Research On Dynamic Performance Of Vehicle Seatbelt By Test And Simulation

The rapid growth of domestic car ownership has brought tremendous pressure to road traffic safety around the country.The number of traffic accidents has shown an upward trend,bringing irreparable loss of people and property to the country and individuals.Passive safety measures are also important measures to protect occupants'safety while improving drivers'safety awareness and active safety performance of vehicles.As a simple,economical and effective protective measure,seat belt is an important part of passive safety system of automobile.In this paper,the dynamic performance of seat belt was studied by experiment and digital simulation.The development of relevant standards of seat belt and the main influence of dynamic test were discussed.The dynamic performance of seat belt was studied by means of test method through vehicle collision test system.The simulation model of vehicle seat belt was established,and the damage evaluation index of dummy and the protection effect of seat belt were analyzed.This paper studied the relevant test regulations of seat belt and restraint system in China,analyzed the improvement requirements of new standards in the aspects of ribbon,buckle,adjuster,connector,height regulator,winder and assembly,explained the difference between the new standards of domestic seat belt and European standards,and studied the selection of dummies.The influence of calibration,seat belt placement and other factors on the performance of seat belts was also analyzed.The results showed that the new and old standards differ from each other in terms of experimental equipment,experimental process and standard limits.The differences between the new standards and European standards are mainly reflected in the different requirements for pre-tensioned seat belts and seat belts with force limiters.The dynamic performance of seat belt was studied by collision test.The calibration process of the test system was discussed.The acceleration of the test bench car varies with time.The change process of dummy response with time was analyzed.The improvement scheme and influencing factors of seat belt were revealed.The results showed that the accuracy of the acceleration sensor of the test bench car met the impact test standard of SAE J211instrument.During the real-time acceleration process within 80ms,the seatbelt assembly components did not break,and the buckle or locking system did not fail.The chest displacement and hip displacement of the double pre-tightened seatbelt were the smallest,and the hip position is in front of the seatbelt.The displacement was 45 mm and the chest position was 36mm.Aiming at the frontal crash process of trolley,MADYMO was used to establish the protection simulation models of seat belts with different pre-tightening modes for dummies.The load exertion method was studied,the accuracy of the simulation model was verified,the evaluation index of dummy damage was summarized,and the protection effect of seat belts was analyzed by digital simulation.The results showed that during the collision of the automobile,under the protection of no pretension,buckle pretension and bilateral pretension seat belts,the injury values of dummies calculated by HIC₃₆ were 636.8,454.7and 362.4 respectively;the T3MS values were 403.5 m·s^-2,365.6 m·s^-2 and 338.2m·s^-2respectively;the Thpc values were 37.2 mm,35.3 mm and 34.8 mm respectively;and the synthetic acceleration of hip wes 34.8 mm.The values were 484.8 m·s^-2,420.2 m·s^-2 and425.3 m·s^-2,respectively.Compared with the seatbelt without pretension,the protective effect of the seat belt with buckle pretension and bilateral pretension on the occupants was greatly improved;the protective effect of bilateral pretension on head,chest,upper neck and leg was higher than that of the seat belt with buckle pretension,and the protective effect on hip was worse than that of the seat belt with buckle pretension.