Indentation tests of aluminium honeycombs

Aluminium honeycomb is a type of cellular material which has high strength to weigh ratio and is a good energy absorber. They are used as structural components in various engineering applications. Comprehensive study has been conducted on the compressive behavior of aluminium honeycombs. However, the research of aluminium honeycombs subjected to other type of loading, such as indentation, is still limited. In this paper, quasi-static and dynamic indentation tests were conducted to study the deformation and energy absorption of three types of HEXCELL (R) aluminium honeycombs with different cell sizes and cell wall thicknesses. Quasi-static tests were conducted by using a universal MTS machine at velocities of 0.05 mm/s, 0.5 mm/s and 5 mm/s, respectively. Dynamic tests were conducted by using a high speed INSTRON machine at a velocity of 5 m/s. Force-displacement curves were plotted in which the total energy absorbed was calculated. The deformation of aluminium honeycombs in indentation tests includes the compression of honeycomb cells under the indenter and tearing of honeycomb cell walls along the indenter edges. The energy dissipated in compression and tearing were calculated and discussed. The effects of cell size, cell wall thickness and loading velocity or strain rate on the plateau stress and energy absorption were analyzed.