Abstract

Nonlinear Acoustic Detection of Cracks

A.Stromkov, V.V.Chernov, I.N.Didenkulov, N.V.Kurochkin (Institute of Applied Physics RAS, Nizhny Novgorod, Russia)

e-mail: strom@appl.sci-nnov.ru

It has been relatively recently known that cracks have high nonlinear elasticity. It causes different nonlinear acoustic responses such as higher harmonics generation or nonlinear modulation of an ultrasound wave passing through or reflected from a crack by low frequency vibrations of a testing object. These effects are used for the development of methods of nonlinear acoustic nondestructive evaluation. Simple technique can be used for detection of damaged objects. However such technique cannot give information on crack location. Advanced methods allow one to measure crack position. In this paper methods of crack detection and location are considered. They are based on modulation of high-frequency acoustic wave passed through the crack by low-frequency vibrations of testing object. Experimental examples demonstrate that the nonlinear acoustic techniques can be effective for nondestructive testing of different objects. This work was supported by the ISTC (1369) and RFBR (01-02-16938).

Section : 3