Dynamic compression of aluminium foam derived from infiltration casting of salt dough

• First dynamic mechanical characterisation of infiltration-cast aluminium foam.
• Properties and deformation mechanisms observed by experiments and FE analyses.
• Numerical finite element analyses were based on micro-computed tomography.
• Numerical results and infrared imaging indicate layer-wise collapse.
• Insight in the micro-deformation behaviour and anisotropy has been provided.

This paper addresses the dynamic mechanical characterisation of infiltration-cast aluminium foam. The material is produced by combining melt aluminium with salt precursors which are removed after solidification. The resulting aluminium foam allows controlled energy absorption and hence is of high interest for impact engineering applications at high strain rates. In this study, experimental and numerical analyses are combined to quantify its effective material properties and investigate relevant deformation mechanisms. First, uniaxial compression tests are conducted for both quasi-static and dynamic loading velocities. The comparison of the test results permits a direct evaluation of property changes due to the loading velocity. Under dynamic loading conditions, infrared imaging enables the localisation of concentrated plastification and provides important insight into the dominant deformation mechanism. Additional numerical finite element analyses were based on micro-computed tomography imaging of actual samples to accurately capture the complex foam geometry. Whenever possible, numerical findings were verified by comparison with experimental data. Both numerical results and infrared imaging indicate layer-wise collapse as the main deformation mode. Furthermore, the numerical results provide insight in the micro-deformation behaviour of analysed foam and allow additional evaluation of the strain rate sensitivity and the anisotropy of mechanical properties.

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