The natural frequencies of AISI 316 stainless steel and analytical simulation of a Lamb wave excited by a point source

Abstract

Monitoring and analysis of acoustic emissions (AEs) generated by material defects is important during nondestructive testing. Here, we characterize the AEs generated during tensile deformation of AISI type 316 stainless steel (SS). The active frequencies of this SS, spanning the 100–200 kHz range, were determined via tensile testing. Fast Fourier Transform (FFT) analysis revealed that the AEs featured four frequency components representative of all signals observed during the strain-hardening stage. For completeness, the propagation of the AE wave, a Lamb wave generated by the point source, was simulated (using the determined frequency components) in a two-dimensional 2 × 80 mm SS plate. The displacement fields that triggered AE of a Lamb wave from a point source were derived by solving the Navier-Lamé equation. This analytical modeling of AE is useful for characterizing emission generated by defects.