Lightweight Design And Crash Safety Research Of Vehicle TRB Structures

With the auto production and ownership increasing, energy, environmental protection and safety have become three big problems to be solved urgently in the auto industry. However, the effective solutions are realizing the automotive lightweight and improving the vehicle safety performance. In order to coordinate the contradiction of automotive lightweight and crash safety, a comprehensive method of the finite element, crash simulation and modern optimization design is used in this paper. Then, the tailor rolled blank technique is applied to the important anti-collision parts of vehicle body, such as the front rail and door impact beam. Otherwise, a reasonable and effective solution is proposed.Firstly, according to the modeling process, the finite element model of the vehicle is established by the pre-processing software Hypermesh. Then on the basis of the test standard of C-NACAP and Euro-NCAP, the model of front collision and the model of side impact between vehicle and rigid column are established respectively. Meanwhile, in order to avoid the workload increasing greatly resulting from the time consuming of the vehicle collision simulation, the whole structure of the front rail is extracted from vehicle model as the simplified model for optimized design, which contains the front bumper, the absorbing box and the front rail. In the same way, the door system is extracted as the simplified model for optimized design of door impact beam. And the vehicle model is used to validate the final results of optimization.Using the simulation software of LS-DYNA and MATLAB, and combining the orthogonal experiment design method with the response surface approximation model method, the lightweight optimization design is respectively carried on the front rail and the door impact beam in this paper. First, the front rail is divided into four parts according to its stress distribution under the gravity load and the reinforcement plates distribution. The thickness of every part is taken as the design variables to carry on orthogonal experiment design. On the basis of the simulation results of the sample points, the response surface approximation model is established, which includes mass, energy absorbed and peak force. Then, the mathematical model of optimization is set up with the goal of minimizing mass and the constraint of energy absorbed and peak force. Otherwise, the optimal solutions can be obtained by the optimization function of MATLAB. Finally, validating the lightweight design by vehicle collision simulation, we found that the quality of optimized front rail reduced 1.1kg, weight lost 7.8% compared to the original design. In the same way, the quality of optimized door impact beam reduced 0.23 kg, weight lost 13.8%.The results show that the tailor rolled blank technique applied to automotive anti-collision parts, can realize the lightweight design under the premise of its crashworthiness and the effect of weight-loss is significant.