A Research On Crashworthiness Of Mini-Bus Based On Front Rail Structural Analysis

In the development phase of new car, safety has been the focus ofattention. The deceleration response and deformation of car body in crashstage is determined by the front rail, which is the main energy absorbingcomponent. So, it is significant for the improvement of rail structuredesign and vehicle crashworthiness to deep understand the longitudinalstructure features.In the background of a mini-bus crashworthiness improvement, thefront rail and its connection structures of mini-bus are systematicallyresearched through theoretical and simulation analysis.Specific work is as follows:1. The FEA model of mini-bus is established. Then, front crashsimulation is performed.The analysis results suggest some structuralproblems. To solve these problems, some improvement ideas are putforward.2. The effect of global features( wall thickness, section dimensions andmaterial properties ) on the crushing stage are researched.1) The expression of mean crushing force is developed for top hatthin-walled tube. Theoretical predictions of the expressionshows better results than previous predictions. The formulassuggested, wall thickness than section dimension, can influencethe effect of rail energy absorbing.2) According to the experiments in the references, top hatthin-walled tube FEA model is set up. Quasi-static and dynamicanalysis are performed. The results of simulation are consistentwith the experiments.3. The effect of local features (dent and hole) on the crushing stage are researched. Analysis results show that, compared with surface hole,the influence of dent on peak force is bigger and the mean crushingforce can be increased by increasing the number of dents.4. The effect of connection structures (front crossbeam, railreinforcement, post, and so on) on crushing stage are researched.Analysis results show that, independent front crossbeam is better thanintegral one; and the mean crushing force can be affected greatly bythe front cover and reinforcement.5. According to the above analysis, after some rounds of simulationcaculation, an improved scheme is proposed.The optimized model isput forward.Conclusions of this dissertation can be important references forfront rail structural improvement and mini-bus crashworthiness optimization in the future.