VIII International Conference on Computational Plasticity COMPLAS VIII E. O˜ nate and D.R.J. Owen (Eds) c CIMNE, Barcelona, 2005 CHARACTERIZATION OF MATERIALS WITH MICROHETEROGENEOUS STRUCTURE P. Wriggers, S. Loehnert & M. Hain Institute of Mechanics and Computational Mechanics University of Hannover Appelstr. 9A, D-30167 Hannover, Germany e-mail: hain@ibnm.uni-hannover.de, web page: http://www.ibnm.uni-hannover.de Key words: micro-macro approach, homogenization, parameter identification, inelastic materials Summary. Computational methods for the determination of material properties of mi- croheterogeneous materials including inelastic behaviour are discussed in this contribution. Applications related to this class of problems range over different length scales. These can cover up to six orders of magnitude, ranging from μm to m. Here homogenization con- cepts are employed to model the constitutive behaviour at macro scales based on results obtained at micro scales. Using the concept of representative volume elements (RVE), the theoretical background is discussed as well as the numerical treatment of the resulting complex, three-dimensional RVEs. Examples show applications within a range of materials used in engineering. 1 Introduction A description of the constitutive behaviour of heterogeneous materials such as concrete can be achieved by experimental investigations or by numerical simulations. While the Figure 1: Multi scale description of a complex material like concrete 1