MODELING OF MATRIX FAILURE IN CERAMIC-MATRIX COMPOSITES

This paper investigates failure criteria used in modeling matrix failu re in unidirectional and cross-ply laminates of ceramic matrix composi tes. In particular, the critical matrix strain energy (CMSE) criterion , as recently introduced by the authors, is examined in detail. In pri nciple, a failure criterion, such as CMSE, which does not require many empirical constants, is desired. This CMSE approach provides a simple closed-form estimate for the matrix crack density in ceramic matrix c omposites when subjected to monotonic tensile loading. The proposed cr iterion can be easily extended to more complex loading conditions (for example, fatigue) and laminate geometries. Other matrix failure crite ria, available in the literature, are also discussed. The CMSE criteri on does an adequate job of estimating the evolution of matrix damage i n both unidirectional and cross-ply laminates.