Numerical and experimental aluminum foam microstructure testing with the use of computed tomography

Metal foams are a new, as yet imperfectly characterized, class of materials with low densities and novel physical, mechanical, thermal, electrical and acoustic properties. They offer potential for lightweight structures, for energy absorption, and for thermal management; and some of them, at least, are cheap. The paper deals with the experimental and numerical studies of the open-cell aluminum foam microstructural behavior. The aim of the research was to describe and to assess the main mechanisms that appear in the foam structure during the compression and how they influence the material energy absorbing capabilities. The research was carried out with the use of CT-scanning technique. The first step of the research was the compression test of the samples in the tomography testing stage that was coupled with sample X-ray scanning to describe the deformations in the researched material for the numerical model verification. The next step of the study was the development and the analyzes of the numerical model of tested undeformed sample in accordance to computed tomography results. The model was built with the use of a unique computer code created to transform the scan point cloud into FE raster model based on solid 8-node elements. The experimental and numerical test results were compared and showed good compatibility. The stress distributions were studied to describe the main mechanisms in the structure. The most important conclusion is that the foam structures can be considered as the complex beam constructions where the local instabilities decide about the energy absorbing capabilities.