一种层压复合材料组合界面单元及有限元模型

 为了高效模拟计算复合材料层合板的层间损伤,提出了一种由刚性元和零厚度的内聚力单元组合而成的新型组合界面单元,并提出了以弯曲板单元作为子层单元,与上述界面单元结合构成的层合板三维有限元模型,通过界面单元刚度的连续衰减模拟分层损伤累积过程。有限厚度的八结点组合界面单元每个结点有5个自由度,能考虑子层结点平动和转动对层间损伤的作用。通过对双悬臂梁(DCB)和末端缺口弯曲(ENF)试验的计算模拟表明,新型组合界面单元和有限元模型能很好地模拟复合材料层合板的分层损伤过程,对不同的网格划分有很好的适应性。

A New Interfacial Element and Finite Element Model for Composite Laminates

A novel interfacial element consisting of eight rigid elements and a zero thickness cohesive element is introduced. The type of elements are of finite thickness and are used together with shell elements to constitute a three dimensional model of composite laminates. Each node of the element possesses five degrees of freedom in common with the adjacent quadrilateral shell elements. Therefore no additional degrees of freedom are required in the finite element model of the laminate except those of the shell elements. The translational and rotational movements of the shell element nodes contribute to the deformation of cohesive elements. The interfacial damage accumulation and final delamination are taken into account by the progressive stiffness degradation of the cohesive elements. The crack growth in double cantilever beam (DCB) and end notch flexure (ENF) specimens are simulated with the proposed elements and corresponding finite element models. The simulation results agree pretty well with the experimental data and those in the literature. In addition, it is shown that the interfacial element can adapt to various mesh shapes.