The Mechanical Behaviour of Aluminium Foam Structures in Different Loading Conditions

Foams are one of the best solutions for energy absorption enhancement. Many types of materials can be produced in the form of foams, including metal and polymers. Among metal foams, the most advanced are aluminum based. They couple lightweight with good properties, not only mechanical, but also, for example, good thermal stability. Among the various aspects still to be investigated regarding their mechanical behavior, there is the influence of a hydrostatic state of stress on yield. Unlike metals, the hydrostatic component affects yields. Therefore different loading conditions have to be considered to fully identify the material behavior. Another important issue in foam structure design is the analysis of composite structures. To this purpose an aluminum foam has been examined (FOAMINAL, provided by IFAM within the 6^th Framework Programme European Project APROSYS). The material behavior has been investigated by subjecting the foam to different stress state conditions (uniaxial, hydrostatic, pure deviatoric, and various combinations). Results obtained in various kinds of test will be presented: uniaxial compression, in quasi-static and dynamic conditions loading the components into a SHPB device, tension, bending, and shear loading. Moreover, composite structures were made by assembling the foam into aluminum cold extruded closed section tubes (in 6060 aluminum). All the results show that the energy absorption capability of the composite structures is much greater than the sum of the energy absorbed by the two components, the foam and the tube.