Structure Design And Simulation Study On The Pop-up Engine Hood System

Pedestrian protection is an important topic to be solved in the field of vehicleimpact safety. Because of the active hood can protect pedestrian’s head effectively andreduce the casualties in the collision cases immensely, it becames an importantresearch direction of the pedestrian protection fields. Active engine hood system, alsocalled pop-up engine hood system, is designed to provide a space in the engine bay bylifting up the hood before the contact between the pedestrian’s head and the enginehood, thereby avoiding the pedestrian’s head bumping into the hardpoint inside of thehood. It’s a new technology for reducing the severityof a pedestrian’s head in amaximum extent. The active engine hood system is in the preliminary investigationphase and the costs of it used nowadays are too high, so that it only applied into asmall amount significant automotive types.In order to improve these deficiencies, a new pop-up engine hood system adaptedto different automotive types was presented and studied in this paper. The actuatorswere placed near the hood hinges, which located in the rear side of the engine hood, sothat the layout wouldn’t influence the nomal open and shut mode of the engine hood.Compared with the traditional engine hood system, the advantages of this system aresteady, safe, reversible and economical. In addition, it can adapt to differentautomotive types. The multi-rigid body dummy models were developed using Madymosoftware and the vehicle finite element model was founded using Ls-dyna software.The models had been validated according to the test. Then, a vehicle coupling modelwith dummy was presented. This paper set up the parameter analysis model as well asadopting diffierent vehicle velocities, pedestrian velocities, crash positions and percentHuman-Body3D Mathematical Models. The influences of these parameters onpedestrian head dynamic responces and vehicle structural distortion were analysisedcarefully. Meanwhile, the key designed parameters such as the lifted height, executiontime were stablished. In that case, this paper founded the adults’ and children’s headmodels bumping into diffierent types’ vehicle models to compare the head dynamicresponses with the hinges to those without the hinges.The research results indicated that this new type of pop-up engine hood systemcould assure the engine hood’s normal open and shut mode, lift the engine hood rapidlybefore the head contacts to the hood and reset after the head protected process.Inadditions; the simulation results indicated that the key design parameters had influences on the predestrian’s head injury. To some extents, the new active enginehood system could provide effective protection for the children aged more than6yearsold and the adults in frontal impact. As the research results showed, vehicle velocities,crash positions and percent Human-Body3D Mathematical Models could affect headdynamic responses largely.