Research On Vehicle Sled Test Methodology And Mathematical Simulation Technique Of Side Restraint System

Vehicle sled test method and the mathematical simulation technique of side restraint system are discussed in this doctoral dissertation. The following contents are included:(1) Based on research of the body deceleration pulse in full-scale vehicle frontal impact, the fact that the pulse has dual-level characteristic in lower frequency class filter is discovered. Simplify the deceleration of vehicle body of sled test in frontal impact into the equivalent dual-trapezia pulse. The frontal sled test method based on dual-acceleration level using the equivalent pulse will be proposed. The results of simulation validation have show that it is absolutely feasible to replace the deceleration pulse of the corresponding full-scale vehicle body in frontal impact with equivalent dual-trapezia pulse in sled test. A sled test device based on deceleration using metal sticks as absorbing energy parts has been designed about the method.(2) Based on research of the velocity pulse of door trim in full-scale vehicle side impact, get the characteristic of the velocity pulse of door trim. Simplify the velocity pulse of door trim into the dual-velocity pulse. The side sled test method using the pulse will be proposed. The results of simulation validation have show that it is absolutely feasible to replace the velocity pulse of door trim in full-scale vehicle side impact with simplified dual-velocity pulse in side sled test.(3) Whole discussion about the side airbag modeling technique has not existed so far in China. Side inflatable curtain and simple side airbag that are equipped on Y vehicle and side head-thorax airbag equipped on X vehicle are studied. Describe in detail about modeling process, attention points, problems and resolvents in the process.(4) Whole discussion about the side impact sled test mathematical simulation technique has not existed so far in China. Two mathematical simulation modeling methods of side impact sled test respectively based on the un-deformable door and PSM are discussed, and compare advantages and disadvantages as well as the usage field of two side impact sled model are compared.(5) The influence on the injury values of side dummy in CNCAP because of seat, door trim panel, side airbag and the velocity of door trim panel is studied, using a side impact sled simulation model with door armrest completely corresponding to side impact dummy abdomen. Research shows the friction coefficient of seat and the velocity of door trim panel have much effect on dummy backplate force; the material and shape of door trim influence on all dummy injury estimation index; both dummy rib deformation and VC will be improved obviously after adding side airbag, but some dummy injury index such as pubic force may increase probably; Contact time between dummy and door inner trim, the slope in transition period of two levels on dual-velocity level and the second level affect all dummy injury index especially rib deformation and VC index very much. Considering the time history particularity of T12 moment Mx, contact time difference's influence on the magnitude of Mx is analyzed. Research has show, the shorter two contact time difference of contact time between door rest and dummy abdomen and one between pelvis contact area and pelvis is, the smaller negative Mx is but the greater positive Mx is.Research results in this doctoral dissertation will play an important role in following aspect: improving the development efficiency of vehicle restraint system, lowering development cost, enhancing vehicle side safety and improving vehicle assessment capability in CNCAP side impact test.