Three-point bending of thin-walled arched beams with square sections

Abstract

Arched structures can fully make use of the compression properties of structural materials and significantly improve their energy absorption performances under transverse loads. On the basis of this inspiration, the bending behaviors of a type of thin-walled arched beams (abbreviated as AB) with square section are studied. Static and dynamic three-point bending tests of thin-walled straight beams (SB) and AB are firstly performed. The deformation modes show that there are primarily three energy absorbing mechanisms during the bending of AB, including indentation, bending, and axial deformation, while SB is mainly subject to bending deformation. Both the crushing force efficiency (CFE) and the specific energy absorption (SEA) of AB are found to very much better than those of SB. Numerical simulations of the tests are then carried out by using the finite element code LS-DYNA, and the simulated force responses are in good agreement with the tests. The influence of critical influencing factors on the response of both AB and SB specimens are then analyzed numerically. The factors including the boundary conditions, material failure, impact velocity, geometric parameters and sectional shape. Results show that AB outperforms SB for cylinder or L-shapes supports, but it may be superior or inferior to SB for fixed boundaries with the variation of geometric and loading conditions. Arched and straight beams with square sections generally show much better energy absorption efficiency than those with circular sections. Finally, thickness enhancement of the arc segment is employed to further improve the crashworthiness of AB.