• Dr. Jorg Hohe
  • Fraunhofer-Institut für Werkstoffmechanik IWM
  • 209 Randolph Hall
  • 2:00 p.m.
  • Faculty Host: Dr. Rakesh Kapania

Composite materials are indispensable materials in modern lightweight construction and many other technological fields. Consisting of two or more different constituents with different geometry and material properties, they offer the possibility for a design of tailored materials to comply with a large variety of requirements deriving from the intended structural application. A special case of composite materials are cellular solids and solid foams.

In engineering application, the numerical analysis of components and structures consisting of composite materials is preferably performed in terms of macroscopic, “effective” properties rather than by using detailed models of their microstructure. The macroscopic properties may be determined either experimentally or numerically using a numerical “homogenization” approach. The main advantage of the numerical schemes is that they can be employed in a rather efficient manner for the design of custom-made materials and in screening analyses for assessing the potential of competitive microstructural designs. Especially in complex tasks of multi-objective problems in the design of materials, the experimental expenses can be reduced significantly.

The presentation is concerned with schemes for a high-precision numerical prediction of effective properties of composite and cellular materials. In a first step, the basic concepts for determination of the effective mechanical properties from the analysis of a representative volume element are reviewed. Subsequently, some recent advances are discussed, covering the numerical prediction of effective thermal properties and thermo-mechanical coupling effects as well as a prediction of effective acoustic properties. A special case in the prediction of effective properties for composite materials is the prediction of the uncertainty and scatter induced by the geometrical uncertainty of disordered microstructures. For this purpose, a probabilistic homogenization procedure is presented. The application of the different approaches is illustrated by examples related to the design of materials for lightweight construction and power generation.