On the bending force response of thin-walled beams under transverse loading

In lateral crashes, thin-walled beams may collide with impactors with multifarious shapes and sizes at any position or angle. In addition, the beams are always fixed on other structural components. However, these facts are ignored in the present studies on the bending collapse. This paper aims to investigate the influences of such factors on the transverse bending responses of thin-walled beams. Quasi-static three-point bending tests are conducted first for aluminum square beams loaded at different load angles, positions and spans. The non-linear finite element code LS-DYNA is then utilized to simulate the tests. After validated by the experiment, the finite element model is employed to perform parametric studies to investigate the influences of various factors on collapse responses of thin-walled tubes, and the ranges of the force responses with the variation of these factors are discussed. Results show that the variation of punch shape and size, load position and angle may lead to the switch of deformation modes, while the loading velocity and the height of crash boxes have very small influences on the deformation patterns. Increasing the loading velocity results in a much higher peak force, and fixing the beams on shorter crash boxes achieves a higher force level. In all cases, a sharp punch perpendicularly loaded in the middle of the span controls the lower bound of the crushing force, while the upper bound is governed by the punch approaching the support with small angles. The mean crushing force of the beams can be increased by up to 78% with the variation of the load and boundary factors in the calculations. The findings of this work would be helpful on the crashworthiness design of thin-walled beams under transverse loads.