Experimental and multi-scale analyses of open-celled aluminum foam with hole under compressive quasi-static loading

Compressive stress-strain behavior of open cell aluminum foam has been investigated using experimental and multiscale modeling methods. Mechanical behavior of cellular materials intensively depends on their microscopic structure and architecture which may degrade under loadings. To analyze the mechanical response of a full scale and complex aluminum foam component, one may develop multiscale modeling. In this way the degraded material properties are calculated through the analyses of a representative volume element (RVE) considering the micro-structural characteristic, architectural parameters and loading. In this study, open-celled AA6101-T6 aluminum foam is considered for the analyses. Geometrical characteristics of the foam using microscopic images are extracted, including thickness of cell walls, cell size, relative density and cross section of cell walls. The micro model is defined as RVE with nonlinear geometric and material behaviors considering the possible contacts between struts and it is conditioned on macroscopic quantity using appropriate boundary conditions. To validate the proposed model, different experiments have been performed for foam specimens with and without circular hole under compressive quasi-static loading. Finally, multiscale modeling has been proposed to analyze the foam components with complex and irregular shapes. It is shown that in order to model foams considering all the heterogeneities, even with larger size and having non-uniform stress field the use of currently existed finite-element and micro-structural models are not sufficient and the proposed multi-scale modeling which leads to acceptable results can be used for such analyses.