Modeling and computation of time-continuous evolution of microstructures

该项目旨在对塑料材料中微观结构的形成和随后的演变有一个基本的了解，并为有效的计算开发全面而有效的工具。变分公式结合适当的松弛概念和有效的数值算法是我们工作的一个关键组成部分，基于我们第一阶段的结果，我们提出的描述有限塑性层合板微观结构的模型将被推广到几个方向，并通过实验验证。现有的模型扩展到高阶层压板将进行和新的方法来考虑更一般的，复杂的微结构几何形状将得到解决。将研究几种主动滑移系统在潜在硬化相互作用方面的影响。此外，晶格位错的影响，以构成层压细胞壁将被调查关于其本质上的影响层压形成和层压取向的演变。为了验证扩展模型的有效性，我们将对单晶体进行具体的变形实验。晶体将以这样一种方式取向，即正好有两个滑移系是活跃的，这将是与理论结果进行比较的最有效的方式。此外，还将进行循环荷载试验，以便更密切地研究理论预测的某些安定现象。

This project aims to gain a fundamental understanding of the formation and subsequent evolution of microstructures in plastic materials, and to develop comprehensive and efficient tools for their effective computation. The variational formulation in combination with appropriate relaxation concepts and efficient numerical algorithms is a key ingredient of our work.Based on our results from the first period, our proposed model for the description of laminate microstructures in finite plasticity shall be generalized into several directions and validated experimentally. An extension of the existing model to higher-order laminates will be carried out and novel approaches to account for more general, complex microstructure geometries will be addressed. The influence of several active slip systems in terms of latent-hardening interactions will be investigated. Also, the influence of lattice dislocations to constitute the laminate cell walls will be investigated with respect to their essential influence on both laminate formation and the evolution of the laminate orientation. A generalization to account for thermomechanical coupling is envisaged.Specific deformation experiments on single crystals will be performed in order to validate the extended models. The crystals will be oriented in such a way, that exactly two slip systems will be active, which will be most efficient for comparison with the theoretical results. Moreover, cyclic loading test will be performed in order to investigate more closely certain shake-down phenomena predicted by theory.