Finite element modeling of non-conventional energy dissipating systems using metallic like-composite tubular structures

This work focused on a numerical modeling of innovative non-conventional energy dissipating systems developed and tested experimentally in [1] to enhance their energy absorption capacity. The basic concept utilized the axial plastic buckling of right-circular mild steel like-composite tubes with various case-hardened patterns. Such a heat treatment has been applied on 15% of the outer surface with a depth of 0.5 mm. In this work, a nonlinear finite element modeling was conducted describing the response of such tubes targeting particularly their behavior along the tube thickness. The S4R shell element of 1 mm size was used looking for an accurate mesh convergence. A contact with a dry friction penalty was highlighted by the contact between the tube surface-to-surface and the tube-to-rigid bodies. The mass scaling technique was also considered to increase the stability time. Four case-hardened patterns of 2, 3, 4 and 5 rings and two other vertical strip patterns of 2 and 3 strips were modeled, simulated and compared with the experimental data. Moreover, a numerical design platform with several new case-hardened patterns was proposed. Among the latter, two patterns (12C and 3R3V) showed better energy absorption capacities than the others even for those observed experimentally. Actually, they offered a gain in the energy absorption capacity of 42% compared to the conventional case.