Fracture Simulation in Sintered Silicon Nitride Based on Probability Distribution of Defects Size and Micro-Crack Propagation Behavier. 1st Report. Monotonic Bending Stength.

Abstract

In this study, a computer simulation taking into account the defects size distribution and the micro-crack propagation behavior was conducted by using virtual bending specimens. The defects size distribution in the virtual specimens was estimated by using a Monte-Calro technique based on a large number of defects diameter (approximately 72 000) measured on the Si3N4 specimen surface. For the cases of the simulation using micro-crack propagation behavior, the estimated bending strength well coincided with the factual bending strength. The scatter of the defect size and the crack propagation rate was estimated separately. Through the evaluation of the effects of scatter in a crack propagation rate, it is reconfirmed that the wide scatter in fracture strength mainly originated from the scatter of defect size.