Two different approaches are presented for the prediction of the microbuckling of various types of viscoelastic composites under compression. In the first one, an incremental procedure in time is employed to establish, in conjunction with the Laplace’s transform and its inversion, a determinant whose first complex root indicates the occurrence of the failure stress and strain of the composite (with no imperfections) at the critical time. In the second approach, the viscoelastic composite is assumed to possess, due to faulty manufacturing, imperfections. A perturbation expansion of the field in terms of a small parameter establishes a series of problems of various order. It is shown that the solutions of the zero and first-order problems yield, in conjunction with the Laplace’s transform and its inversion, the imperfection growth with applied loading, which asymptotically approaches the bifurcation buckling stress of the viscoelastic composite. In both approaches a repeated application of the high-fidelity generalized method of cells (HFGMC) micromechanics is employed to obtain the solutions. The offered two analyses are verified and applied on bi-layered, continuous and short fiber viscoelastic composites, as well as on viscoelastic woven composites and lattice blocks. The latter two applications necessitate the employment of multiscale HFGMC micromechanical analyses since the yarns in the weaves and the elements of the lattices are themselves unidirectional viscoelastic composites.

提出了两种不同的方法来预测各种类型的粘弹性复合材料在压缩下的微屈曲。在第一个中，采用时间增量程序，结合拉普拉斯变换及其反演，建立一个行列式，其第一个复数根表示复合材料（无缺陷）在关键时刻。在第二种方法中，假设粘弹性复合材料由于制造缺陷而具有缺陷。就一个小参数而言，场的微扰扩展建立了一系列不同阶的问题。结果表明，零阶和一阶问题的解结合拉普拉斯变换及其反演产生，施加载荷时缺陷的增长，渐近接近粘弹性复合材料的分叉屈曲应力。在这两种方法中，重复应用细胞的高保真广义方法 (HFGMC) 微力学来获得解决方案。所提供的两种分析已在双层、连续和短纤维粘弹性复合材料以及粘弹性编织复合材料和格子块上得到验证和应用。后两种应用需要使用多尺度 HFGMC 微机械分析，因为编织中的纱线和格子的元素本身就是单向粘弹性复合材料。在这两种方法中，重复应用细胞的高保真广义方法 (HFGMC) 微力学来获得解决方案。所提供的两种分析已在双层、连续和短纤维粘弹性复合材料以及粘弹性编织复合材料和格子块上得到验证和应用。后两种应用需要使用多尺度 HFGMC 微机械分析，因为编织中的纱线和格子的元素本身就是单向粘弹性复合材料。在这两种方法中，重复应用细胞的高保真广义方法 (HFGMC) 微力学来获得解决方案。所提供的两种分析已在双层、连续和短纤维粘弹性复合材料以及粘弹性编织复合材料和格子块上得到验证和应用。后两种应用需要使用多尺度 HFGMC 微机械分析，因为编织中的纱线和格子的元素本身就是单向粘弹性复合材料。