Simulation of local material properties based on moving-window GMC

When analyzing the behavior of composite materials under various loading co nditions, the assumption is generally made that the behavior due to randomn ess in the material can be represented by a homogenized, or effective, set of material properties. This assumption may be valid when considering displ acement, average strain, or even average stress of structures much larger t han the inclusion size. The approach is less valid, however, when consideri ng either behavior of structures of size at the scale of the inclusions or local stress of structures in general. In this paper, Monte Carlo simulatio n is used to assess the effects of microstructural. randomness on the local stress response of composite materials. In order to achieve these stochast ic simulations, the mean, variance and spectral density functions describin g the randomly varying elastic properties are required as input. These are obtained here by using a technique known as moving-window generalized metho d of cells (moving-window GMC). This method characterizes a digitized compo site material microstructure by developing fields of local effective materi al properties. Once these fields are generated, it is straightforward to ob tain estimates of the associated probabilistic parameters required for simu lation. Based on the simulated property fields, a series of local stress fi elds, associated with the random material sample under uniaxial tension, is calculated using finite element analysis. An estimation of the variability in the local stress response for the given random composite is obtained fr om consideration of these simulations. (C) 2001 Elsevier Science Ltd. All r ights reserved.