Torsional crushing of foam-filled thin-walled square columns

Torsional crushing behavior of foam-filled thin-walled square columns were investigated analytically, numerically and experimentally. The lower and upper bounds on the torsional resistance of foam-filled columns were established analytically. Numerical simulations were carried out and showed that the presence of the filler changes the torsional collapse mechanism and gives rise to higher order sectional collapse modes, which results in a higher torsional resistance. Torsional experiments were performed and results were compared to the analytical and numerical solutions with reasonably good agreement. It was found that bonding of the foam to the walls changes the deformation mode by spreading deformation over the whole length. The corresponding torsional resistance is also larger for the first 40° of rotation. It is concluded that fitting prismatic members with the aluminum foam of a density ranging from 0.14 to 0.28 g/cm3 can double the energy absorption of a given member.