The research of reversible pop-up Hood for pedestrian protection

Pedestrian protection has become one of the key points of vehicle design, and the requirements of pedestrian head protection are especially difficult to fulfill. Hood lifting is a new technology which can improve the pedestrian head protection performance of vehicles by lifting up the hood before pedestrian head impact with vehicle, but most of the pop-up hoods available are irreversible, causing high maintenance costs. Therefore a new reversible pop-up hood was designed in this paper. First of all the FE model of the frontal body of the researched car was built and validated with test carried out according to the requirements of Directive 2003/102/EC phase I. Then the simulation analysis of Euro-NCAP head assessment was performed, finding that the head protection performance of the hood areas near windscreen and A-pillars are very poor, structural redesign itself can't improve the score of head protection of those areas efficiently. Therefore a new pop-up hood was designed, which can be lifted upwards and backwards about 0.4 second before the collision between pedestrian and car, to increase the free space beneath the hood and cover the bottom areas of the windscreen and A-pillar. This system also can be reset if the detection system makes false alarms to cut maintenance costs. Simulation results showed that this pop-up hood can efficiently improve the pedestrian head protection performance of the researched car, in accordance with the requirements of Directive 2003/102/EC and Euro-NCAP.