Optimization of two segments crash box with rubber joint using response surface methodology

Abstract

The development of the crash box as a passive safety device has been carried out. Based on previous studies, it was known that the two segments crash box had the highest energy absorption compared to the one segment crash box. This study aims to determine the effect and the optimum condition of design parameters to specific energy absorption (SEA) on two segments crash box. This study is carried out using a finite element software with optimization methods using response surface methodology. The design parameters used are a segment diameter (D), upper segment thickness (Ta), lower segment thickness (Tb), and connection location (L) of two segments crash box with each parameter consisting of 3 levels. Crash box testing refers to the drop mass test. The impactor with 103kg mass drop the crash box with speed of 7.67m/s. The results showed that the specific energy absorption was decreased with larger segment diameter and the lower segment. The lower segment thickness has the most significant effect on the specific energy absorption. The smaller specific energy absorption was occurred for Ta ≤ Tb, and the greater specific energy absorption for Ta > Tb. The optimum two segments crash box is denoted for design parameters: D = 70mm, Ta = 2.5mm, Tb = 2.5mm, and L = 30mm which has the specific energy absorption of 32,266.47J/kg and force reaction of 100,905.24 N.