thermal conduction channel within the composites to effectively enhance their longitudinal thermal conductivity. To enhance the interface bonding between diamond and aluminum matrix. Tungsten coating was applied on the diamond surface using physical vapor deposition (PVD) technology. Subsequently, diamond-reinforced graphite film/aluminum composites were fabricated through fast hot pressing sintering (FHP) method. The influence of interfacial bonding and diamond volume fraction on the thermal conductivity of the composite were investigated. The results demonstrate that at a 10vol% volume fraction of W-coated diamond, the in-plane thermal conductivity reaches its peak value at 658 W/(m·K), which is 7% higher than that of an uncoated corundum reinforced composite. However, when the volume fraction of tungsten diamond plating exceeds 10vol%, the in-plane thermal conductivity shows a decreasing trend. The in-plane thermal conductivity is reduced to 535 W/(m·K) for composites with a high volume fraction of tungsten diamond coated (30vol%). Nevertheless, as the diamond volume fraction increases, more thermal conduction channels are formed within the composite leading to an increase in longitudinal thermal conductivity up to its highest value at 177 W/(m·K), which is 34% higher than that of uncoated diamond reinforced composites. The present study demonstrates that the incorporation of diamond thermal conduction channels between graphite film and aluminum effectively enhances the longitudinal thermal conductivity of composites.
To improve the low longitudinal thermal conductivity of graphite film/aluminum composites, this study employed high-thermal diamond to penetrate the aluminum layer and establish a thermal conduction channel within the composites to effectively enhance their longitudinal thermal conductivity. To enhance the interface bonding between diamond and aluminum matrix. Tungsten coating was applied on the diamond surface using physical vapor deposition (PVD) technology. Subsequently, diamond-reinforced graphite film/aluminum composites were fabricated through fast hot pressing sintering (FHP) method. The influence of interfacial bonding and diamond volume fraction on the thermal conductivity of the composite were investigated. The results demonstrate that at a 10vol% volume fraction of W-coated diamond, the in-plane thermal conductivity reaches its peak value at 658 W/(m·K), which is 7% higher than that of an uncoated corundum reinforced composite. However, when the volume fraction of tungsten diamond plating exceeds 10vol%, the in-plane thermal conductivity shows a decreasing trend. The in-plane thermal conductivity is reduced to 535 W/(m·K) for composites with a high volume fraction of tungsten diamond coated (30vol%). Nevertheless, as the diamond volume fraction increases, more thermal conduction channels are formed within the composite leading to an increase in longitudinal thermal conductivity up to its highest value at 177 W/(m·K), which is 34% higher than that of uncoated diamond reinforced composites. The present study demonstrates that the incorporation of diamond thermal conduction channels between graphite film and aluminum effectively enhances the longitudinal thermal conductivity of composites.
2024, 41(8): 4353-4365.
doi: 10.13801/j.cnki.fhclxb.20240012.002
Abstract:
In order to improve the intrinsic brittleness of Ti2AlNb alloy without sacrificing its high-temperature performance, a composite material was prepared by combining it with high-temperature titanium alloy TA15 using vacuum hot pressing. The effects of different hot pressing temperatures on the microstructure and tensile properties of Ti2AlNb/TA15 laminated composite materials were investigated. The results show that the pore defects in the interface layer gradually decrease with the increase of the hot pressing temperature. A defect-free metallurgical bonding interface can be achieved at temperatures of1050 ℃ and above. The thickness of the interface reaction layer increases with the rise of the hot pressing temperature. Under the diffusion conditions at 1050 ℃ and above, a transition layer of certain width formed between the reaction zone and the Ti2AlNb layers, which improve the properties of the interface bonding. Tensile tests indicate that the room and high-temperature tensile properties of the Ti2AlNb/TA15 laminated composite material are significantly improved compared with Ti2AlNb alloy. The laminated composite material under the hot pressing temperature condition of 1050 ℃ exhibits excellent comprehensive performance, with a high-temperature tensile strength and strain of 667.85 MPa and 16.2%, respectively.
