音弾性法によるセラミックスのき裂損傷評価

抄録

It is known that many micro-cracks would be introduced by surface grinding in process of machining of ceramics. The initial cracks appear as series of semicircular surface cracks beneath the grinding groove. Under applied loading some of the cracks coalesce and extend stably to an elongated semi-elliptical surface crack configuration at failure. So, it is needed to predict the existence of the elongated crack before failure. Acoustoelasticity is a non-destructive method not only to detect flaw but also to estimate quantitatively the change of microstructure. In this paper, by examining the dependency of the crack length on the third order elastic constants in two kind ceramics of glass ceramics and partially stabilized zirconia the possibility to nondestructive inspection in ceramics was evaluated. As a result, there was a significant correlation between the crack size and the third order elastic constants, and the application of acoustoelasticity to the estimation of crack damage could be quite possible.