TZ300碳纤维束在不同应变率下的拉伸强度性能

Tensile properties of TZ300 carbon fiber bundles at different strain rates

  • 摘要: 为探究无基体约束条件下碳纤维束在不同应变率下的拉伸力学行为,本文基于纤维束强度的Weibull统计理论,建立了碳纤维束的统计损伤本构模型。采用电子万能试验机、自制单轴气动冲击装置及霍普金森拉杆装置,系统开展了TZ300碳纤维束在准静态( 2.7\times 10^-4\;\texts^-1 )、中应变率( 3\;\texts^-1 )及高应变率( \text470 s^-1 )下的拉伸试验,获取了各应变率下的应力-应变曲线,并分析了其力学响应特征。结果表明:在本试验所涵盖的应变率范围内,TZ300碳纤维束均呈现脆性断裂特征,其拉伸强度未表现出明显的应变率相关性,属应变率不敏感材料。该纤维束的强度统计特性服从单Weibull分布,其统一的Weibull参数:形状参数 \beta =4.52 ,尺度参数 \sigma _0\text=4.8\;GPa 。所建本构模型能够较好地描述其在不同应变率下的损伤演化与应力-应变关系。研究结果可为建立简化的、非应变率相关的碳纤维微观代表性体积单元(RVE)数值模型提供直接依据,对推动纺织碳纤维复合材料在多应变率工况下的工程应用具有参考价值。

     

    Abstract: To investigate the tensile mechanical behavior of carbon fiber tows without matrix confinement under different strain rates, a statistical damage constitutive model of the carbon fiber tow was established based on the Weibull statistical theory of fiber bundle strength. Tensile tests of TZ300 carbon fiber tows at quasi-static ( 2.7\times 10^-4\;\texts^-1 ), intermediate ( 3\;\texts^-1 ), and high ( \text470 s^-1 ) strain rates were systematically conducted using an electronic universal testing machine, a self-developed uniaxial pneumatic impact device, and a Hopkinson tensile bar apparatus. The stress–strain curves at each strain rate were obtained, and the corresponding mechanical response characteristics were analyzed. The results indicated that, within the strain rate range covered in the experiments, the TZ300 carbon fiber tows exhibited brittle fracture behavior, and their tensile strength showed no significant strain-rate dependence, indicating that the material is strain-rate insensitive. The statistical strength characteristics of the fiber tow obey a single Weibull distribution, with the unified Weibull parameters: shape parameter \beta =4.52 and scale parameter \sigma _0\text=4.8\;GPa . The proposed constitutive model can well describe its damage evolution and stress-strain relationship at different strain rates. The findings provide a direct basis for establishing simplified, strain-rate-independent numerical models of carbon fiber at the microscale representative volume element (RVE) level, and offer valuable references for promoting the engineering application of textile carbon fiber composites under multi-strain-rate conditions.

     

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