Fiber-Reinforced Polymeric Material Systems: A Multi-Scale, Elasto-Viscoplastic Homogenization Approach

该项目涉及纤维增强聚合物系统的多尺度均质（平均）技术，包括长纤维增强聚合物和具有圆柱形结构的热塑性弹性体。目标是开发通用且计算效率高的本构模型，能够处理两种不同长度尺度下的耦合弹粘塑性行为和微观结构的影响及其演变。还将研究宏观和微观不稳定性的可能发展。在这项工作中开发的技术将广泛应用于聚合物、金属、生物和地质材料系统的大类别，并将有助于在本构子程序中与标准有限元方法包一起使用的数值实现。一旦完全开发，它们将取代目前基于线性弹性分析的模型，在工业应用中需要使用大的安全系数。该项目包括两个国际合作，一个是与Pierre Suquet（法国国家科学研究中心，马赛），另一个是与Javier Llorca （IMDEA，马德里），在拟议工作的补充方面。他们将使参与该项目的学生通过参与多国、多实验室的合作项目获得宝贵的国际经验。首席研究员将教授一门关于均质化方法的课程，并正在根据这门课程编写一本书，旨在将非线性均质化的最新进展介绍给更多的读者。长纤维增强聚合物的建模和性能的改进应该会导致航空航天和其他工业的显著节能，而更好地了解热塑性弹性体是非常可取的，因为它们的可回收性，以及随之而来的对环境的积极影响。

This project addresses multi-scale homogenization (averaging) techniques for fiber-reinforced polymer systems, including long-fiber reinforced polymers, and thermoplastic elastomers with cylindrical structures. The goal is to develop general and computationally efficient constitutive models that are capable of handling coupled elasto-visco-plastic behavior and the effect of microstructure--and its evolution--at two different length scales. The possible development of macroscopic and microscopic instabilities will also be investigated. The techniques to be developed in this work will be of broad application to large classes of polymeric, metallic, biological and geological material systems, and will lend themselves to numerical implementation in constitutive subroutines for use with standard finite element method packages. Once fully developed, they will replace current models based on linear-elastic analyses, requiring the use of large safety factors in industrial applications. This project includes two international collaborations, one with Pierre Suquet (CNRS, Marseilles) and the other with Javier Llorca (IMDEA, Madrid), on complementary aspects of the proposed work. They will allow the students involved in this project to acquire valuable international experience through participation in multi-country, multi-laboratory collaborative projects. The principal investigator will teach a course on Homogenization Methods, and is also writing a book that is based on this course, which aims to make the recent progress in nonlinear homogenization available to a larger audience. Improvements in the modeling and performance of long-fiber-reinforced polymers should lead to significant energy savings in the aerospace and other industries, while better understanding of thermoplastic elastomers is highly desirable because of their recyclable properties, and consequent positive implications for the environment.