Strain-hardening and damage of foamed aluminium during tensile deformation

摘要

One of the most important targets in vehicle design is passive safety. Aluminium foam is an attractive material offering energy absorption to be used in light weight passive safety components. Foamed aluminium powder compacts are characterized by computed X-ray tomography (XCT). The cellular structure is transformed into a continuum by density mapping. The type of alloy, the mass density distribution and the skin of the foamed panels determine the stiffness, the tensile strength and the engineering strain to failure. Tensile specimens exhibit strain hardening beyond crack initiation in the samples' skin by crack bridging and load redistribution. The elastic properties of cellular specimens with skin can be described by a linear rule of mixture from the stiffness moduli of the core and the skin.