An experimental validation of numerical model for top-hat tubular structure subjected to axial crush

Abstract

Vehicle crashworthiness is an important aspect to consider when designing a vehicle to ensure the safety of the occupants. Besides this, vehicles are also designed to reduce weight for better fuel economics. One possible approach to reducing weight without compromising vehicle safety is by looking at new designs and usage of composite materials, along with the usage of computational models to reduce time and cost. Hence, this paper displays the experimental results of a carbon fiber reinforced closed top-hat section subjected to both quasi-static and dynamic crushing loading. The results were used to validate the computational model developed in the study. The specimens were made of carbon composite prepregs MTM-44 sheets stacked at the alternative orientation of ±45° and 0°/90°, where 0° direction coincides with the axis of the member. The samples were prepared by using a mold and carbon prepregs under vacuum bagging followed by curing in an autoclave. Trigger initiation was applied to ensure the specimens demonstrated a stable crushing mode of failure during the test. Experimental investigations were carried out under the ambient conditions with different loading conditions, and different kinetic energy ranges (2, 3 and 6 kJ). Experimental data was used to validate the finite element analysis (FEA). The maximum errors obtained between experimental and FEA for mean load, mean energy absorption, and crushing displacement were 13%, 13% and 7%, respectively. The numerically obtained results were in strong agreement with the experimental data and showed that they were able to predict the failure of the specimens. The work also showed the novelty of using such structures for energy absorption applications.