Effects of Microstructural Variability on the Mechanical Properties of Ceramic Matrix Composites

This paper presents a method to model variability in architectural parameters and predict the resultant uncertainty in the mechanical properties of a SiC/SiC ceramic matrix composite system. Using micrographs of three specimens, the relative importance of these architectural parameters on the mechanical properties is also identified. Both finite element analysis and an analytical method (Selective Averaging Method) are used. Response surfaces are used to relate the high-fidelity finite element analysis and the low-fidelity Selective Averaging Method. Various response surfaces are evaluated and used to obtain a large number of results in a relatively short amount of time (compared to using finite element analysis alone). The results reveal that modeling the random variation in all architectural parameters in a way that mimics the actual variation in the composite is important in order to obtain a satisfactory representation of the variability in the stiffness properties of the composite. M.B. Goldsmith, Graduate Student ([email protected]) B.V. Sankar, Ebaugh Professor ([email protected]) R.T. Haftka, Distinguished Professor ([email protected]) Department of Mechanical and Aerospace Engineering P.O. Box 116250, University of Florida, Gainesville, FL 32611, USA R.K. Goldberg, Aerospace Engineer ([email protected]) NASA Glenn Research Center, Mechanics and Life Prediction Branch, 21000 Brookpark Rd., Cleveland, OH 44135, USA Effects of Microstructural Variability on the Mechanical Properties of Ceramic Matrix Composites M. B. GOLDSMITH, B. V. SANKAR, R. T. HAFTKA AND R. K. GOLDBERG