Glass/Epoxy复合材料叠层板面内剪切连续损伤模型

为确定S2玻璃纤维/环氧树脂(S2-Glass/Epoxy) 叠层复合材料面内剪切应力-应变关系,对S2-Glass/Epoxy 叠层复合材料面内剪切拉伸载荷下的弹、塑性连续损伤本构模型及应用进行了研究。基于平面应力状态下的连续损伤力学模型,通过典型面内剪切拉伸实验,分别建立了忽略塑性应变和考虑塑性应变的两种连续损伤力学(CDM)模型,并确定相关参数。通过ABAQUS/Explicit 用户子程序VUMAT接口,分别采用两种CDM模型对S2-Glass/Epoxy 叠层复合材料面内剪切拉伸实验进行有限元数值计算,与实验结果对比,验证模型可靠性,并分析单元类型对有限元计算结果的影响。研究结果表明: 忽略塑性应变的CDM模型可以很好地预测复合材料面内剪切失效强度,但不能较好地预测其非线性力学响应; 考虑塑性应变,将塑性硬化与损伤耦合后的CDM模型则能较好的预测复合材料非线性力学响应和面内剪切失效强度; 该平面应力状态下建立的CDM模型可用于壳单元进行复合材料有限元数值计算,横向剪切作用导致传统壳单元数值计算的载荷位移曲线略低于平面应力单元计算结果; 减缩积分算法有利于提高有限元数值计算结果的准确性。

Continuum damage mechanics model of glass/epoxy composite laminate under in-plane shear loading

In order to investigate the in-plane shear behaviour of S2-glass/epoxy composite laminate, continum damage mechanics (CDM) model involving elasticity and plasticity for S2-glass/epoxy laminate under in-plane shear loading was studied in this paper. Typical in-plane tensile shear tests of the composite were conducted, two types of CDM models were established based on the plane stress assumption and the parameters were identified. The former CDM model considered no plasticity while the later one did. Both two CDM models were coded to VUMAT through ABAQUS/Explicit, finite element analysis (FEA) for in-plane shear behaviour of the composite was conducted by them following experimental tests. The results of FEA were compared with experiments and the influence of plasticity on the in-plane shear behaviour of the composite was discussed. Element types on the results of FEA were also analyzed. The results show that the CDM model considering no plasticity can exactly predict the failure strength of S2-glass/epoxy composite under in-plane shear loading, but it can not well predict the nonlinear mechanical behaviour. However, when coupled with isotropic plasticity criteria, the CDM model can perfectly predict the nonlinear mechanical behavior, and the result of failure strength is also acceptable compared with the experimental results. The CDM models can also be used for FEA simulation by shell elements, but the results of load-deflection curve are a little lower than that using plane stress elements because of the transverse shear behaviour of shell elements. Moreover, reduced integration method is found to be beneficial for FEA simulation.