Effect of the cross-section on the energy absorption and bending behavior of bent tubes

When a bent tube is subjected to a transverse load, it has the capacity to resolve this load into both axial and bending components, allowing the structure to achieve a combined stress state.This confers higher structural efficiency compared with straight tubes.The crashworthiness performance of bent tubes depends on multiple factors such as material, configuration, and geometric parameters.However, studies on the cross-section of bent tubes have rarely been reported, despite their superior performance compared to their straight counterparts under bending loads.The current article first evaluated the mechanical response of a straight tube versus a bent tube.Subsequently, a second numerical analysis evaluated the effect of the cross-section on the bending resistance and energy absorption of bent tubes.For this purpose, five bent tubes with different cross-sections, including circular, triangular, square, and rectangular shapes, were numerically evaluated using three-point bending tests.In all cases, the bent tubes had the same geometric characteristics and mass.During the simulations, the tubes were assigned an elastoplastic material model for aluminum alloy 6063-T5.The reliability of the numerical results was confirmed through the experimental validation of a circular straight tube subjected to a three-point bending test.According to the results, the effectiveness of the bent tube with respect to the straight tube was confirmed, with an E a improvement of 22.84%.Furthermore, the importance of the cross-section in the crashworthiness performance of bent tubes was demonstrated.The best crashworthiness performance was with the circular cross-section, which achieved a CFE value of 0.87, representing a 13.14% improvement with respect to the lowest CFE obtained for the rectangular bent profile (BR-01).