复合材料夹芯结构褶皱增强理论和有限元方法

Enhanced theory and finite element method for wrinkling analysis of composite sandwich structure

  • 摘要: 复合材料软核夹芯结构承受面内载荷,面板可能出现褶皱。一旦面板出现褶皱,夹芯结构将失去承载能力。因此,需要发展准确的理论模型预测软核夹芯结构褶皱行为。夹芯结构褶皱是典型三维(3D)问题,鲜有高阶模型能准确预测此类问题。为此,提出考虑局部形变和三维效应的增强型高阶模型。基于此理论,推导了梁单元公式,并分析了不同边界条件复合材料夹芯结构的起皱行为。通过与准三维弹性解和三维有限元解对比,提出方法的准确性得到验证。为了提高夹芯结构抗起皱能力,尝试使用复合材料面板代替金属面板。数值分析结果表明,发展的增强型高阶模型可以准确分析复合材料夹芯结构褶皱行为,并且使用复合材料面板可有效提升夹芯结构抗起皱能力。

     

    Abstract: Panels wrinkling behaviors may occur when composite soft-core sandwich structures subjected to coplanar compression loads. Once the panels wrinkling appears, the sandwich structures will lose its load-bearing capacity. Therefore, it is necessary to develop an accurate model to predict the wrinkling behaviors of soft-core sandwich structures. Sandwich structure wrinkling is a typical three-dimensional (3D) problem, and few high-order models can accurately predict such issues. Therefore, this paper proposed an enhanced higher-order model including the local deformation and the 3D effects. Based on the proposed theory, the beam element formulation was derived, and the wrinkling behaviors of sandwich structures with different boundary conditions were analyzed. By comparing with the quasi-3D elasticity solution and the 3D finite element results, accuracy of the proposed method has been verified. In order to improve the capability of sandwich structures resisting the wrinkling deformation, this work attempted to use composite face sheets instead of metal panel in the sandwich structure. Numerical results show that the developed enhanced high-order model can accurately predict the wrinkling behaviors of the composite sandwich structures, and the use of composite panels can effectively resist the wrinkling behaviors of sandwich structures.

     

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