George E. Duvall Shock Compression Science Award Talk: Mesomechanical Modeling of Fracture

This paper reviews the efforts of the author and his colleagues over the past four decades to develop mesomechanical models of material failure. In the early 1970s a procedure known as NAG/FRAG (Nucleation and Growth to Fragmentation) methodology was introduced by a group at SRI International. Experiments are performed in which the evolution of microstructural damage is is measured pre and posttest as a function of stress, time-at-stress, temperature, and other environmental parameters. Damage nucleation and growth functions are deduced via iterative computational simulations. We review the history over the past half-century for applications of growing complexity, and conclude with a discussion of a current challenging problem, that of designing improved glass and ceramic armors.