Compressive performance evaluation of APM (Advanced Pore Morphology) foam filled tubes

The aim of this paper is to study the uniaxial-compressive crush performance of thin-walled structures filled with Advanced Pore Morphology (APM) foam elements, exploring their deformation and failure mechanisms. The APM-foam elements are integral-skin closed-cell foams of near spherical shape fabricated through the Powder-Compacting-Foaming method by heating precursor in a continuous belt furnace. Two lightweight structures using the APM-foam elements were assembled, tested and evaluated: (i) Al-alloy tube filled with non-bonded APM-foam elements and (ii) Al-alloy tube filled with polyamide-bonded APM-foam elements. Non-bonded APM-foam filled tubes were prepared by pouring the APM-foam elements into an empty Al-alloy tube (without any bonding). Polyamide-bonded APM foam filled tubes were prepared by pouring the APM-foam elements coated with polyamide into an empty Al-alloy tube and then submitted to a heat treatment curing the polyamide. The axial crush performance of the APM foam filled tubes was compared to that of the empty tubes (with and without heat treatment) and tubes filled with conventional closed-cell foam. The results show a significant influence of the adhesive bonding on the compressive behaviour of polyamide-bonded APM foam filled tubes, which exhibit controlled deformation behaviour without appearance of cracks and show superior specific energy absorption per mass unit.