Nie Bingbing, Zhou Qing
a State Key Laboratory of Automotive Safety and Energy, Department of Automotive Engineering , Tsinghua University , Beijing , China.
b University of Virginia, Center for Applied Biomechanics , Charlottesville , Virginia.
Traffic Inj Prev. 2016 Oct 2;17(7):712-9. doi: 10.1080/15389588.2016.1143096. Epub 2016 Feb 18.
Pedestrian lower extremity represents the most frequently injured body region in car-to-pedestrian accidents. The European Directive concerning pedestrian safety was established in 2003 for evaluating pedestrian protection performance of car models. However, design changes have not been quantified since then. The goal of this study was to investigate front-end profiles of representative passenger car models and the potential influence on pedestrian lower extremity injury risk.
The front-end styling of sedans and sport utility vehicles (SUV) released from 2008 to 2011 was characterized by the geometrical parameters related to pedestrian safety and compared to representative car models before 2003. The influence of geometrical design change on the resultant risk of injury to pedestrian lower extremity-that is, knee ligament rupture and long bone fracture-was estimated by a previously developed assessment tool assuming identical structural stiffness. Based on response surface generated from simulation results of a human body model (HBM), the tool provided kinematic and kinetic responses of pedestrian lower extremity resulted from a given car's front-end design.
Newer passenger cars exhibited a "flatter" front-end design. The median value of the sedan models provided 87.5 mm less bottom depth, and the SUV models exhibited 94.7 mm less bottom depth. In the lateral impact configuration similar to that in the regulatory test methods, these geometrical changes tend to reduce the injury risk of human knee ligament rupture by 36.6 and 39.6% based on computational approximation. The geometrical changes did not significantly influence the long bone fracture risk.
The present study reviewed the geometrical changes in car front-ends along with regulatory concerns regarding pedestrian safety. A preliminary quantitative benefit of the lower extremity injury reduction was estimated based on these geometrical features. Further investigation is recommended on the structural changes and inclusion of more accident scenarios.
行人下肢是汽车与行人碰撞事故中最常受伤的身体部位。2003年制定了关于行人安全的欧洲指令，用于评估汽车模型的行人保护性能。然而，自那时以来设计变更尚未得到量化。本研究的目的是调查代表性乘用车模型的前端轮廓及其对行人下肢受伤风险的潜在影响。
对2008年至2011年发布的轿车和运动型多用途汽车（SUV）的前端造型，以与行人安全相关的几何参数进行表征，并与2003年之前的代表性汽车模型进行比较。假设结构刚度相同，通过先前开发的评估工具估计几何设计变更对行人下肢受伤（即膝关节韧带断裂和长骨骨折）的综合风险的影响。基于人体模型（HBM）模拟结果生成的响应面，该工具提供了给定汽车前端设计导致的行人下肢的运动学和动力学响应。
新型乘用车呈现出“更扁平”的前端设计。轿车模型的底部深度中位数减少了87.5毫米，SUV模型的底部深度减少了94.7毫米。在与法规测试方法类似的侧面碰撞配置中，基于计算近似，这些几何变化倾向于将人类膝关节韧带断裂的受伤风险降低36.6%和39.6%。几何变化对长骨骨折风险没有显著影响。
本研究回顾了汽车前端的几何变化以及有关行人安全的法规问题。基于这些几何特征估计了降低下肢受伤的初步量化益处。建议对结构变化和纳入更多事故场景进行进一步调查。
