Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : December 15, 2016 - December 16, 2016
Structural materials (cast iron etc.) undergoing brittle failure produce large number of acoustic emission (AE) events with varying amplitudes. A common and useful method of describing the amplitude distribution of AE signals is by explaining their b-values (slope of the log-linear frequency magnitude distribution of AE events). Conventionally, the b-value of AB is computed by using the methods adopted in seismology since many similarities exist between AE and seismic waves. The b-value is usually obtained either from the cumulative frequency distribution or the discrete frequency distribution of earthquake magnitudes and the same principles hold good for the AE data also. Therefore, b-value characterized by the Gutenberg and Richter’s relations have been investigated according to the Aki’s modification for AE events due to material cracks or crack damages of structural materials. We applied Aki’s proposed Maximum likelihood method for calculating b-values from AE maximum amplitude distribution for acquired AE events during the crack damage experiments in tensile loading to ductile iron (pearlite). The calculation shows good evidence about crack initiation, propagation and damage phenomena as well comparing with microstructural video data.
