Finite-Strain, Constitutive Models for Semi-Crystalline Polymers

半结晶聚合物的有限应变本构模型

• 批准号: 0654063
• 负责人: Pedro Ponte Castaneda
• 金额: --
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-15 至 2011-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0654063&HistoricalAwards=false
• 关键词: Finite; Strain; Constitutive; Models; Semi

PI proposes to develop finite-strain constitutive models for semi-crystalline polymers, such as polyethylene and polypropylene. These are multi-phase material systems consisting of a "soft" phase that provides elasticity to the system in intimate contact with a "hard" phase that is responsible for plastic deformation at large strains. They exhibit structure on two different length scales, ranging from the nanometer scale, at which the constituent polymer chains order themselves into "lamellar" structures, to the micrometer scale, where either randomly oriented "lamellar grains," or "spherulitic grains" are observed. Because these polymers are among the most commonly used in many applications, including in the packaging, fluid distribution, automotive and toy industries, there is great interest in manipulating their structure to optimize their mechanical response. Improvements in their mechanical properties are expected to have a positive impact on the environment. The methodology to be developed will make use of variational "linear comparison" homogenization techniques, and will account for: (i) the strongly nonlinear response of the constituent phases, (ii) the dual microstructure at the "grain" and "polycrystal" levels, (iii) coupled elasto-viscoplastic constitutive behavior, and (iv) finite deformations. The work will involve close collaborations with the experimental group of Jean-Yves Cavaille at the INSA de Lyon (France). Efforts will be made to recruit a top-level minority graduate student, who will benefit from the PI's on-going international collaborations. The PI is writing a book that aims to make recent progress in nonlinear homogenization---including the present work on polymeric systems---available to a larger audience.

PI提议为半晶聚合物（例如聚乙烯和聚丙烯）开发有限的组合模型。这些是由“软”相组成的多相材料系统，该系统在与“硬”相的紧密接触中为系统提供了弹性，该相位负责在大型菌株下塑性变形。它们在两个不同的长度尺度上表现出结构，范围从纳米尺度，其中组成的聚合物链在该尺度上订购自己为“层层”结构，到千分尺尺度，在其中观察到随机定向的“薄片晶粒”，或者观察到“球形晶粒”。 。由于这些聚合物是许多应用中最常用的聚合物之一，包括包装，流体分布，汽车和玩具行业，因此对操纵其结构以优化其机械响应引起了极大的兴趣。预计其机械性能的改善将对环境产生积极影响。要开发的方法将利用变分的“线性比较”均质化技术，并说明：（i）组成阶段的强烈非线性响应，（ii）“谷物”和“多晶”水平的双重微观结构，（iii）耦合的弹性塑性构成行为和（iv）有限变形。这项工作将涉及与Insa de Lyon（法国）Jean-Yves Cavaille的实验小组的密切合作。将努力招募高级少数族裔研究生，他们将从PI的持续国际合作中受益。 PI正在撰写一本旨在在非线性均质化方面取得最新进展的书 - 包括目前关于聚合系统的工作 - 较大的受众群。