Research On Pedestrian Protection Non-uniform Hood Inner Design

In traffic accident, the proportion of collision accident has been high, and thepedestrian head injury has become the most fatal injuries form. In car to pedestrianimpact accident, head impact to hood parts, which would result in high synthesisacceleration and serious head injuries because of unbefitting absorption structure andnot enough absorption space. As the part directly impact to the pedestrian head, hoodcould sufficiently absorb the headform impact energy in the situation of certainabsorption space with the appropriate design of hood structure, which could reducethe secondary impact velocity between hood and headform, even avoid secondaryimpact and improve vehicle’s pedestrian head protection performance.According to different regulations and test methods’ requirement to headformmodeling and test, a headform modeling method, be suitable for different headforms,was designed in this thesis. In this method, almost all the parts of headform wasreasonably simplified to inerratic geometric sharp, using mathematical method tosolve out feature parameters of each component. According to the GTR requirements,FE model of pedestrian headform impactor has been built by Hypermesh, and thecalibration test based on LS-DYNA was evaluated in this thesis. Additionally,sensitivity analysis has focused on this model’s significant dynamic parameters,leading to some guiding suggestions to both modeling and calibration test ofpedestrian headform impactor.Combined with the geometric model of two car, vehicle-front-structure finiteelement model, which was suitable for the pedestrian protection research, was builtup in the thesis, and simulated with the headform of GTR. The result of simulationagreed with the expected.In order to proceed the study on hood parametric of pedestrian head protectionperformance, vehicle-front-structure was further simplified in the thesis, engine hoodand partial bottom structures were reserved. The result of simulation revealed thissimplification had little influence to simulation results. According to costalia designmethod of hood inner, the relationship between different structures and absorption spaces was discussed and the design method of pedestrian head friendly hood innerwas summarized in this thesis. Using this method, hood inner of one mini-car wasredesigned. The result of simplified model revealed the protection performance ofmost pedestrian head impact area was improved.