行人-车辆碰撞中六岁儿童下肢损伤分析及预测

Prediction and Analysis of Lower Extremity Injuries of Six-year-old Child Pedestrian in Car-Pedestrian Collision

为揭示汽车-行人碰撞事故中车辆前端结构和速度对儿童行人下肢损伤的差异成因及损伤机理,本研究应用符合我国体征且具有详细解剖学结构的六岁儿童行人损伤仿生模型(TUST IBMs 6YO-P),设置了32组涵盖4类常见车型和8种碰撞速度的汽车-行人碰撞仿真,分析下肢运动学和生物力学响应,采用非线性回归建立预测模型对下肢损伤进行评估。结果表明,碰撞速度对儿童下肢长骨骨折和膝关节损伤有直接影响,汽车前保险杠高度影响股骨的损伤程度和膝关节弯曲角度,扰流板离地高度影响胫、腓骨损伤的严重程度。分析膝关节弯曲角度和韧带断裂数据,得出当膝关节弯曲角度分别超出25.9±0.9°、38.6±0.7°、43.2±0.2°时,撞击侧内侧副韧带(MCL)、前交叉韧带(ACL)、后交叉韧带(PCL)发生断裂,基于碰撞速度和前保险杠高度建立的膝关节弯曲角度预测模型,经反求验证该模型可以有效预测膝关节损伤。综合儿童行人下肢长骨骨折评价参数和所建立的小腿弯矩预测模型,发现碰撞速度高于17.94 km/h将会造成儿童小腿骨折。该研究为行人安全法规制定、行人保护装置研发、AEB系统设计和数字化测评提供科学的参考依据。

In order to investigate in depth the injury mechanisms and the different causes affected by the front-end and the speed on lower extremity injuries of child pedestrian in the car-pedestrian collision,thirty-two car-pedestrian collision simulations are set up using the injury bionic model of six-year-old pedestrian(TUST IBMs 6YO-P)with detailed anatomical structures and four types of common passenger cars given eight crash speeds.The kinematic and biomechanical responses of lower extremity are analyzed.The nonlinear regression prediction models are developed to assess the injuries of lower extremity.The results indicate that the severity of pediatric lower ex‐tremity long bone fractures and knee injuries are directly influenced by the collision speed.The height of the bumper affects the femur injury and knee bending angle,and the height of the spoiler from the ground affects the severity of tibia and fibular injury.By analyzing the data about the knee bending angle and ligament fracture,it is concluded that the medial collateral ligament(MCL),anterior cruciate ligament(ACL)and posterior cruciate ligament(PCL)are fractured with the knee bending angle exceeding 25.9±0.9°,38.6±0.7°and 43.2±0.2°,respectively.Fur‐thermore,the injury prediction model of knee bending angle based on the collision velocity and front bumper height is validated to be effective in predicting the knee joint injury.Combining the evaluation parameters of long bone frac‐ture and predicting model of the bending moment of six-year-old child pedestrian lower extremity,it is concluded that the critical velocity for lower extremity long bone fractures of child pedestrian is 17.94 km/h.These results will provide a scientific reference for the formulation of pedestrian safety regulation,the development of pedestrian pro‐tection devices,the design of AEB system and digital evaluation.