| 1. PrefaceAs statistical investigations shows, in our country the number of traffic accidents has increased continuously in this years, and this trend is sever. The problem of vehicle safety becomes more and more important, so it's urgent and necessary to do some research in the field.Side impact is one of the normal crash types, which cause about 21% of all harm resulting from car crash , If only consider the accidents that causes severe injury and death, side impact will account for 26 percentage, only inferior to frontal impact.Side impact crashes are more threatening to vehicle occupants, and result in a higher proportion of serious and fatal injuries .that because of the limited space between vehicle side structures and occupants, the distance is often only 30 centimeters. so the energy absorbing area of lateral is more less than the frontal and rear area.The study of occupant restraint system is one of the main contents in the research of vehicle passive safety. The study content of occupant restraint system contains the development of side airbag , safety seat and the optimization of door and pillar. Now such study in our country developments recently, but has already become the hot topic. Besides the vehicle and sled impact test, the computer simulation is also important and can't be substitute to research occupant restraint system .This method can not only reduce the number of test, save cost, but also used in concept design and shorten the development cycle.2. Main content of this paper2.1 The Creation and Validation of Occupant Restraint System Model in Side ImpactThis paper creates a vehicle side impact occupant restraint system model using MADYMO3D, The software which is based on Multi-body theory can effectively simulate the impact process and the injury of occupant.The model consists of three parts, the car module, the MDB module and dummy module. Car and MDB module base on the real structures. Euro-SIDE-1 dummy come from the dummy family of Madymo's .Before crash simulation, dummy adjusted pose in the field of gravity. The simulation carried out accord with the ECER95. The correlation between simulation and real test is regarded as efficient if the error is about 85 percent. Based on the results of real test, the validation of the deformation, the deceleration and the biomechanical response of dummy is done. The correlation shows that the model created is effective, and the modification can be processed on the basis of this model.2.2 The Key Techniques of Creating the Multi-body Occupant Restraint System ModelA large amount of parameters are needed for creating the model, the most important parameter among them is the joint stiffness parameter, and hard to get accurately. In side impact, bending deformation is the main collapse mode of side structure, the mechanical characteristic is the relationship of moment and angle, ie curve. How to extract it is difficulty.In this paper, the component FE method is used to acquire the stiffness parameters, and the theory and process of extraction are displayed. This method is quite easy to do and efficient. It should be used widely in other passive safety research.Another important technique in modeling is the use of KELVIN element to simulate the reaction of rocker and floor, roof rail and roof. This can improve accuracy of the transform and translation of crash energy.Scheme Optimization and Analysis of the Occupant Restraint System Considering the characteristic of this simulation model , select out several important parameters ,which can be easily modified, they are the longitude and height of seat, the stiffness of the inner door,(protector of pelvis and thorax ). Study the occupant injury trend influenced by the seat position and the stiffness of the inner door.Because of the complicated relation between parameters and each injury, so this paper use the DOE (the design of experiment techniques) method to optimize the occupant restraint system, finally obtain a feasible project to match the parameters, which...
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