In order to improve the intrinsic brittleness of Ti2AlNb alloy without sacrificing its high-temperature performance, a composite material was prepared by combining it with high-temperature titanium alloy TA15 using vacuum hot pressing. The effects of different hot pressing temperatures on the microstructure and tensile properties of Ti2AlNb/TA15 laminated composite materials were investigated. The results show that the pore defects in the interface layer gradually decrease with the increase of the hot pressing temperature. A defect-free metallurgical bonding interface can be achieved at temperatures of
2024, 41(8): 4366-4374.
doi: 10.13801/j.cnki.fhclxb.20231214.005
Abstract:
In order to obtain ceramic core with high chemical reaction resistance for titanium alloy investment casting, the Al powders were introduced into Y2O3-based ceramic core as the sintering aids, and then the modified ceramic core was prepared by hot injection molding. The effects of Al powder content on the densification characteristic, mechanical properties, microstructure and phase composition of Y2O3-based ceramic cores were studied. The results indicate that the sintering shrinkage and high temperature deflection of Y2O3-based ceramic core decrease with the increasing of Al powder content. The oxidation of Al element led to the expansion of the Al powders, which is beneficial to resist the shrinkage of Y2O3-based ceramic core during the sintering process. The densification of ceramic core is enhanced by liquid-phase sintering of Al powder melting and the interface reaction sintering of Al-Y2O3, as well as the diffusion sintering between Al2O3 and Y2O3 matrix. The formation of Al2Y4O9 crystals in matrix inhibits the secondary sintering of intergranular fine Y2O3 particles, which improves the high temperature creep resistance of the ceramic core. With a small amount of Al powder introducing, the Al2Y4O9 and Y2Al crystals are formed and then coated on the surface of the matrix Y2O3 particles, and the interfacial bonding strength is improved by the second phase strengthening. The Y2O3-based ceramic core modified by 2wt%Al powder, exhibits the optimal flexural strength about 34.38 MPa with a typical cleavage fracture, which is 49.15% higher than that of the ceramic core without Al powder. However, the expansion caused by excessive oxidation of Al powder can expands the distance between the ceramic particles. Therefore, the interfacial bonding strength of Y2O3-based ceramic core is weakened obviously, and then the ceramic core tends to fracture along the grain boundaries, resulting in the decrease of the bearing capacity under the load.
In order to obtain ceramic core with high chemical reaction resistance for titanium alloy investment casting, the Al powders were introduced into Y2O3-based ceramic core as the sintering aids, and then the modified ceramic core was prepared by hot injection molding. The effects of Al powder content on the densification characteristic, mechanical properties, microstructure and phase composition of Y2O3-based ceramic cores were studied. The results indicate that the sintering shrinkage and high temperature deflection of Y2O3-based ceramic core decrease with the increasing of Al powder content. The oxidation of Al element led to the expansion of the Al powders, which is beneficial to resist the shrinkage of Y2O3-based ceramic core during the sintering process. The densification of ceramic core is enhanced by liquid-phase sintering of Al powder melting and the interface reaction sintering of Al-Y2O3, as well as the diffusion sintering between Al2O3 and Y2O3 matrix. The formation of Al2Y4O9 crystals in matrix inhibits the secondary sintering of intergranular fine Y2O3 particles, which improves the high temperature creep resistance of the ceramic core. With a small amount of Al powder introducing, the Al2Y4O9 and Y2Al crystals are formed and then coated on the surface of the matrix Y2O3 particles, and the interfacial bonding strength is improved by the second phase strengthening. The Y2O3-based ceramic core modified by 2wt%Al powder, exhibits the optimal flexural strength about 34.38 MPa with a typical cleavage fracture, which is 49.15% higher than that of the ceramic core without Al powder. However, the expansion caused by excessive oxidation of Al powder can expands the distance between the ceramic particles. Therefore, the interfacial bonding strength of Y2O3-based ceramic core is weakened obviously, and then the ceramic core tends to fracture along the grain boundaries, resulting in the decrease of the bearing capacity under the load.
