Axial splitting of conical frusta: Experimental and numerical study and crashworthiness optimization

This paper investigates the axial splitting process of thin-walled conical aluminum frusta, experimentally and numerically. The specimens were prepared using the spinning method and some edge slits were created at the specified locations. The specimens were axially compressed between a rigid plate on top and a rigid conical die at the bottom using Zwick universal testing machine. Some key parameters of energy absorbers such as specific absorbed energy (SAE), non-dimensional load-carrying capacity (NLC) and undulation of load-carrying capacity (ULC) were extracted from the load-displacement diagrams. Effects of different parameters such as specimen wall semi-apical angle, die semi-apical angle, number, and length of initial slits were studied on the energy absorption capability of specimens. The numerical analyses were performed by finite element method using Abaqus/Implicit software package. The surface-based cohesive behavior technique which works only with implicit solver was employed for cracks propagation. The numerical simulations were compared with experiments and good agreements were found between numerical and experimental results. To find the optimum energy absorber parameters, the design of experiments (DOE) method was employed. Using the existing data and applying the Taguchi technique, the optimal specimens with best SAE, ULC, and NLC were found. To check the efficiency of the DOE approach, these specimens were fabricated and tested and it was observed that the tested specimens had the best SAE, ULC, and NLC among all specimens. So, the excellent performance of DOE technique in present application was proved.