Acoustic emission-stress intensity factor relations for tensile deformation of notched specimens of AISI type 304 stainless steel

Abstract

Interrelation between acoustic emission (AE) and stress intensity factor (K) has been examined using data generated during deformation of a series of single edge-notched tensile specimens. The experiments were carried out on nuclear and commercial grade AISI type 304 stainless steel sheet specimens of different thickness. Analyses of AE total counts (N) versus K in log-log scale indicate Nto bear the popular relationship with K as N=AK^m where A and m are constants; but the magnitudes of A and m are different at low and high K regimes. Both the steels indicate higher values of m up to macroyielding than those obtained from analysis of AE data between macroyielding and the stress corresponding to K_max values in the experiments. The magnitudes of m were found to be higher for the commercial grade steel than that for the nuclear grades one. In addition to the new observation of two regimes for the N=AK^m relation, it was also noted that the value of m is dependent on the thickness. The variation of N with specimen thickness in the two steels appears to provide further evidence of acoustic emission from inclusion decohesion.