基于弹塑性损伤本构模型的复合材料层合板破坏荷载预测

在连续损伤力学和塑性力学框架内,建立一个同时考虑塑性效应和损伤累积导致材料属性退化的复合材料弹塑性损伤本构模型。基于最近点投影回映算法,开发本构模型的应变驱动隐式积分算法以更新应力及与解答相关的状态变量,并推导与所开发算法相应的数值一致性切线刚度矩阵,保证有限元分析采用NewtonRaphson迭代法解答非线性问题的计算效率。采用断裂带模型对已开发的本构模型软化段进行规则化,以减轻有限元分析结果的网格相关性问题。对损伤变量进行粘滞规则化,并推导出相应的粘滞规则化数值一致性切线刚度张量,解决了在有限元隐式计算程序中采用含应变软化段本构关系的数值分析由于计算困难而提前终止的问题。开发包含数值积分算法的用户材料子程序UMAT,并嵌于有限元程序Abaqus v6.14中。通过对力学行为展现显著塑性效应的AS4/3501-6V型开口复合材料层合板的渐进失效分析,验证本文提出的材料本构模型的有效性。结果显示,预测结果与已报道的试验结果吻合良好,并且预测精度高于其他已有弹性损伤模型。表明已建立的弹塑性损伤本构模型能够准确预测力学行为,展现显著塑性效应的复合材料层合板的破坏荷载,为其构件和结构设计提供一种有效的分析方法。

Failure loads prediction of composite laminates using a combined elastoplastic damage model

Based on the framework of continuum damage mechanics and plasticity theory,a combined elastoplastic damage model which takes into account the plasticity effects and material properties degradation due to damage development was developed.Based on the closest point projection return mapping algorithm,a strain-driven implicit integration algorithm for the model was developed to update stresses and solution dependent state variables.A tangent stiffness tensor consistent with the developed numerical algorithm was derived to ensure the computational efficiency of Newton-Raphson method in the finite element analysis.In order to alleviate mesh dependency of finite element analysis results,the "Crack Band Theory" was applied to regularize the softening branch of the material model.Also,in order to avoid premature abortion of numerical analysis using strain softening material models based on implicit procedures,a viscous regularization scheme was applied to the damage parameters.Accordingly,the regularized numerical consistent tangent tensor was derived.User-defined material subroutine UMAT containing the numerical integration algorithm was coded and implemented in finite element procedure Abaqus v6.14.The efficiency of the material constitutive model was demonstrated through progressive failure analysis of a V-notched AS4/3501-6 composite laminate,the mechanical behavior of which demonstrates significant plasticity effects.The predicted results agree well with the experimental data reported in the literature and the developed model outperforms other existing elastic-damage models in predicting the failure loads.The result shows that the combined elastoplastic damage model can predict the mechanical behavior of composite materials which exhibit pronounced plasticity effects with sufficient accuracy.The proposed approach provides an efficient method for composite component and structural design.