T800碳纤维/PEEK热塑性复合材料的拉伸与剪切失效行为研究

Study on tensile and shear failure behavior of T800 carbon fiber/PEEK thermoplastic composites

采用T800碳纤维/聚醚醚酮(T800/PEEK)预浸料,以高温、模压方式制备了热塑性单向复合材料,通过拉伸、面内剪切试验方法对其模量和强度进行了测试分析,得到了不同载荷形式作用下的宏观失效破坏模式。针对T800/PEEK复合材料的微细观结构特点,建立了有限元代表性体积单元模型(RVE)和碳纤维、PEEK基体以及纤维/基体界面三种材料的本构关系,基于渐进损伤失效模型和内聚力模型得到了单轴拉伸/压缩、面内剪切载荷作用下单元模型的应力应变曲线和微细观失效模式。相比于试验测试结果,有限元模型预测得到的拉伸模量/强度相差最大为11%,剪切模量/强度相差最大为5%。

Based on the prepreg of T800 carbon fiber/polyether ether ketone(T800/PEEK),the thermoplastic unidirectional composites was prepared by means of high temperature and mould pressing.The modulus and strength of the materials were tested and analyzed by tensile and in-plane shear tests,and the failure modes under different loads were obtained.According to the micro-structural characteristics of T800/PEEK composites,the finite representative volume element model(RVE)and the constitutive relations of fiber,PEEK matrix and fiber/matrix interface were established.Based on the progressive loss failure model and the cohesive force model,the stress-strain relations and failure models of the unicellular model under uniaxial tensile/compression and in-plane shear load were studied.Compared to the experimental results,the maximum difference of tensile modulus/strength obtained by finite element predictions is 11%,the maximum difference of shear modulus/strength is 5%.