Author(s)

J. Vorel, J. Nˇemeˇcek & M. ˇSejnoha

Abstract

Material modeling plays an irreplaceable role in assessing the practical applicability of any type of material system. A successful approach requires with no doubt a combination of experimental measurements with predictive numerical simulations. While numerical simulations of complex heterogeneous materials often rely on the well established concept of the statistically equivalent periodic unit cell, its formulation for complex material systems, such as carbon–carbon (C/C) composites, is far from trivial, particularly in view of a hardly negligible intrinsic porosity of these material systems. Here reliable information about the actual size, shape and distribution of pores in the composite are provided using X-Ray microtomography combined with two-dimensional images of composite sections. Similarly, difficulties arise when searching for reliable material data of individual constituents. Although usually supplied by the manufacturer, the material properties of individual constituents may significantly deviate from these values when introduced into the composite. To add credibility to numerical predictions the properties derived from nanoindentation tests performed directly on the composite are adopted. The proposed synergy of experimental and numerical modeling is exploited here to provide estimates of the elastic stiffnesses of porous multilayer C/C composites with imperfect microstructure. Keywords: nanoindentation, microtomography, statistically equivalent periodic unit cell, homogenization, C/C textile composites, porosity. 1 Introduction While the application of PUCs in problems of strictly periodic media has a rich history, their introduction in the field of random or imperfect microstructures is

Keywords

nanoindentation, microtomography, statistically equivalent periodic unit cell, homogenization, C/C textile composites, porosity