Analyses on bending crashworthiness of thin-walled circular tubes reinforced with internal triangular stiffeners

Thin-walled structures are commonly seen in many engineering fields, and their mechanical properties attract increasing interest from researchers. Thin-walled tubes are apt to flatten, especially crushed by a transverse load, which greatly decreases their global load-carry capacity. Investigations have shown that it is favorable to reinforce the thin-walled tubes to enhance their load resistance at the cost of small increase of structural mass. For this purpose, a novel reinforcing method called triangular stiffening to empty circular tubes is proposed, and the influence on the three-point bending crashworthiness is studied using finite element modelling with the aid of ABAQUS/Explicit code. The finite element model for the case of empty tube is verified by experimental results. According to the two popular crashworthiness indicators including SEA (Specific Energy Absorption) and CLE (Crash Load Efficiency), the tubes reinforced by the triangular stiffeners have an advantage over the two reinforcing methods suggested by previous literature. Deformation mechanism of triangular stiffening is demonstrated in terms of the comparison with corresponding empty tubes. The impact of three parameters including thickness, length and intersecting angles of stiffeners on the bending crashworthiness is analyzed and discussed in detail.