"Time Reversal, Elasticity and Nonlinearity"

Dr.  Timothy J. Ulrich II

Abstract

Time Reversal (TR) is a technique used in wave propagation to redirect wave energy “backwards” in time to focus, both in time and space, upon the source of the wave field.  Performing TR in elastic media, i.e., 3-dimensional solids, complicates the physics of the process due to the presence of a variety of wave motion possibilities (e.g., compressional, shear, and surface waves).  Further adding to the complexity is the phenomenon of nonlinear elasticity often, though not exclusively, attributed to fractures in the solid.  This talk will present the fundamentals of TR, elasticity and nonlinearity.  Current and future applications of performing TR using linear and nonlinear elastic wave propagation will also be discussed with the support of recent experimental and modeling studies performed at the Los Alamos National Laboratory.