基于组合单元的层压复合材料三维应力分析

3D stress analysis of composite laminate based on a kind of interfacial element

  • 摘要: 为了分析层压复合材料层间特性,推导了将刚性元-弹簧元相结合的离散型界面单元的刚度矩阵。建立了层压板的准三维模型,即将Mindlin板单元应用于层压板的各子层,层间作用则利用上述界面单元来模拟。通过弯曲板元计算子层面内应力,通过界面单元的弹簧力确定层间应力。对受面内拉伸的多向层压板条进行了应力分析,与使用商业软件三维实体模型计算得到的层间和面内应力对比,结果表明准三维模型的计算结果合理。这种新型界面单元的优点是可用来表征层间损伤,并且能通过对弹簧刚度的消减来模拟分层损伤的演变。

     

    Abstract: An interfacial element derived from the combination of two rigid elements and three spring elements was developed to analyze the interfacial properties of composite laminates. The 3D stress distribution of a laminate was determined by means of a quasi-3D finite element mesh,in which each layer of the laminate is modeled by Mindlin plate elements,and the cohesion among the neighborhood layers is simulated by the interfacial elements,for which none of the additional nodes and degrees of freedom are needed. The in-plane stress can be determined from the plate elements,and the interlaminar stress can be confirmed from the spring force in interfacial elements. As an example,a rectangular multidirectional laminate under tension was analyzed. The 3D stress determined correlates well with that of a 3D solid element model. With the recommended interfacial elements, the delamination damage and its evolution can be easily simulated by the degradation of the corresponding spring stiffness.

     

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