Abstract

Metal foams are used in a wide range of applications, for example in energy dissipation and as lightweight materials. When metal foams are an integral part of a structure, the mechanical characteristics and their response to external load need to be well understood. To facilitate a greater understanding, we have utilized lab-based dynamic computed tomography (CT) provided by Tescan to visualize uninterrupted compression of aluminum metal foams. These results where coupled to mechanical simulations of the same samples done with GeoDict. The dynamic CT reveals the different modes of deformation like buckling or bending of struts and collapsing of cells. Moreover, the displacement and deformation of pores can be analyzed and quantified once the scan is imported into the software. The simulation of the compression of 35% is possible thanks to the voxel based FFT solver FeelMath in GeoDict developed by the Fraunhofer ITWM. By comparing simulation and scan, the simulation can be verified in two ways: first, the load curves show whether the stresses in the foam are similar in simulation and experiment. Second, the different deformation modes observed in the simulation can be compared to the deformation modes in the scan as well as the evolution of pore shapes with increasing compression. Two samples from the same foam are tested, analyzed, and simulated. In a next step the verified simulation setup could be used not only on a digital twin obtained by importing a CT scan but also on a statistical digital twin of a foam which can be digitally generated based on the geometrical analysis of the scan. The statistical digital twin can be created with the FoamGeo module in GeoDict. This opens the possibility to create digital foam structures with new properties and to predict their deformation. GeoDict can be used to perform digital parameter studies without the need of manufacturing the foam.