Influence of Vehicle Front End Design on Pedestrian Lower Leg Performance for SUV Class Vehicle

摘要

Accident statistics shows pedestrian accident fatalities as one of the important concerns globally. In view of this, new test protocols for pedestrian safety have been drafted in regulation as well as in consumer group. Also as per new ENCAP requirements, pedestrian safety assessment is used as one of the four assessment criteria's (Adult protection, child safety, pedestrian safety, safety assist) in deciding the overall vehicle safety. Hence today importance of pedestrian safety is perceived as never before in vehicle development program. Basically pedestrian safety evaluation involves subsystem level (head form, upper leg form and lower leg form) impact tests representing human body parts, at specific region on test vehicle with injury limits to decide the severity of impact. In general these injuries are governed by vehicle styling, vehicle stiffness, hard points clearances from vehicle exterior like bonnet, bumper etc. For head impact, design parameter that mainly control the injury, like bonnet top stiffness design and under bonnet clearances remain valid for both passenger cars as well as for SUV's (Sport Utility Vehicles). Upper leg from impact test is not mandatory to be met in regulation and also difficult to meet in SUV class type vehicles as the location of impact is guided by bonnet leading edge which are quite high in case of SUV's because of vehicle stance. In case of lower leg test, injuries are mainly guided by front styling and bumper to hard point clearance. In SUV's as compared to passenger cars as the ground clearance from the ground is generally higher and vehicle styling is aggressive, controlling the injuries within the limits are quite challenging. This paper specifically discusses important design aspects on controlling the injuries of lower leg form for a SUV type vehicle to meet target requirements. This paper attempt to demonstrate the importance of vehicle front end styling, bumper system design, location of energy absorber, bumper profile, front end stiffness and limitation of bumper to hard point clearance in meeting the lower leg injuries.