The Study On Safety Simulation Of A Sedan Car In Small Overlap Frontal Collision

Nowadays, car accidents threaten everyone’s property and life safety all the time. Although the frontal collision test of many vehicle models at present result in excellent performance, the expression in actual traffic accidents is barely satisfactory without avoiding serious injuries and casualties of the passengers. IIHS announced the offset collision test with the overlapping ratio of 25% in 2012, in the hope of bringing the collision safety of small overlap to the attention of car manufacturers.This thesis has introduced the fundamental theory of vehicle collision simulation, analyzed the reason of the extensive use of display time integration method in car collision simulation and expounded the reduced integral unit and the brought-about hourglass phenomenon in display time integration method. In addition, introduction has also been conducted on the algorithm and control of the step size of critical time in display time integration.The thesis takes the finite element model of the finished automobile of Yaris 2010 announced by NCAC as object of study. Based on the frontal collision test with the overlapping ratio of 25% brought about by IIHS, the finite element model of finished automobile frontal collision has been set up. By applying the finite element method of display nonlinear, frontal collision simulation with small overlap has been carried out to resolve deformation in the finished automobile and key components and the changes of velocity, acceleration and energy. Through the analysis on the simulation result, it can be known that the leading energy absorption component in the frontal collision has had its front rail split with the rigid barrier, which gives rise to excessive intrusion of the passenger compartment.The thesis has put forward crashworthiness improvement scheme specific to numerical simulation result of frontal collision with the overlapping rate of 25%: to increase the intensity of the related components surrounding the passenger compartment and to add crossbeam surrounding the front end panels as horizontal power passage. By comparing the deformation simulation results of threshold beam, door frame and front end panels before and after the improvement, it can be known that the scheme has reduced the intrusion to the passenger compartment, which has proved the feasibility of the safety improvement scheme.Eventually, low-speed collision simulation has been conducted specific to the working condition of collision with low overlapping ratio, and simulation results of front parts, bumper, crash-box and front rail have been analyzed, and all deformations meet the requirements of RCAR.