2024, 41(8): 4375-4385.
doi: 10.13801/j.cnki.fhclxb.20240202.001
Abstract:
The microstructure and properties of C/C-SiC composites prepared by reactive melt infiltration (RMI) are significantly affected by post-heat treatment. In order to study the effect and mechanism of post-heat treatment on the microstructure and mechanical properties of C/C-SiC composites prepared by RMI, the isothermal chemical vapor infiltration (CVI) process was used to deposit pyrolytic carbon matrix in the carbon fiber preform, and C/C porous bodies with a density of 1.2 g/cm3 were prepared by using natural gas as carbon source gas and nitrogen as carrier gas and dilution gas. Then C/C-SiC composites were prepared by reactive melt infiltration method. The effects of different post-heat treatment temperatures on the phase composition, internal stress and mechanical properties of C/C-SiC composites were studied. The prepared C/C-SiC composites were treated at1300 ℃, 1500 ℃ and 1700 ℃, respectively. The effects of post-high temperature heat treatment on the density, porosity, matrix composition, internal stress and bending properties of the C/C-SiC composites were investigated. The results show that after heat treatment at 1300 ℃, 1500 ℃ and 1700 ℃, the density of C/C-SiC composites decreases, the porosity increases, the content of SiC matrix increases, the distribution of SiC matrix becomes more extensive, and the residual Si content decreases significantly with large pores caused by residual Si volatilization. At 1300 ℃, 1500 ℃ and 1700 ℃, the bending strength increases first and then decreases. At 1500 ℃, the bending strength reaches a maximum of 296.52 MPa. With the increase of the post-treatment temperature, the bending modulus decreases, and at 1700 ℃, the bending strength decreases the most.
The microstructure and properties of C/C-SiC composites prepared by reactive melt infiltration (RMI) are significantly affected by post-heat treatment. In order to study the effect and mechanism of post-heat treatment on the microstructure and mechanical properties of C/C-SiC composites prepared by RMI, the isothermal chemical vapor infiltration (CVI) process was used to deposit pyrolytic carbon matrix in the carbon fiber preform, and C/C porous bodies with a density of 1.2 g/cm3 were prepared by using natural gas as carbon source gas and nitrogen as carrier gas and dilution gas. Then C/C-SiC composites were prepared by reactive melt infiltration method. The effects of different post-heat treatment temperatures on the phase composition, internal stress and mechanical properties of C/C-SiC composites were studied. The prepared C/C-SiC composites were treated at
2024, 41(8): 4386-4397.
doi: 10.13801/j.cnki.fhclxb.20231206.002
Abstract:
In this paper, the self-consistent clustering analysis (SCA) method was used to investigate the progressive damage behavior of 2D C/SiC under uniaxial compression load. The SCA method clusters the grid elements by strain concentration tensor, which greatly reduces the degree of freedom of the model and improves the computational efficiency of the model without significantly reducing the computational accuracy. The whole method consists of two stages: Offline and online. In the offline stage, the k-means algorithm was used to decompose and cluster the high-fidelity composite unit cells and calculate the interaction tensor between different clusters, and finally the reduced-order model was generated. At the online stage, the mechanical response was obtained by solving the discrete Lippmann-Schwinger equations based on the reduced-order model. The SCA method was applied to predict the compressive strength of 2D C/SiC. When the total number of clusters is 64, compared with the experiment, the calculation accuracy of the compressive strength solution is reduced by 1% compared with the traditional finite element method, but the overall calculation efficiency is improved by 34 times. When the clustering time spent in the offline stage is not considered, that is, the meso-structure of the material is known in advance to solve its mechanical behavior, the time of one-time online calculation is only 6 s, and the calculation efficiency is 104 times higher than that of the traditional finite element method. It has broad application prospects in the fields of rapid design of structural performance and rapid prediction of structural state.
In this paper, the self-consistent clustering analysis (SCA) method was used to investigate the progressive damage behavior of 2D C/SiC under uniaxial compression load. The SCA method clusters the grid elements by strain concentration tensor, which greatly reduces the degree of freedom of the model and improves the computational efficiency of the model without significantly reducing the computational accuracy. The whole method consists of two stages: Offline and online. In the offline stage, the k-means algorithm was used to decompose and cluster the high-fidelity composite unit cells and calculate the interaction tensor between different clusters, and finally the reduced-order model was generated. At the online stage, the mechanical response was obtained by solving the discrete Lippmann-Schwinger equations based on the reduced-order model. The SCA method was applied to predict the compressive strength of 2D C/SiC. When the total number of clusters is 64, compared with the experiment, the calculation accuracy of the compressive strength solution is reduced by 1% compared with the traditional finite element method, but the overall calculation efficiency is improved by 34 times. When the clustering time spent in the offline stage is not considered, that is, the meso-structure of the material is known in advance to solve its mechanical behavior, the time of one-time online calculation is only 6 s, and the calculation efficiency is 104 times higher than that of the traditional finite element method. It has broad application prospects in the fields of rapid design of structural performance and rapid prediction of structural state.
