热塑性复合材料的黏塑性有限元法

Viscoplastic Finite Element Method for Thermoplastic Composites

为了对热塑性复合材料AS4/PEEK进行黏塑性分析,基于北京某公司的有限元自动生成软件系统(FEPG),对反映AS4/PEEK非线性行为和应变速率相关行为的三维黏塑性模型编制了相应的黏塑性有限元程序,计算了不同铺设角(15°、30°、45°和90°)的单层板在应变率分别为1×10-5s-1和0.1s-1下的应力应变曲线,在纵向等应变率加载条件下,研究了差分系数θ分别为0、0.5、0.65、0.85和1以及时间步长△t分别为0.001s、0.002s和0.003s的变化对计算结果的影响.研究结果表明,有限元程序所得到的应力应变曲线与实验结果基本吻合,验证了程序实现的正确性;不同的差分系数对所得到的应力-应变曲线影响甚微,时间步长对计算结果影响较弱.

In order to carry out viscoplastic analysis of the thermoplastic composites AS4/PEEK, based on the finite element program generator（FEPG） of Beijing Feijian Software Cooperation, the three-dimensional viscoplasticity model which can simulate the nonlinear behavior and the strain rate dependence behavior of AS4/PEEK is introduced into this system and the relative finite element procedure is developed. The stress-strain curves of different unidirectional AS4/PEEK composites（ 15° ,30° ,45° ,90°） for the strain rate of 0.1 s^-1 and 1 × 10^-5 s^-1 are computed and presented. Under the equal-strain-rate loading conditions in the longitudinal direction, the effects of the different coefficient（θ is 0,0.5,0.65,0.85 and 1 respectively）and time step length （△t is 0. 001,0. 002 and 0. 003 respectively）on the computation results are studied. The results show that the finite element calculations are very close to the experimental results, which verifies the precision of the developed programs, and that the change of the coefficient affects the obtained stress-strain curves little and the time step length affects the computation results very slightly.