拉压异性纤维增强树脂基复合材料弹塑性问题的有限元分析

为了对复杂的非线性问题进行便捷求解,首先提出了考虑拉压异性的纤维增强树脂基复合材料统一非线性本构模型;然后,在此基础上进一步导出了本构模型的三维表现形式,以适用于非线性有限元分析工具的开发;随后,利用有限元软件ABAQUS提供的用户自定义子程序UMAT,自编了在二维和三维情况下的弹塑性应力分析程序;最后,应用程序对复合材料单向板和复合材料斜交板在偏轴拉伸/压缩下应力-应变曲线的预测与测试结果进行了比较,探讨了复合材料悬臂梁的弹塑性问题,并分析和比较了有无考虑拉压异性情况下应力分布和挠度响应的差异。结果表明:运用所提出的本构模型对考虑拉压不对称问题的弹塑性变形分析十分有效,这一本构模型有望成为实用数值分析工具,进而指导工程实践。

Finite element analysis of elastic-plastic problems for strength-differential fiber reinforced resin matrix composites

In order to solve the complex nonlinear problem conveniently, the unified nonlinear constitutive model considering strength-differential effects of fiber reinforced resin matrix composites was proposed firstly. Then, the three-dimensional expression form of the constitutive model was deduced ulteriorly on the basis to be appropriate for the development of nonlinear finite element analysis tool. After that, using user-defined subroutine UMAT which was provided by finite element program ABAQUS, elastic-plastic stress analysis program in cases of two-dimensional and three-dimensional was self-compiled. Finally, the prediction and testing results of stress-strain curves for unidirectional composite laminates and angle-ply composite laminates under off-axis tension/compression were compared using the program, the elastic-plastic problems of composite cantilever beams were discussed, and the differences of stress distribution and deflection response between the cases of with and without considering strength-differential effects were analyzed and compared. The results show that using the proposed constitutive model to analyze the elastic-plastic deformation considering tension and compression asymmetric problems is quite efficient. The constitutive model is expected to become the practical numerical analysis tool, thus guides engineering practices.