Computation and simulation of reliability parameters and their variations in heterogeneous materials

Two numerical methods for reliability assessment for composite microstructu res under arbitrary loading are presented: a Monte Carlo (MC) technique tha t assigns discrete failure probabilities from local stresses and empirical failure probabilities, and a parametric probability product (PP) method whe re the joint probability of survival is from a product over a set of hetero geneous finite elements. The two methods are verified for known cases and t hen applied to random composite microstructures that are not amenable to di rect analysis. While the MC method is computationally more expensive and le ss accurate than the PP method, it produces a distribution of failure predi ctions. The distribution places confidence intervals on survival probabilit ies or estimates for the number of physical experiments required to predict Weibull parameters. A composite microstructure does not have a failure dis tribution of the same form as its homogeneous composite parts, but its form is readily understood. (C) 2000 Acra Metallurgica inc. Published by Elsevi er Science Ltd. All rights reserved.