Simulation of AE Generation Behavior in 2-Dimensional Polycrystals by Using the Body Force Method

Abstract

AE (Acoustic Emission) generation behavior during microfracture process of 2-dimensional alumina polycrystals is simulated along with its characteristic parameters, by assuming that a microfracture corresponds to an AE event. The microfracture process is simulated by using the body force method. Various AE generation behaviors are predicted as a function of the grain boundary toughness (Kcb), the grain size and the distribution state of residual stresses due to crystalline anisotropy. The predicted AE events have a tendency to occur at higher stress with increasing K cb and with decreasing grain size. By the fracture-mechanical calculation of the crack opening volume, the relative variation of AE amplitude is also simulated. The actual AE measurements are carried out in vacuum for two kinds of alumina with different grain size, and compared with the simulated results. The cumulative AE event curve for 11.5 μm grain size shows good agreement with the simulation when the K cb is 0.35 times the grain toughness (K cg ), and that for 28.2μm shows good agreement with the simulation at K cb =0.45K cg . The results of AE location for both the simulation and the measurement show the similar characteristics of the scattered distribution over the stressed fields.