SIMULATION OF CRASH TEST OF A SALOON CAR WITH SKIN PANELS MADE OF IF AND AHS STEEL

Abstract

Car crash test analysis is widely performed to determine the level of safety provided by the car to its passengers. This thesis focusses on the similar study. There are several factors which contribute to the safety of passengers, specially front seat travellers based on which the star ratings are provided to every car by the standard testing organisations. The study involves all the standards as set by NCAP and also uses the model of Toyota Yaris with the conditions and specifications assigned to it by NCAP officially. The FE model was observed on the software LS-Dyna. The study of the car involves material change for the skin and frame of the car on software. The new material whose specifications were used on the software were IF (Interstitial Free) steel for the skin material and AHSS(Advanced High Strength Steel) for the frame which require comparatively higher strength. The tensile testing results were obtained which were helpful in defining the Load Curves for the respective materials. The load curves were used in the software simulation for definition of material deformation in its plastic state. The simulation in full frontal orientation which is one of the standard tests involved in Crash analysis was performed with changed material. The results and observations have been limited to the materials’ properties during impacts. Although there are numerous factors which involve the safety of a vehicle, the focus was primarily on the skin and frame material change which can increase the crashworthiness and make vehicle safer. The crash pulse and energy absorption was primarily focussed directly v determining the materials’ effectiveness in crash. Also, the deceleration curve and velocity curve for the driver’s seat was drawn with respect to time in order to determine effect of the change of material on the shock propagation through the car body. The net increase in the energy absorption was slightly less than 2 percent which is small but significant taking into the account of others parameters which have been excluded like the change in parameters for the Cowper-Symonds material model. Also, the average decrease in acceleration and velocity of the driver’s seat was less than 2 percent too. Along the thesis, the reason can be discerned behind this increase and decrease which is primarily based on the limitations and assumptions. Based on those results, the thesis concludes the study with the scope of work that can be done in future with relaxation in the limitations.