| In recent years, With the variation of vehicle types and the rapid development of highway,traffic accidents that happen on the highway is increasing year by year. Among them nearly 1/3 accidents are due to the impact between vehicles and barriers. Vehicle-guardrail crash is a nonlinear large deformation dynamic procedure, so it is a very difficult problem. The study on traffic safety is still at the starting state at present in our country, so the research work that carries on in this respect has a very realistic and great meaning.In the first, this dissertation refers to the domestic and foreign research results, base on this basis, domestic present type and characteristic of roadside guardrails are analyzed. Simulation methods of vehicle passive safety are analyzed and the basic theory of the dynamic explicit finite element analysis is described. The basic theory of the dynamic explicit algorithm is introduced. Contact algorithms, hourglass control, time-step control and the initial penetration problem are described.Secondly, the finite element model of body- in -white is built by the software of Hypermesh, it's free modal has been analyzed, and body in white of the sample vehicle has been test. Compared with testing and simulation results, the finite element model has been revised to guarantee the accuracy of the model. Based on this has established full vehicle's finite element model. According to the standard of nation and traffic trade, the finite element model of barriers is built, and the model of vehicle crash guardrail system is built. The numerical Simulation analysis of crash in full vehicle- guardrail system is carried out, and the energy curve in crash course is carried on and it's analyzed to verify the results of the analysis with higher accuracy. Combining the evaluation standard of crashworthiness, the evaluation of simulation results is carried out, and the impact performance of the two type guardrails is compared. According to GB11551-2003 evaluation criteria, the vehicle body velocity and acceleration were analyzed.Finally, for the problem of guardrail's lager crosswise deformation and resistance between the wheel and guardrail posts, and combining the characteristic of western road, the structure of two wave guardrail is improved. The protective performance of the two wave guardrail before and after improvement is compared by the finite simulation method. The result shows that the guardrail has a better protective performance and steering capability after structure improvement, and has a better effect on avoiding secondary accidents.
|
PDF Full Text Request