The objective of the proposed research is the thorough understanding of fundamental phenomena in dynamic fracture of homogeneous and bimaterial systems subjected to high shearing loads. Recent experimental evidence during shear dominated crack propagation along interfaces, has shown the development of supersonic crack speeds and crack face contact. In addition, theoretical evidence predicts supersonic speeds even in homogeneous materials, under high shear loading, if the homogeneous material exhibits a cohesive type failure response. Here, experimental and numerical analysis will be conducted to scrutinize the physical details of the contact zone and of limiting crack speeds in bimaterial interface and homogeneous material systems. Special emphasis will be placed on the issue of crack face friction and subsequent heating during contact. The educational part of this proposal describes a plan for improvement of teaching practices in current courses and enhanced undergraduate laboratories, including animated classroom presentations as well as physical demonstrations of counter-intuitive dynamical systems.
