The main aim of this work is to track the evolution of the stiffness tetrad during large plastic strain. Therefore, the framework of a general finite plasticity theory is developed. Some special cases are examined, and the case of a material plasticity theory is considered more closely. Its main feature is that the elasticity law changes during plastic deformations, for which we develop an approach. As sample materials, we use three types of fiber-reinforced composites. For numerical experiments and verification of the model’s predictions, finite element simulations of representative volume elements for uni-, bi- and tri-directional reinforced materials with periodic boundary conditions are used. From these, we extract the stiffness tetrads before and after large deformations of the material. We quantify the change of the stiffness tetrads due to the fiber reorientation. Finally, we propose an analytical evolution with three parameters that account reasonably well for the evolution of the stiffness tetrad.

这项工作的主要目的是跟踪大塑性应变期间刚度四度的演变。因此，开发了通用有限可塑性理论的框架。研究了一些特殊情况，并更仔细地考虑了材料可塑性理论的情况。其主要特征是弹性定律在塑性变形过程中会发生变化，为此我们开发了一种方法。作为样本材料，我们使用三种类型的纤维增强复合材料。为了进行数值实验和模型预测的验证，使用了具有周期性边界条件的单向，双向和三向增强材料的代表性体积元的有限元模拟。从这些中，我们提取出材料大变形前后的刚度四度。我们量化由于纤维重新定向而引起的刚度四分之一的变化。最后，我们提出了具有三个参数的解析演化，这些解析合理地说明了刚度四度的演化。