With proposing identical particle and virtual particle hypothesis, the control condition of two-dimensional velocity is derived,and the propagation of linear waves is described at the atomic scale with using interatomic potential functions.Furthermore, the generation mechanism of the second-order nonlinear waves is studied by considering the effects of lattice anharmonicity and dislocation. The study shows that the lattice distortion caused by lattice anharmonicity and dislocation induces high-order virtual particles, which are the key factor in generating the high-order nonlinear waves, and early-stage nonlinearities or micro-damages, e.g., dislocation, lead to the increase of the high-order virtual particles, which induces obvious high-order nonlinear waves. Therefore, the early-stage micro-damages can be identified by detecting the high-order nonlinear waves.
