1985 Vol. 2, No. 1
1985, 2(1): 1-14.
Abstract:
This psper proposes a theoretical method to analyza the buckling and postbuckling bachavior of multi-laverel fiber reinforeed composite cvlindical shells under uniform axial or hedrostatic compression. The influences of shear nonlincarity of the composite material and the initial imperfection of the shell geometry are taken into account. For the competation of the critical form potential energy method is used. Numerical results are given for boron epoxy temposite cylindrical shells with various fiber orientation and diffreent layer numbers. Results show that the shear nonlinearity of the composite materials and the initial imperfections of the shells are both important for the composite and postbackling behavior of the composite cylineleical shells.
This psper proposes a theoretical method to analyza the buckling and postbuckling bachavior of multi-laverel fiber reinforeed composite cvlindical shells under uniform axial or hedrostatic compression. The influences of shear nonlincarity of the composite material and the initial imperfection of the shell geometry are taken into account. For the competation of the critical form potential energy method is used. Numerical results are given for boron epoxy temposite cylindrical shells with various fiber orientation and diffreent layer numbers. Results show that the shear nonlinearity of the composite materials and the initial imperfections of the shells are both important for the composite and postbackling behavior of the composite cylineleical shells.
1985, 2(1): 15-21.
Abstract:
The dynamic mechauical properties of polymerisation proccsscs and its polymers of bis(4-(4-ethynylphenoxy)pbeoyl) ketone were investigated by torsional braid analysis (TBA) and infrared spectroscopy.Results showed that the multiple transitions including the melting,low-and high-temperature reaction of oligomcr,glass transition and decompositio reaction of its polymer could be characterized in the TBA spectra.The glass transition temperature of polymers depends upon the conditions of polymerization-curing.
The dynamic mechauical properties of polymerisation proccsscs and its polymers of bis(4-(4-ethynylphenoxy)pbeoyl) ketone were investigated by torsional braid analysis (TBA) and infrared spectroscopy.Results showed that the multiple transitions including the melting,low-and high-temperature reaction of oligomcr,glass transition and decompositio reaction of its polymer could be characterized in the TBA spectra.The glass transition temperature of polymers depends upon the conditions of polymerization-curing.
1985, 2(1): 23-37.
Abstract:
In the Paper, a set of infinite poiwerr series of particular forms to satisfy certain special con litious is cliosen as trial fuuction of the displzcement functions.The scheme of solution by the methoa of weighed residual is applied to the bimodulus composite materials for the first time.Good agreement is obtained between the solutions of MWR and exact closed-form for a simply supporsed cross-plied thin rectangular plate subjected to a sinusoidally normal pressure in the neutral surafce positions, displacements, stress couples and stress resultants.Thereby the method can also be applied to other case of laminates of bimodulus eomposite materials.
In the Paper, a set of infinite poiwerr series of particular forms to satisfy certain special con litious is cliosen as trial fuuction of the displzcement functions.The scheme of solution by the methoa of weighed residual is applied to the bimodulus composite materials for the first time.Good agreement is obtained between the solutions of MWR and exact closed-form for a simply supporsed cross-plied thin rectangular plate subjected to a sinusoidally normal pressure in the neutral surafce positions, displacements, stress couples and stress resultants.Thereby the method can also be applied to other case of laminates of bimodulus eomposite materials.
1985, 2(1): 38-46.
Abstract:
A general fornula for calculating the mandrel turning angle hetwecn any two points on the geodesie dome is given.The precision solutions and computational results of turning angles on sphere, isotensoid,ellipsoid and cone are presented.
A general fornula for calculating the mandrel turning angle hetwecn any two points on the geodesie dome is given.The precision solutions and computational results of turning angles on sphere, isotensoid,ellipsoid and cone are presented.
1985, 2(1): 47-61.
Abstract:
Based on the analysis aralcgcts to that of Reference [10], an elasticity solution for a double-layered transversely isctropic circular cylindrical shell with its erds simply-supported and under the axispn metric loads is pressented. Through numerical computations, graphs are plotted to show the effects of varicns elastic mcdulus ratios and the noradimensional shape parameters on the dis tribution of the interlaminar stresses for the case that a prescribed uniform axial strain is applied to LLe erds of the shell in addition to the lateral pressure.
Based on the analysis aralcgcts to that of Reference [10], an elasticity solution for a double-layered transversely isctropic circular cylindrical shell with its erds simply-supported and under the axispn metric loads is pressented. Through numerical computations, graphs are plotted to show the effects of varicns elastic mcdulus ratios and the noradimensional shape parameters on the dis tribution of the interlaminar stresses for the case that a prescribed uniform axial strain is applied to LLe erds of the shell in addition to the lateral pressure.
1985, 2(1): 63-71.
