Three-dimensional modeling of a two-phase material on the microscopic level

Two dimensional FE simulations (2D) are less time-consuming and less expensive than three dimensional simulations (3D) but they generally do not describe the mechanical behaviour of complex materials adequately. The assumptions of plane strain or plane stress conditions are simplifications, which can lead to unrealistic results. Three dimensional (3D) calculations require a larger number of finite elements for accurate reproduction of the real/complex microstructure. This microstructural information must be available from extensive experiments like computer tomography or serial sections. In this situation, the dimensions of the model measured in terms of microstructural length scale (e.g. inclusion size), especially its thickness is an important point. The thickness of the model should be big enough to get correct results, but a too big thickness enlarges the model unnecessarily. This paper gives a guideline, how to define the minimal dimension of the 3D-model of a particulate reinforced metal matrix composite, which provides correct results concerning local strains.