2024, 41(8): 4398-4407.
doi: 10.13801/j.cnki.fhclxb.20240018.002
Abstract:
The inter-laminar stress in multi-layer composite cylindrical structures can cause internal delamination, structural instability, etc. It is necessary to study the internal stress formation mechanism. An analytical model for prediction of the inter-laminar stress in multi-layer composite cylinders subjected to thermal loading was developed based on an anisotropic constitutive model and the plane stress assumption. The analytical model was validated by means of finite element analyses and a thermal expansion experiment performed on a composite cylinder. Using this validated model, the inter-laminar stress between layers and the thermal expansion behavior were investigated. Results show that the special geometric constraint of the cylinder itself plays an important role in the residual stress development. The thermal expansion behavior in the cylinders is much different compared to that in planer laminated composites. Due to the difference of modulus and coefficient of thermal expansion along hoop and radial direction, a significant inter-laminar tensile stress will generate during cooling down process. Furthermore, the hoop thermal expansion deformation shows an evident increasing trend from the inner layer to the outer layer. The hoop thermal expansion deformation in the inner layer is much smaller than that of the composite. With the increment of the cylinder thickness, the inter-laminar tensile stress, and the difference in coefficient of thermal expansion between inner layer and outermost layer increase. The developed model could be useful to disclose the stress-induced inter-laminar crack and optimize stress distribution in multi-layer composite cylinders.
The inter-laminar stress in multi-layer composite cylindrical structures can cause internal delamination, structural instability, etc. It is necessary to study the internal stress formation mechanism. An analytical model for prediction of the inter-laminar stress in multi-layer composite cylinders subjected to thermal loading was developed based on an anisotropic constitutive model and the plane stress assumption. The analytical model was validated by means of finite element analyses and a thermal expansion experiment performed on a composite cylinder. Using this validated model, the inter-laminar stress between layers and the thermal expansion behavior were investigated. Results show that the special geometric constraint of the cylinder itself plays an important role in the residual stress development. The thermal expansion behavior in the cylinders is much different compared to that in planer laminated composites. Due to the difference of modulus and coefficient of thermal expansion along hoop and radial direction, a significant inter-laminar tensile stress will generate during cooling down process. Furthermore, the hoop thermal expansion deformation shows an evident increasing trend from the inner layer to the outer layer. The hoop thermal expansion deformation in the inner layer is much smaller than that of the composite. With the increment of the cylinder thickness, the inter-laminar tensile stress, and the difference in coefficient of thermal expansion between inner layer and outermost layer increase. The developed model could be useful to disclose the stress-induced inter-laminar crack and optimize stress distribution in multi-layer composite cylinders.
2024, 41(8): 4408-4417.
doi: 10.13801/j.cnki.fhclxb.20240019.004
Abstract:
The phase field method, recognized for its effectiveness in fracture analysis, particularly of isotropic and composite materials, remains a key research focus when considering the intricacies of fractures in anisotropic materials and their composites. In this study, a refined approach to decomposing elastic strain energy was presented. This method excludes the compressive volumetric strain energy influence on crack propagation and accounts for asymmetries in material constitutive relationships under tension and compression. Leveraging this, a tailored phase field analysis model for orthotropic material fractures was constructed. To validate the model's robustness and applicability, this work conducted analyses on unidirectional opening plates made of isotropic and orthotropic materials, focusing on tensile and shear boundary conditions. For composite plates with unidirectional fiber reinforcement, the Hashin criterion was incorporated to refine the quantification of damage-induced crack driving forces. This facilitated accurate simulations of tensile behavior in composite plates with varying carbon fiber orientations. Our findings demonstrate the profound capability of our theoretical framework in simulating crack propagation in anisotropic materials and unidirectional fiber-reinforced composites. The predicted crack propagation paths align with those from established models for both isotropic and orthotropic materials, attesting to the model's fidelity. Within composites, we observed a strong alignment between crack propagation and fiber orientation, highlighting a robust correlation between our predictions and experiment results.
