Abstract
Keywords: Pedestrian Safety, Energy Absorber, Sport utility vehicle (SUV).
The recent introduction of pedestrian protection measures in the global automotive market raises questions about the direction of automotive styling. Historically, bumper systems have been expected to protect the vehicle in low speed impact scenarios. However, the significant pedestrian fatalities and incidents in Europe and the rest of the world have changed this expectation. Currently in the European Union vehicles are evaluated on several pedestrian criteria to determine their effectiveness in preventing serious injury, in the case a vehicle strikes a pedestrian. Other global markets are adopting similar standards or currently evaluating the possibility of doing so. One of these current criteria concerns the bumper impact on the knee and lower leg of a pedestrian crossing in front of an oncoming vehicle. This criterion demands that the vehicle´s front end and bumper system is compliant enough to minimize forces and bending moments on the pedestrian´s knee and lower leg to prevent serious injury.
The European Enhanced Vehicle-safety Committee Working Group 17 (EEVC/WG17) pedestrian subsystem test method using a legform impactor has been developed mainly for evaluation of aggressiveness of the front bumper of passenger vehicles. However, in recent years the number of sports utility vehicles (SUV) with a high bumper has been rapidly increasing. Since the bumper height is different between a passenger vehicle and an SUV, thus bumper beam location is marginally above the Knee location. Traditionally, in the automotive industry, energy absorbers are mounted on vehicle bumper beam. Because of high bumper height of SUVs, the large offset between knee location and Energy Absorber front face, results non-uniform support to lower leg, and increases the challenges for a design engineer to meet the lower leg rotation requirements.
So the principal question to be explored is whether there is a reasonable means by which to manage the pedestrian protection criteria for SUVs in an effective and elegant way that is typical of today´s automotive industry. An innovative design solution is proposed, where Energy Absorber is designed to rest on Front End Module (Grill Opening Reinforcement) that supports the lower leg from top and facilitates more controlled energy management, to meet the forces and bending moment requirements. The proposed design solution is evaluated on a generic SUV platform and observed to be meeting phase-II targets with 20% safety margin.