Numerical and experimental analysis of cellular materials

Within the scope of this thesis different cellular materials such as sintered metallic hollow sphere structure, sintered metallic fibre structure, lotus-type material, open-cell sponge m.pore® and closed-cell foam Alporas® are investigated. Mechanical properties at small deformation (e.g. Young’s modulus and 0.2 % offset yield stress) and the effective thermal conductivity of these materials are studied. These properties are determined with the help of a novel method which is capable of simulating the real structure of the material. In this, the real sample is scanned and the micro-computed tomography images obtained are transformed into a computational model by converting the 2D images into a 3D structure and generating a volume mesh. Then the simulation model is defined by assigning material properties, boundary conditions and the appropriate load case. The advantage of this simulation method over experimental testing is the repetition of calculations and therefore a precise characterisation of the complex material structure is possible by investigating different spatial directions on the same sample. The accuracy of the simulation models is verified with a numerical convergence analysis and experimental testing. In the case of experimental testing, mechanical properties are determined with an uniaxial compression test and the thermal conductivity with steady-state plate method and transient plane source method (i.e. Hot-Disk® method).