A numerical and experimental study on the impact behavior of box structures

The safety factor of a vehicle mostly depends on the behavior of frontal automotive structures during crash. These structures, which are usually prismatic thin walled structures and are defined as crash boxes, are the main energy absorbers of the crash. Crashworthiness of these structures depends on their dimensions and materials. In this study, the impact behavior of the crash boxes made of steel and aluminum materials are investigated experimentally and numerically. The crash tests are performed by using a drop test unit. The crash test is also modeled using the ANSYS finite element software. The crash box is discretized by using shell elements. The deformations as a result of crash tests are compared with the finite element results. The impact force during the crash is also compared with the forces obtained using the finite element method. The results are found to be in an agreement. The impact behavior of a hybrid box made of steel and aluminum is also investigated numerically. The analyses are performed changing the parameters such as aluminum thickness, aluminum to steel weight ratio. The hybrid crash box is optimized based on the deformations to obtain the minimum weight.