Science of Fracture.

This research program is intended to explore and develop commonalities in fracture theory as applied to wide classes of differing materials at different scales - from the atomic to the continuum. Primary attention is focused upon analytical and experimental methods needed to analyze underlying and potentially common basic mechanisms controlling the fracture process, e.g. two and three dimensional stress singularities, effect of environment, etc. and to examine structure-property relationships, including the effect of the fabrication process upon the preparation of specimens made from standardized model materials representative of polymers and metals. Secondary emphasis is focused upon numerical analysis methods needed at various scale levels, atomic to continuum, and instrumentation capability peculiarly suited to or needed for fracture studies. In later stages of the program, increasing attention will be devoted to technology transfer and engineering applications of the basic research. Major results during the first year include 1 the development of a test for measuring Mode II fracture toughness, and 2 quantifying the effect of geometry in an embedded fiber or rod and the location of initial interfacial debonding from the matrix upon resulting adhesive fracture under load. Author