| With the rapid development of coach industries, the amount of coaches increase rapidly. The massive death and injured traffic accidents had occurred sometimes owing to large passenger capacity of the coach. Although the accidents of the rollover crash take the percent of 4.2 of the total accidents while the mortality is the percent of 33. During the accidents of rollover crash, many passengers deaths are caused by serious distortions of passage coaches skeletons,break and even the ruins. Lacking of enough residual space, the passengers faced "the second crash", so the security of coach rollover body structural to be solved urgently. At present, the new edition of GB/T17578《Provisions of strength for the superstructure of bus》, according to the provisions new version of amendment ECE R66 totally. New regulations will be carried out compellingly this year, except for the test about the crash of the side-rolling whole coach, the law validates four equivalent certification methods including the computer simulations on the strength of superstructure. But the researches of security simulation study less in our country, especially the research on the security of coaches rollover body structure starts newly. Therefore, to enhance the further study of coach rollover security of structure is of great significance.This paper is mainly about the study of the simulative methods on coach rollover security, the security of coach rollover body structure along with the evaluation. As a coach for example, by the analysis of the structural characteristics on coach, thus an idea of the simulative methods on coach based on the study on the function of the capsizing and collision is had.?Using OptiStruct to simulate common conditions, check its stiffness and intensity, analysis the freedom of the modal condition, and check the reliability and effectiveness of the model.? The study to the process of the simulative methods has putting forward to a simplified method based on the process of the law of energy conservation security. Finite element model is calculated with LS-DYNA and the post outcome of it is got with HyperView and LS-PREPOST. With the simulation results, through further study of coach's distortions, energy's change, crash force and residual space, the less strong insensitive structure is the upper and the vertical waist of the coach. Especially it has a big plastic shapes on the waist of the coach, a large invasion of the top structure and the invasion of the second windshield pillar is 40. 606mm. By the further study of the body skin impact in the rollover crash tests, the absorption by body skin take a total number of 4.1%, making the intrusion reduce to 2.816mm. Body skin has a certain strengthened role to rollover body structure. According to the serious distortions on the weak part of coach body structure, an initial improvement have been putting forward to on the upper cover, side panels, waists, braces the thickness slanting materials and the thickness. The results show that it has an evident effect and it gets to the demands of rollover security regulations. Intending for the evaluation of the simulation results, this paper will analysis the present evaluative methods and use for reference with the foreign evaluative methods on the upper structure intensity and evaluate the rollover test results. The DIαvalue of the coach is1.03;the result of high class evaluation is,after the improvement the DIα=0.65,high class evaluation is,that shows the evaluation is feasible.This paper towards onto the study on the simulation methods of rollover security and put a reference to the same kind of coach experiments on rollover simulation. The result of the study builds a certain foundation to further study of the rollover crash security and offers references to the national mandatory regulations that will be implemented, to the design and improvement of coach in large enterprise. |
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