Nonlinear interaction of Rayleigh waves in isotropic materials: Numerical and experimental investigation.

Surface treatment intensity monitoring is still an open and challenging nondestructive testing problem. For the estimation of residual stress with ultrasonic measurements, local linear and nonlinear elastic constants are needed as input. In this paper, nonlinear elastic-wave interactions (also called wave mixing or scattering) - namely, the generation of secondary ultrasonic waves in a nonlinear medium - are considered as a prospective means for near-surface nonlinear elastic parameter evaluation.