考虑纤维初始位错的复合材料轴向压缩性能
Longitudinal compressive properties of composites considering fiber initial misalignment

通过试验及模拟对复合材料的轴向压缩失效过程进行了研究。试验中，采用高速摄像机对失效过程进行捕捉，并对最终破坏模式进行光学显微镜分析。基于纤维初始位错、纤维随机强度及基体Ducker-Prager塑性本构，通过有限元软件ABAQUS建立了复合材料轴向压缩的有限元模型，并对比分析剪切型及拉伸型两种不同初始位错模型的模拟结果。研究结果表明，复合材料轴向压缩包含弹性变形及塑性变形阶段，离散的纤维基体二维有限元模型能够有效模拟压缩的渐进损伤过程，且模拟结果与试验结果相吻合。复合材料轴向压缩强度是纤维初始位错及塑性基体剪切屈服共同作用的结果，其随着纤维初始位错幅值的减小、波长的增加及纤维体积分数的增加而增加。 Response of carbon fiber composites under longitudinal compression were researched using the tool of compressive test and finite element simulation. The progressive damage during the loading process was detected with high speed camera and the final failure mode was observed by optical microscope. Based on fiber initial misalignment and matrix Drucker-Prager plastic constitutive model, finite element models were established using ABAQUS to analyze the results of different fiber initial misalignment models including shear mode and extensional mode. Results show that elastic and plastic deformations are both found during the longitudinal compression. Discrete two-dimensional fiber-matrix finite element model can efficiently simulate the process of compression, which corresponds to the test results. Compressive strength of composites depends on the fiber initial misalignment and shear yielding of plastic matrix. And it increases with the decreasing of fiber initial misalignment amplitude, increasing of fiber initial misalignment wavelength, as well as the increasing of fiber volume fraction.