Application of counterpropagating nonlinear waves to material characterization

Summary.

Ultrasonic nondestructive evaluation (NDE) of physical properties of nonlinear inhomogeneous materials is possible by extraction of extended information from the ultrasonic wave propagation measurement data. The nonlinear elastic material with weak inhomogeneity is considered. Two counterpropagating waves are excited simultaneously on the opposite parallel boundaries of the material. The analytical description of propagation, reflection and interaction of these two waves is presented. The resulting oscillations at the boundaries of the material are analysed, and the dependence of the oscillation parameters on the material properties is clarified. The NDE problem is also solved using the nonlinear effects in the boundary oscillation. The pertinent numerical examples are discussed.