Numerical and experimental studies of damage in porous materials

Metallic foams comprise a steadily growing group of porous materials and are gaining more and more importance in industrial applications. Main advantages of this innovative material are high ability of energy adsorption and high specific stiffness. Accordingly, porous materials are utilised in lightweight construction and passive safety components which requires exact prediction of the evolution of damage and its impact on the mechanical behaviour of metallic foams. Two different approaches, namely finite element investigations and experiments, are applied. The effect of damage is mathematically described by the Gurson-Tvergaard model. This formulation is based on the isotropic damage parameter volumetric void fraction. The evolution of microscopic damage, respectively increase of volumetric void fraction, can be monitored by macroscopic parameters. Therefore, e.g. Young’s modulus is utilised for the determination of damage parameters. In order to compare the numerical findings to experimental results, the finite element analysis is confined on easy to manufacture, periodic porous geometries. The intention of this work is the development of computational and experimental procedures to analyse the damage in metallic foams. In the last instance, the determination of adequate damage parameters for foams is projected.