NUMERICAL-ANALYSIS ON CHIPPING FRACTURE OF SILICON-NITRIDE

Chipping fracture behaviour of silicon nitride ceramics was examined by both experimentally and numerically. Experimental results showed that both width and hight of the cone crack generated at the edge portion were enlarged comparing to those of the cone crack generated at the center of specimen in the range of 480 +/- 10 m/s impact velocity. Three dimensional numerical analysis exhibited the agreement between calculation and experimental results in the size of the cone crack and in the direction of cone extension using Liaw's elastic fracture model. It is concluded that three dimensional numerical analysis based on Liaw's criteria can show complicated dynamic fracture behavior.