| As an important safety component linking occupant with vehicle body, automotive seatplays a decisive role for the protection of occupant safety as one of the key component forthe automotive passive safety. Meanwhile, the occupant injury degree could be reduced inaccidents by reasonable design of the automotive seat. Avoiding structure damage andfunction fail are seen as the safety design goal of the automotive seat. However, current seatsafety test regulations and related research are only focused on individual seat system, withthe automotive crash environment ignored, which is difficult to accurately reflect the realload distribution of seats in crash. Therefore, it is of great engineering significance andpractical value to analyze the strength and stiffness of seat on seating state in frontal crash.Two front seats, developed by a domestic seat manufacture were selected as the objectseat, the strength and stiffness of which were analyzed in actual front crash environmentwith FE method. According to the shortage of strength and stiffness existing in the seat, theseats were improved. First of all, appropriate simulation platform was chosen for FEsimulation, the FE pre-process software Hypermesh was used to establish the FE model ofseats. Tests such as seat static strength test, headrest backward displacement test andheadrest shock absorption test were conducted based on GB15083and GB11550. Headrestimpact and cushion pressure tests were simulated with reference to the above seat tests. Bycomparison of the experimental and simulation results, the FE models of seat were validated,which could be used for further research. Then FE models of dummy, safety belt and airbagwere established and integrated into the model of a domestic sedan body which had beenvalidated. By adjusting the relative position of sub models, dummy positioning and sittingposture, cushion preloading and contact definition, a complete and effective automotive FEmodel of front crash were established.Based on the above automotive FE model of front crash, automotive100%rigid wallfront crash at56km/h speed was simulated with dynamic analysis software LS-DYNA. Thedynamic responses of driver and passenger dummy were obtained as well as the strengthand stiffness characteristics of seat assembly parts. According to the shortage of strengthand stiffness existing in the two seats in front impact, the seats were improved by threemethods of replacing high strength material, increasing sheet thickness and strengtheningsupport. Then the improved model was simulated, and the results showed that maximumstress of every part of the improved seats decreased obviously, were in the extent of materialstrength, and the distribution of stress were more reasonably. Therefore, the strength and stiffness of automotive seats are reinforced feasibly, the danger of function fail owing to theshortage of strength and stiffness in front crash was eliminated, and the protection effect ofseat for occupant was improved greatly. |
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