Fillet effect on the bending crashworthiness of thin-walled square tubes

Filleting four corners of square tubes is suggested to reduce the peak force and improve energy absorbing performance. Three-point bending tests are conducted to investigate fillet radius effects employing an ABAQUS explicit code. Three cases characterized by the ratio of width to thickness are considered. Fillet greatly reduces the maximum forces compared with square cross-sections, and the normalized maximum forces decrease with increasing wall thickness when the fillet radius is larger. Additionally, the fillet dramatically improves SEA (Specific Energy Absorption). The normalized CFE (Crash Load Efficiency) significantly exceeds that of the square ones, and the normalized CLEs are almost identical with the increasing fillet radius.