Research of relationship between Lamb wave velocity and static stress of metal plate

On the assumption that isotropic metal solid becomes anisotropic property in the state of stress, based on the theory of the nonlinear acoustoelasticity, the equivalent second order elastic constants is calculated for metal plate with static stress. For the case of thin metal plate with stress, the two kinds of dispersion equation for Lamb weave parallel or vertical to direction of static stress are derived. Using the equations, the relationship between Lamb wave velocity and static stress in metal plate is discussed.