Nonlinear acoustics of solids: History and modern trends

Abstract

The author had the pleasure to be involved in the pioneering experiments on the nonlinear acoustic wave propagation in crystals and metals (1960). It was found that even for small wave amplitudes acoustic harmonics generation took place for longitudinal waves. The results obtained were interpreted from the point of view of Hooke’s law nonlinearity due to nonparabolic interaction potential taking into account accumulation effects in nondispersive media. Besides that, transversal acoustic waves under some external effects like pressure, heating, etc., also demonstrated nonlinear behavior despite that it was forbidden in a framework of crystal lattice theory. It was accounted for by the development of structural disturbations in a material and seemed to be the first attempt to demonstrate the importance of acoustic nonlinear nondestructive testing of different materials. It was shown later that some construction materials and rocks have much higher nonlinear parameter values than those for crystals and metals. The paper will also present an historical review of recent developments in other areas of nonlinear acoustics in solids: measurements of nonlinear acoustic parameters, surface acoustic waves nonlinearity, ‘‘clapping’’ nonlinearity, defective solids and rocks, etc.