Analysis of apparent fracture toughness of a thick-walled FGM cylinder with two diametrically opposed edge cracks

This study focuses on the analysis of apparent fracture toughness of a thick-walled functionally graded material (FGM) cylinder with two diametrically opposed edge cracks emanating from the inner surface of the cylinder. The crack surfaces and the inner surface of the cylinder are subjected to an internal pressure. The incompatible eigenstrain developed in the cylinder due to non-uniform coefficient of thermal expansion after cooling from sintering temperature is taken into account. Based on a generalized method of evaluating stress-intensity factor developed in our previous study, an approach is presented to evaluate apparent fracture toughness. To demonstrate the approach, some numerical results of apparent fracture toughness are presented for a TiC/Al(2)O(3) FGM cylinder. The effects of material distribution, cylinder wall thickness, application temperature and number of cracks on apparent fracture toughness are investigated in details. It is found that all these factors play an important role in controlling apparent fracture toughness of a thick-walled FGM cylinder.