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.
