Isothermal and thermomechanical fatigue behavior of open-cell metal sponges - experimental analysis and homogenization modeling

The present paper summarizes interdisciplinary experimental and theoretical research on the mechanical behavior of open-cell AlSi7Mg and a brass sponges, particulary focusing on the fatigue behavior under isothermal test conditions and under periodically fluctuating temperature (thermomechanical fatigue TMF), the latter carried out in a self-designed temperature chamber. Monotonic tensile and compression tests were performed on these metal sponges, taking into account variation in the homogeneity and difference in the ductility of the cell strut material (AlSi7Mg and a brass). Modeling of the deformation behavior was carried out by means of a strain-energy-based homogenization approach on the basis of the open-cell 3D-Kelvin foam. This approach reveals the strong anisotropy during large deformations and was shown to describe the monotonic as well as the cyclic deformation behavior of the studied open-cell materials in a good qualitative agreement .