The phase field method, recognized for its effectiveness in fracture analysis, particularly of isotropic and composite materials, remains a key research focus when considering the intricacies of fractures in anisotropic materials and their composites. In this study, a refined approach to decomposing elastic strain energy was presented. This method excludes the compressive volumetric strain energy influence on crack propagation and accounts for asymmetries in material constitutive relationships under tension and compression. Leveraging this, a tailored phase field analysis model for orthotropic material fractures was constructed. To validate the model's robustness and applicability, this work conducted analyses on unidirectional opening plates made of isotropic and orthotropic materials, focusing on tensile and shear boundary conditions. For composite plates with unidirectional fiber reinforcement, the Hashin criterion was incorporated to refine the quantification of damage-induced crack driving forces. This facilitated accurate simulations of tensile behavior in composite plates with varying carbon fiber orientations. Our findings demonstrate the profound capability of our theoretical framework in simulating crack propagation in anisotropic materials and unidirectional fiber-reinforced composites. The predicted crack propagation paths align with those from established models for both isotropic and orthotropic materials, attesting to the model's fidelity. Within composites, we observed a strong alignment between crack propagation and fiber orientation, highlighting a robust correlation between our predictions and experiment results.
2024, 41(8): 4418-4433.
doi: 10.13801/j.cnki.fhclxb.20240015.002
Abstract:
Based on bilinear constitutive relationship, a cohesive model considering fatigue damage was established. Integrating with finite element analysis technology, the numerical analysis method of delamination propagation behavior of composite laminates was developed to simulate the mode II delamination propagation behavior of plane woven composite laminates under static and fatigue loading. The simulated load-displacement curve under quasi-static loading has good agreement with the experimental results. The simulated delamination propagation rate-strain energy release rate curve under fatigue loading is also in good agreement with the experimental results. Thus, the cohesive model considering fatigue damage has been validated. On this basis, the fatigue failure criteria for plane woven composites were established. Then the residual life prediction method of plane woven composite laminates with initial delamination damage was developed by integrating with the intralaminar progressive fatigue damage model. Using the developed method, the residual life and fatigue damage propagation of laminates with initial delamination damage were predicted, showing good correlation with the experimental results. In addition, the simulation results indicate that the fatigue damage initiates from the initial delamination damage which then propagates to the edges. The fatigue damage in both warp and weft directions appear early within the two layers of (0°/90°) adjacent to the initial delamination damage. And more damage occurs within the (0°/90°) layers than the (±45°) layers in general. Finally, the (0°/90°) layers show warp damage dominated failure mode while the (±45°) layers show weft damage dominated failure mode, and large area of damage appear at all the interlaminar interfaces.
Based on bilinear constitutive relationship, a cohesive model considering fatigue damage was established. Integrating with finite element analysis technology, the numerical analysis method of delamination propagation behavior of composite laminates was developed to simulate the mode II delamination propagation behavior of plane woven composite laminates under static and fatigue loading. The simulated load-displacement curve under quasi-static loading has good agreement with the experimental results. The simulated delamination propagation rate-strain energy release rate curve under fatigue loading is also in good agreement with the experimental results. Thus, the cohesive model considering fatigue damage has been validated. On this basis, the fatigue failure criteria for plane woven composites were established. Then the residual life prediction method of plane woven composite laminates with initial delamination damage was developed by integrating with the intralaminar progressive fatigue damage model. Using the developed method, the residual life and fatigue damage propagation of laminates with initial delamination damage were predicted, showing good correlation with the experimental results. In addition, the simulation results indicate that the fatigue damage initiates from the initial delamination damage which then propagates to the edges. The fatigue damage in both warp and weft directions appear early within the two layers of (0°/90°) adjacent to the initial delamination damage. And more damage occurs within the (0°/90°) layers than the (±45°) layers in general. Finally, the (0°/90°) layers show warp damage dominated failure mode while the (±45°) layers show weft damage dominated failure mode, and large area of damage appear at all the interlaminar interfaces.
