Simulation of Propagating Acoustic Emission Waves from In-Plane Dipole Source Using Infinite Element to Eliminate Reflected Waves from Sidewalls

Acoustic emission is a phenomenon in which an elastic wave within 20 KHz- 1 MHz range suddenly dissipates from a local area inside the material. In simulation of acoustic emission in small impacts, a problem exists in the reflection of wave from its sidewalls. This point causes problem in the analysis of acoustic emission signals. In order to do away with this problem, using sheets of greater dimensions are suggested. Nevertheless, there are difficulties in doing so; due to higher cost of simulation as well as longer period of time to do the calculations. In this investigation, instead of using large dimension sheets causing high volume of mathematical calculations, infinite elements have been used to simulate side walls of the sheet. Effects of reflected waves from sidewalls in this technique are excluded; hence less amount of time would be needed for calculations. Acoustic emission Simulation took place for two types of sheets: normal type and sheet having infinite elements in its side walls. Collected data from both simulations indicate that using infinite elements cause reflected waves from side walls to be exonerated. Numbers of considered elements were reduced drastically and hence calculation time was reduced accordingly. Also, comparison was made for exclusion of reflected waves from sidewalls of regular sheets with small and large dimensions with infinite elements.