Bending collapse of optimal arched thin-walled structures

Arched thin-walled structures are quite promising to significantly improve the bending resistance of beams under transverse loading since they can switch transverse forces to axial ones. The crashworthiness of a type of optimal arched structure with circular section (OASCS) is investigated in this work. Static and dynamic three-point bending tests show that OASCS specimens exhibit nearly 5 times the energy absorption and specific energy absorption (SEA) of corresponding straight tubes. Metallic OASCS must be fabricated by some metal forming process, which has an important influence on crashworthiness. Numerical simulations of the tests are then carried out by using LS-DYNA, and the results agree well with the experiment. The fabrication process of OASCS is simulated by LS-DYNA, and the simulation results are in good agreement with the experiment. The forming effects result in a 20% increase in SEA of OASCS. The effects of boundary conditions and structural parameters are also investigated numerically. It is interesting to find that the response of OASCS is insensitive to the span, which is the most critical factor in three-point bending. Crashworthiness optimization and partial multi-cell enhancement are also employed to further improve the performances of OASCS, which leads to about 40% and 60% increases in SEA, respectively. Finally, the application of OASCS to a bumper system is considered in pole crash analyses.

Automated summary

Arched thin-walled structures have the potential to significantly increase the bending resistance of beams under transverse loading by converting transverse forces into axial forces. This study investigates the crashworthiness of an optimized arched structure with circular section (OASCS) and finds that OASCS specimens exhibit nearly 5 times the energy absorption and specific energy absorption (SEA) of corresponding straight tubes. The forming process of OASCS has a 20% increase in SEA. The response of OASCS is found to be insensitive to span, and crashworthiness optimization and partial multi-cell enhancement further improve the SEA by about 40% and 60% respectively.