Nonlinear acoustic applications for material characterization: A review

The nonlinear acoustic applications for material characterization are revie wed. The general theoretical analysis of the effects of nonlinearity, dissi pation, dispersion, and diffraction on intense acoustic-wave propagation is given. Acoustic nonlinear parameters and their determination methods are i ntroduced. The investigations of nonlinear acoustic applications for solid material evaluation are discussed for different levels of disruption, from asymmetry of lattice structure and dislocation in crystals to disbonds and cracks in engineering materials. The experimental methods involved in these investigations are also considered. The techniques used for nonlinear acou stic imaging are divided into two categories, concerned with resolution imp rovement by using higher harmonics, and nonlinear parametric imaging. The n onlinear acoustic applications in biomedical imaging, acoustic microscopy, and nonlinear nondestructive evaluation are presented. Finally, the issues that need further investigations in this area are discussed.