Lamb wave dispersion compensation in piezoelectric wafer active sensor phased-array applications

Lamb-wave testing for structural health monitoring is complicated by the dispersion nature of the wave modes. The dispersion effect will result in a propagated wave with longer time duration, deformed envelop shape as compared to its excitation counterpart, and hard to be interpreted. This paper first reviews the dispersion compensation and removal algorithms. Second, it compares these two methods by applying them to two widely used low-frequency Lamb wave modes: S0 and A0. Numerical simulations are compared in parallel with experimental results. Finally, the dispersion compensation algorithm is applied to 1-D PWAS phased array and demonstrated to improve the phase array's spatial resolution.