This project is aimed at contributing to the development of a mechanics of modern engineered material in the following three areas: (i) interfacial fracture mechanics, (ii) failure modes in thin films and coatings, and (iii) nonlinear composite theory with emphasis on reinforcement of ductile materials against plastic flow and creep. A wide variety of techniques are being tried to improve bonding between dissimilar materials with applications to composite materials, layered electronic packages, and protective coatings. Research is proposed to study the role of plasticity in increasing mixed mode toughness of interfaces and thin ductile adhesive layers. The initiation of through-cracks and interface debonding from small crack-like flaws in thin films and coatings bonded to substrates will be analyzed. Buckling-driven decohesion, which is the primary mode of failure for thin films and coatings under residual compression, will also be studied. Particulate reinforcement of ductile materials has emerged as an important strategy in the development of new structural materials with high specific stiffness or high temperature creep resistance. The goal of our work is to provide a mechanics for predicting the effect of particle shape, volume fraction and distribution on the overall plastic or creep behavior of the reinforced material.
