Simulation Research On Structure And Restraint System Of Certain Car In 25% Small Overlap Frontal Crash

In many frontal crash accidents,for example the left anterior corner of an vehicle impacts with the right anterior corner of another vehicle,oblique collision or narrow collision(impact with trees or poles),because of limited engagement of frontal structures,it can still cause occupant death even with seat belt and airbag.This kind of accidents are named “Small Overlap Frontal Crash”(SOFC).Because the bumper and front side member of most vehicles don’t engage in,the impact energy transfers to the tire assembly,leading to the tire assembly failure or intruding into compartment,with results of the direct injury of occupants.Therefore it is necessary to study SOFC.Taking a sedan car for this study,a set of structure optimization processes were proposed for SOFC by using the finite element model of this vehicle,and the restraint system was matched for the final optimized model.Firstly,the testing and rating protocols proposed by Insurance Institute for Highway Safety(IIHS)for SOFC was introduced,and the testing for SOFC is called 25% Small Overlap Impact(SOI).Then the SOI condition for this model was established by hypermesh and analyzed by LS-DYNA.By benchmarking the experimental data and the simulation data.the model was proved to be reliable.Then the crashworthiness was analyzed and rated by the testing and rating protocol,the problems of the base model in crashworthiness was revealed,and multiple locations of the vehicle was selected to set cross section to measure the section force and to find the load transfer path according to the peak time of this section force.By analyzing the section force,the essential of the crashworthiness problems was revealed to make a specific structure optimization program.Using this program,an optimized model was obtained.Comparing the base and optimized model and analyzing the section force of the optimized model,the essential of the structure optimization program was revealed,Finally,the Stiffness matching of main structural members was conducted as further optimization.By comparison of the optimized model and final optimized model,the stiffness matching program was proved to be true.After performing structure optimization,occupant-restraint system was established to match the final optimized model.By using orthogonal test,the parameters of constraint system and dummy kinematics were optimized.To verify our hypothesis,the structure crashworthiness,the dummy injury,restraint and dummy kinematics,were evaluated.