Abstract:
The serves expressions of stresses and displace ments of both anisotropic and unidirectional fiber-reinforced com posite plates with cracks are derived.Each term of the series can satisfy the equilibrium equations,the equation of compatibility and boundary conditions of forces on the crack suifaces and other boundary conditions of forces can be satisfied by the variationat method to deter mine the stress intensity factors. Finally, the computational results about strip tension,compact tension and three point bending specimens are presented.
The serves expressions of stresses and displace ments of both anisotropic and unidirectional fiber-reinforced com posite plates with cracks are derived.Each term of the series can satisfy the equilibrium equations,the equation of compatibility and boundary conditions of forces on the crack suifaces and other boundary conditions of forces can be satisfied by the variationat method to deter mine the stress intensity factors. Finally, the computational results about strip tension,compact tension and three point bending specimens are presented.
1985, 2(1): 72-79.
Abstract:
In structural design we usually use a well-known criterion,σ≤[σ].However, the maximum stress only covers a very small region in the structure and this region does not always coincide with the weakest point of the material used.The strength characteristics of the advanced composites are the linear elasticity and the large scatter band of strength so that the conventional criterion does not meet the design requirements very well. From the statistical point of veiw this problem is discussed and treated in this paper, which includes four aspects:the scatter band of strength,series model,parallel model and some simple structural applications.
In structural design we usually use a well-known criterion,σ≤[σ].However, the maximum stress only covers a very small region in the structure and this region does not always coincide with the weakest point of the material used.The strength characteristics of the advanced composites are the linear elasticity and the large scatter band of strength so that the conventional criterion does not meet the design requirements very well. From the statistical point of veiw this problem is discussed and treated in this paper, which includes four aspects:the scatter band of strength,series model,parallel model and some simple structural applications.
1985, 2(1): 80-85.
Abstract:
Monofilameut contact angle meter has been used to measure the critical surface tension of glass fiber treated by different cooupling agents.Because the critical surface tension of solid is a plysico-chemical parameter denoter the surface property of solid and it is only dependent on the nature of cover bet indepemlent of the internal constitution of glass filer.It is found that glass fibers trested lay different coupling agents have different surfere tensions, the order is as follows: 7114>KH550>A151 The components of coupling agent sedimeuted on surface of class fiber hive different effects on wetting property.
Monofilameut contact angle meter has been used to measure the critical surface tension of glass fiber treated by different cooupling agents.Because the critical surface tension of solid is a plysico-chemical parameter denoter the surface property of solid and it is only dependent on the nature of cover bet indepemlent of the internal constitution of glass filer.It is found that glass fibers trested lay different coupling agents have different surfere tensions, the order is as follows: 7114>KH550>A151 The components of coupling agent sedimeuted on surface of class fiber hive different effects on wetting property.
1985, 2(1): 86-92.
Abstract:
Contact laws for SMC composites under loading and naloading are established by the steel hall indentation testing.With these lays integrated with Mindlin's plate theory, stress waves at each paint iu SMS-R50 composite panels can be calculated using fiaite element method.The computional results of strain histeries are compared with experimendal data aad are proved to be acceptable.
Contact laws for SMC composites under loading and naloading are established by the steel hall indentation testing.With these lays integrated with Mindlin's plate theory, stress waves at each paint iu SMS-R50 composite panels can be calculated using fiaite element method.The computional results of strain histeries are compared with experimendal data aad are proved to be acceptable.
1985, 2(1): 93-100.
Abstract:
The damage accumulation and the failure mechanism in notched graphite/epoxy laminates have been iwestigatcd by employing penetrant enhanced X-ray radiography. This method is reliable and with the help of it where the damage takes place and how the damage zone expands can be observed clearly hsherimental results indirrte that the damage zone erpanding in the vioinity of retch tip is characteristic of failme the laminates and this damage zpne takes the from of matrix crackining,local delamination hetween plies and some fibers breaking.
The damage accumulation and the failure mechanism in notched graphite/epoxy laminates have been iwestigatcd by employing penetrant enhanced X-ray radiography. This method is reliable and with the help of it where the damage takes place and how the damage zone expands can be observed clearly hsherimental results indirrte that the damage zone erpanding in the vioinity of retch tip is characteristic of failme the laminates and this damage zpne takes the from of matrix crackining,local delamination hetween plies and some fibers breaking.
1985, 2(1): 101-106.
Abstract:
The United States AirForce,Army, Navy and NASA research activities and progress in mechanics of composite materials are summarized.Tne research activities include:1)Damage Mechanics, 2) Fracture Mechanics,3)Fatigue,4) Delamination and 5) Effects of Mechanical Repomse of Composites.
The United States AirForce,Army, Navy and NASA research activities and progress in mechanics of composite materials are summarized.Tne research activities include:1)Damage Mechanics, 2) Fracture Mechanics,3)Fatigue,4) Delamination and 5) Effects of Mechanical Repomse of Composites.
