Design and Analysis of Energy Absorbing Bumper for Pedestrian Lower Leg Protection

• Main Authors: Ching-YiHsiao, 蕭靖宜
• Other Authors: Tsai-Jeon Huang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/36405523116981088639

碩士 === 國立成功大學 === 機械工程學系碩博士班 === 98 === 　　Fatalities related to pedestrian accidents contribute to a large proportion of all traffic accidental deaths. Therefore, the protection of the pedestrian safety becomes more crucial in automotive industry. According to statistics, the lower extremity is the most frequently injured body segment among pedestrian. Lower extremity injuries need to take a long time to rehabilitation, or even cause permanent disability and need to put a lot of medical expenses, therefore, the seriousness can’t be ignored. The main cause for the pedestrian lower leg injury normally is due to the direct impact from the bumper of the vehicle. Therefore, the main aim of this study is to develop engineering countermeasures to lessen the possibility of pedestrian lower extremity injuries based on the bumper design. 　　EEVC (European Enhanced Vehicle-Safety Committee) has developed a pedestrian impact test procedure. These consist of three most commonly injured areas in a pedestrian impact, which are leg, pelvis, and head injuries. The proposed method uses three different impactors to evaluate the pedestrian friendliness of a vehicle. In this study, focus is made on the energy absorbing bumper for pedestrian lower leg protection. For validation, the numerical tests based on EEVC are conduced to evaluate the performance over the complete of the bumper system. 　　The study is departed into three stages. In the first stage, the finite element model of EEVC legform impactor is created and validated against EEVC/WG17 criteria, including static and dynamic tests, and tibia acceleration, knee bending angle and knee shearing displacement of legform impactor are measured. In the second stage, the front structure of car is created, and the numerical test based on EEVC are simulated and analyzed. In the last stage, the five design parameters for the bumper system, stiffness and geometry of energy absorber and bumper beam, are analyzed. Taguchi method is used to study the effect of design parameters. Consequently, the optimal combination of factor-level is attained, and hopefully to reduce the pedestrian’s leg injuries. The study analyzing the best parameter for the bumper system by means of Taguchi method with reducing the pedestrian’s leg injuries and satisfy the EEVC criteria.