Paper number 1185

PROBABILISTIC CERAMIC MATRIX COMPOSITE BEHAVIOR

Pappu L.N. Murthy¹ and Subodh K. Mital²

1Structures Division, John H. Glenn Research Center
National Aeronautics and Space Administration
Cleveland, Ohio 44135, U.S.A.
2Department of Mechanical, Industrial and Manufacturing Engineering
The University of Toledo, Toledo, Ohio 43606, U.S.A.

Summary

In this paper an overview of in-house activities pertaining to Ceramic Matrix Composite (CMC) modeling and probabilistic CMC material behavior simulation are presented. The approach consists of a synergistic combination of two in-house developed methodologies. The first methodology is concerned with modeling of CMC behavior using micromechanics and macromechanics. The second one consists of a FPI (Fast Probability Integration) technique that takes into account the uncertainties occurring on various scales in a composite and computes the cumulative probabilistic distribution functions of composite global behavior. The methodology is applied to two CMC material systems including a woven CMC system. Results are presented in terms of cumulative probabilistic distribution functions of composite stiffnesses, thermal properties and strengths. In addition to cumulative distribution functions (CDFs) of response, the FPI technique provides additional information regarding the sensitivity of the response with respect to the primitive variables. The sensitivity information is very useful from the design point of view and can be used to rank the various input variables in the order of their importance in controlling the output response and scatter.

Keywords

micromechanics, macromechanics, fiber substructuring, unit cell, cumulative distribution function, probability density function, and sensitivities.