Compression and impact behaviors of twisted cellular thin-walled tubes

Thin-walled tubes have exhibited extraordinary advantages in lightweight and energy absorption for impact scenarios. In this paper, several new twisted cellular thin-walled tube structures were designed and studied. The configurations are obtained by twisting hexagonal, re-entrant, and square. Effects of twist angle and porous types on the compressive behaviors of the structure were studied by experiments and finite element models. Then, effects on the deformation modes, specific energy absorption (SEA), and crushing force efficiency (CFE) of thin-walled tubes at different crushing velocities were analyzed. The finite element models are established, and the finite element simulation results are verified by experimental results, which are in good agreement. Results show that twist angle and crushing velocities have significant effects on the compression behaviors of twisted thin-walled tubes. And when the twist angle exists, the instability direction of the thin-walled tube sample will change with the twist angle. The instability direction is generally the middle of the symmetry axis between the top surface and the bottom surface. Under quasi-static compression, the force-displacement curves obtained when twisted thin-walled tubes are compressed are not similar, and there is no obvious law for SEA and CFE. When the crushing velocity becomes larger, the influence of the overlapping region (OR) becomes obvious and the crushing process becomes more stable. The force-displacement curves are similar for the three porous types, and SEA and CFE are regular due to the influence of overlapping regions.