Collision Simulation Research On Rear Underrun Protective Device Of Trucks

As automobile collision safety issues is gradually drawing more and more attentions,people want to be able to take some effective measures such as improving the crashworthiness of automobile body structure or increasing safety devices to reduce the degree of casualty accidents to the lowest.Rear-end collision is relatively more common forms of traffic accident,especially car rear-ended truck takes the highest proportion.Because crash compatibility between car and truck is very significant,the truck without install rear underrun protection device or strength of the rear under-run protection device is insufficient,once rear-end collision occurs,which will cause great threat to the driver's life.Therefore the research on rear under-run protection device has a great significance to improve crash compatibility and reduce the traffic accident casualties.Computer simulation method is mainly used in this paper,first the finite element model is established based on the rear underrun protection device of a domestic heavy truck,and then crash simulation study is taken according to the standard GB11567.2-2001.The simulation result shows that this rear underrun protection device not only don't meet the national standard,but also cushion energy absorbing property is very poor,rebound acceleration of the rear vehicle is quite high,and is so easy to cause great harm to the rear vehicle and its occupants.According to the shortcomings of the typical rear underrun protection device,in order to increase cushion energy absorbing property and improve crash compatibility,the theory of the law of conservation of energy and the characteristics of the rear-end collision is applied to develop a new rear underrun protection device of gradual energy-absorbing.and the dynamic collision test is done on the basis of regulation,the result demonstrates that this new type meets the requirement of the regulation.Next the initial speed is increased to achieve the feature of energy absorbing gradually in the collision,and the occurrence of underrun can be prevented in the 50% offset collision.Then the features of blocking and cushion energy absorbing are checked by making the collision simulation of different speed and eventually the collision simulation experiments for different angels with real car models are done to prove that this new rear underrun protection device has a good effect on improving crashcompatibility.Finally,HyperStudy software is used as the platform for optimization to obtain the best combination of thickness,which based on the multi-objective genetic algorithm and the method of experimental design and approximate model to make the structural optimization.The structure parameters is modified according to the optimization results and submit it to LS-DYNA.Compared to the original model,the effectiveness of the optimization is obvious and also verify that the optimization method based on approximate mathematical model is effective and reasonable.