FEM evaluation of asymmetrical four-point bending test of S[lc]iC/S[lc]iC composite joints

Abstract

Reliable methods for joining ceramics, for use at elevated temperatures, are enabling technologies for the successful utilization of ceramic components. In this study, the stress distribution of a SiC/SiC composite specimen containing a butt joint consisting of reaction-formed silicon carbide tested by the asymmetrical four-point bending test was precisely analyzed by the finite element method as a means of evaluating the applicability of analytical results. In the case without the effect of the thermal residual stresses, the shear stress distribution at the interface between the base and the joint almost agreed with the analytical theory. For the case with the residual stress, however, the shear stress near the surface was very large and the possibility of an initial crack induced by the residual stress was considered. Moreover, a study of the effect of joint thickness on the residual shear stress indicated that the thickness should be greater than 100 micrometers to prevent specimen deformation.