Theoretical and numerical analysis of acoustic emission guided waves released during crack propagation

Abstract

This article presents a theoretical and numerical analysis of guided wave released during an acoustic emission event using excitation potentials. Theoretical formulation showed that guided wave generated using excitation potentials follows the Rayleigh–Lamb equation. The numerical studies predict the out-of-plane displacement of acoustic emission guided wave on the plate surface at some distance away from the source. Parameter studies were performed to evaluate the effect of (1) pressure and shear potentials acting alone and in combination, (2) plate thickness, (3) source depth, (4) rise time, and (5) propagating distance away from the source. Numerical results showed that peak amplitude of S0 signal increases with increasing plate thickness, whereas the peak amplitude of A0 signal initially decreases and then increases with increasing plate thickness. Regarding the source depth, it was found that peak amplitude of S0 signal decreases and A0 signal increases with increasing source depth. Peak time showed a notable contribution to the low-frequency component of A0 signal. There were large losses in S0 and A0 peak signal amplitude over the propagation distance from 100 to 500 mm.