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

该项目致力于纤维增强聚合物系统的多尺度均匀化（平均化）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。我们的目标是开发通用的和计算效率高的本构模型，能够处理耦合弹粘塑性行为和微观结构的影响-及其演变-在两个不同的长度尺度。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大类的聚合物，金属，生物和地质材料系统，并将借给自己的本构子程序与标准的有限元方法包使用的数值实现。一旦完全开发，它们将取代目前基于线性弹性分析的模型，需要在工业应用中使用大的安全系数。该项目包括两个国际合作项目，一个是与Pierre Suquet（法国国家科学研究中心，马赛）合作，另一个是与Javier Llorca（墨西哥环境与发展研究所，马德里）合作，内容是拟议工作的补充方面。他们将允许参与该项目的学生通过参与多国，多实验室合作项目获得宝贵的国际经验。主要研究者将教授一门关于均匀化方法的课程，并正在撰写一本基于这门课程的书，旨在使非线性均匀化的最新进展能够为更多的读者所用。长纤维增强聚合物的建模和性能的改进应导致航空航天和其他行业的显着节能，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能，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.