Diagnostics of metal plates with residual stresses and defects by nonlinear scanning laser vibrometry

Abstract

Nonlinear scanning laser vibrometry is used for diagnostics of cylindrical resonators made of poly crystalline aluminum alloy with residual stresses and defects. The diagnostics is performed with flexural Lamb waves. The eigenmode frequency of such a resonator is found to depend on the amplitude of flexural Lamb waves excited in it (the fast dynamics effect), which points to the presence of a nonclassical nonlinear elastic ity in the resonator material. Studying the nonlinear interactions between amplitude modulated flexural Lamb waves in resonators allow the determination of the coordinates of defects and residual strains in them.