INITIATION OF MATRIX CRACKING IN WOVEN CERAMIC MATRIX COMPOSITES

摘要

In this study, we employ detailed 3D finite element models of complex plain and satin weave ceramic matrix composites to address the problem of initiation of matrix cracking. Fundamental 3D elasticity boundary value problems addressing the response of these materials under the combined effects of remote biaxial tension and pure shear loads coupled with residual thermal stresses are utilized as needed to characterize the matrix micro-stresses in the vicinity of large-scale macroscopic voids. The combined stress fields are then used to determine the effects of remotely applied in-plane loads and thermal temperature gradients on the initiation of matrix cracking in the region of high stress concentrations. Selective comparison of model results with available experimental data are discussed. Extensive parametric studies have been carried out and robust failure loci predictive of the "first" matrix cracking events have been developed. The availability of such failure envelopes for woven CMCs offers for the first time a design tool for the use of such advanced systems in engineering applications.