Quantitative Analysis of the Hsu-Nielsen Source through Advanced Measurement and Simulation Techniques

This paper presents the results from conducting a series of experiments with a Hsu-Nielsen Source, accompanied by corresponding numerical simulations on a solid block. The aim being to illustrate a Finite Element Analysis (FEA) approach for simulating Acoustic Emission (AE) wave propagation in a Hsu-Nielsen Source, by employing virtual sensors to enhance existing AE research methodologies. The objective was to examine and establish the actual unload rate derived from Pencil Lead Breaks (PLBs) by comparing results from simulations and experimental trials. These experiments and simulations were conducted using a solid cylindrical steel block, capturing the propagating Acoustic AE waves from both sources over a two-second span. When comparing the experimental data with the simulation results, it is evident that replicating the structure of an impulsive AE source is feasible for brief durations. Furthermore, both the experimental and simulated signals on the steel cylinder displayed comparable patterns in the initial 25-30 µs. The methodology presented in this study demonstrates the effectiveness of Finite Element Analysis (FEA) in precisely identifying the specific modes present in AE wave propagation, including the actual unload rates affecting the AE signals recorded.