Experimental analysis of impact absorption capabilities for the dissimilar W cross-sectioned crash-boxes designs

Although, safety precautions and vehicle technology has been developed for decades accidents can happen in a daily traffic causing collision deformations, injuries or unfortunately fatalities. These security measures can be classified under two categories: active and passive safety systems. In this study, Crash-boxes which are one of the passive safety systems including the structural improvements and compatible material selection were investigated. In order to reduce the adverse effects of the collision, the crash-boxes, which are normally placed between the chassis and the driver's safety cab can be defined as ahead of the engine axle, are intended to be located just behind the front bumper of the car. During the study, the shock energy absorbing capabilities of the new design open cross-sectioned crash-boxes with different forms of the W-shaped geometries were investigated. The scaled simulation of the real accident scenario was carried out with the free fall tests and the ability of the crash boxes designed in different size and thickness to absorb the accident shock wave was investigated. In this process, a small-class family vehicle in the A-segment was taken into account in the case of frontal collision conditions. In the collision scenario carried out with the help of free fall tests, a steel plate with a height of 2.88m and a mass of 150 kg is chosen instead of the fixed wall, while the fixed steel plate on the ground and the collision boxes placed on the ground represent the mobile vehicle. In this process, the first preferred W-section sheet metal crash-box was subjected to free fall tests for the optimization of the thicknesses and heights; then another W section sample which was determined within the designs with optimized dimensions was subjected to the same tests to determine which design is better. The dynamic simulations were carried out and validated for some of the samples in order to use the experimental data in the numerical simulations. Finally, it has been determined that the optimum sample to absorb the collision energy is the initially tested W cross-sectional crash box design having 1mm thickness made of ST37 (S235JR) material. Keywords: Crash-box, frontal collion, drop test, w section