Pedestrian Protection in Low Speed Vehicle-Pedestrian Collisions

高速碰撞（40km /h）下的行人保护问题已经得到了广泛的研究。本研究除了研究高速碰撞对行人的保护外，还研究了低速碰撞对行人的保护。利用事故数据，对低速碰撞中行人的损伤类型和严重程度进行了检测。即使在低速碰撞中，行人也可能因头部接触路面或下肢接触保险杠结构而受伤。当行人的头部与路面接触时，受伤的风险很高。建立了一个能够再现行人低速碰撞运动的多体仿真模型。通过文献中的志愿者和尸体试验确定了关节的性能。通过参考文献和车辆抛掷距离的试验结果验证了该模型的正确性。仿真结果表明，在与货车发生碰撞时，行人可以在车辆前方投射出更大的距离并与路面接触。特别是当头部与路面接触时，伤害可能会很严重。在厢式车侧碰撞中，行人表现出躯干绕垂直轴旋转的复杂行为。如果厢式货车的前鼻较短，行人就会被甩到引擎盖上，这样就可以防止头部掉到路面上。低速撞击对下肢的损伤也进行了研究。在冲击速度为20 ~ 40 km/h的条件下，采用汽车和腿式冲击器进行了试验。低速碰撞中下肢受伤的风险对于在高速碰撞速度下表现出相似性能的汽车是不同的。人类有限元分析也应用于行人与这些汽车的碰撞。由于损伤参数远小于胫骨骨折和膝关节韧带断裂的阈值，这些车对行人的伤害风险差异很小。结果表明，在低速车人碰撞中，行人头部接触路面损伤最为严重。少

Pedestrian protection in high velocity collisions (40 km/h) has been investigated in many researches. In the present study, in addition to the pedestrian protection in high velocity impacts, the pedestrian protection at low velocity impacts was examined.Using accident data, the injury types and severities of pedestrian were examined in low velocity collisions. Even in low velocity impacts, pedestrian can be injured due to head contact with road surface or due to lower extremity contact with bumper structures. When the pedestrian head made contact with the road surface, injury risks are high.A multi-body simulation model that can reproduces kinematics of pedestrian in low speed impacts was developed. The joint properties were determined from volunteer and cadaver tests in literatures. This model was validated by test results in references and throwing distance from vehicles. By using this model, it was shown that in a collision with van the pedestrian could be projected in front of vehi … More cle and contact with road surface. Particularly when the head contacts with the road surface, injury can be severe. In the impacts with side of the van type vehicle, the pedestrian showed complex behavior with rotating its torso around vertical axis. When the van has a short front nose, the pedestrian is thrown upon the bonnet and the head falling onto the road surface is likely to be prevented.Injuries to lower extremities in a low velocity impact were also investigated. Experimental tests using cars and legform impactor were carried out with changing impact velocity from 20 to 40 km/h. The injury risks of lower extremities in low velocity collisions were different for cars that show similar performances at high speed impact velocity. The human finite element analyses were also applied for pedestrian collisions with these cars. The difference in injury risks to pedestrian between these cars was small since injury parameters were far smaller than the thresholds of tibia fractures and knee ligament ruptures. From this result, it was demonstrated that the pedestrian head injuries in contact with road surface is most important in low velocity vehicle-pedestrian collisions. Less