Collaborative Research: Damage in Soft Solids: Elasticity vs Fracture

这一建议的研究目标是直接根据弹性体的弹性行为、断裂行为和可引发损伤的缺陷的性质来建立对弹性体中损伤的起始和扩展的基本的定量理解。第二个目标是利用这一理解来探索和确定损害可能导致失败的制度，以及在哪些制度下损害可被用作有益的机制。这将通过实验/理论相结合的方法来实现。在实验上，将利用最先进的光学设备在广泛的系统变化条件下原位监测损伤的空间和时间演变。从理论上讲，最近用于分析含有一般类型缺陷的有限变形固体的新的细观力学技术将被用来构建一个断裂力学框架，该框架能够在一般载荷条件下确定非线性弹性固体中的损伤起始和扩展。软固体(弹性体、凝胶和生物组织等能够经历大的可逆变形的材料)力学的一个关键方面是损伤的开始和传播，人们对此知之甚少。该项目将提供前所未有的现场实验数据和对弹性体中损伤起始和损伤扩展过程的精确定量洞察。它还将首次提供易于处理的分析技术，用于研究受任意有限变形的非线性固体中具有真实几何形状的缺陷通过断裂而不可逆的增长。在应用层面，这项工作将提出几何、材料特性和加载条件方面的量化依据，以确定何时损伤导致失效以及何时(以及如何)利用损伤来发挥优势。研究成果将被纳入UIUC和德克萨斯大学奥斯汀分校的研究生课程，研究人员将继续参与指导和外联活动。

The research objective of this proposal is to develop fundamental quantitative understanding of the initiation and propagation of damage in elastomers directly in terms of their elastic behavior, their fracture behavior, and the properties of the defects at which damage can initiate. A second objective is to make use of this understanding to explore and identify regimes where damage may lead to failure and where, on the other hand, it may be utilized as a beneficial mechanism. This will be accomplished by means of a combined experimental/theoretical approach. Experimentally, use will be made of state-of-the-art optical equipment to monitor in-situ the spatial and temporal evolution of damage under a wide range of systematically varied conditions. Theoretically, recent innovative micromechanics techniques for the analysis of finitely-deformable solids containing general classes of defects will be utilized as the basis to construct a fracture mechanics framework with the capability to determine damage initiation and propagation in nonlinear elastic solids under general loading conditions. A key aspect of the mechanics of soft solids (materials such as elastomers, gels, and biological tissues that are able to undergo large reversible deformations) that is poorly understood, is that of the initiation and propagation of damage. This project will provide unprecedented in-situ experimental data and precise quantitative insight into the processes of damage initiation and damage propagation in elastomers. It will also make available, for the first time, tractable analytical techniques to study the irreversible growth via fracture of defects with realistic geometries in nonlinear solids subjected to arbitrary finite deformations. At the applications level, this work will put forward a quantitative basis in terms of geometry, material properties, and conditions of loading to determine when damage leads to failure and when (and how) it may be used to an advantage. Research results will be integrated into the graduate curricula at UIUC and UT Austin, and the researchers will continue their participation in mentoring and outreach activities.