Compressive behavior and energy absorption analysis of casting skin-wrapped aluminum foams

The mechanical properties are an indispensable factor affecting the energy absorption capability of aluminum foam. In the past few decades, various aluminum foam sandwich structures, including casting skin-wrapped aluminum foams (CWFs), have been developed and proven to be effective in enhancing the integral mechanical properties. This study investigates how adding casting skin affects the compressive behavior and energy absorption of closed-cell aluminum foam. The aluminum foams were produced using the melt route and then used as the core material for manufacturing CWFs through counter-gravity casting solution after pre-heating. Axial and radial compressions were applied to columnar CWFs with pores falling within two size ranges and three ratios (D/T) of outer diameter to casting skin thickness. The failure mode of CWFs was dominated by brittle fracture of casting skin and progressive crush of foam core. Adding casting skin significantly enhanced the mechanical properties in axial compression, while it had no significant effect in radial compression, with both types of compression varying depending on D/T values. Samples with smaller pore sizes exhibited better overall performance. The influence of the addition of mass on the specific energy absorption should be considered in the design of lightweight crashworthy components.