ASSESSMENT OF A MICROMECHANICS-BASED PROGRESSIVE DAMAGE AND CREEP MODEL APPLIED TO CERAMIC MATRIX COMPOSITES WITH HOLES

An assessment of the ceramic matrix composite (CMC) lifing software CMC Life Prediction (CLIP) was carried out on a variety of challenge problems including tensile response of a specimen with multiple holes as well as creep response and residual strength of an open hole specimen. For this evaluation, the 2014 version (S5-1405) of the CLIP software was provided by Structural Analytics Inc. (SAI). Both challenge problems presented in this manuscript utilized S200H SiC/SiNC CMC material system with an eight-harness satin (8HS) woven architecture. Calibration of the model was conducted using tensile data, in both the [0/90] and [±45] orientations, as well as creep data over a range of stresses. Blind predictions were then made for the specimens with features (single or multiple holes) resulting in a multiaxial stress state and compared against experimental data for each of the challenge problems. The capability of CLIP to predict various quantities such as ultimate strength, crack path, and steady state creep strain rate, for example, was assessed. CLIP performed well for the two problems presented. However, important areas for improvement are noted such as deficiencies identified in simulating residual tensile behavior following creep.