目的 研究AEB对公交车内儿童乘员的颅脑损伤影响。方法 用Prescan软件搭建公交车AEB测试场景,通过仿真得到60km/h初速度下公交车AEB制动工况下的减速度曲线。基于已经验证的公交车模型和具有详细解剖学头部结构的6岁儿童混合有限元模型,选取车内儿童乘员典型的4个乘坐位置,用LS-DYNA软件对公交车有AEB紧急制动和无AEB紧急制动工况下儿童乘员头部损伤进行仿真。以儿童乘员头部HIC15值、大脑灰质处压力、脑组织Von Mises应力及剪切应力等生物力学响应为损伤评价指标,对儿童乘员的颅脑损伤进行分析。结果 各组仿真试验中,位置1和2前方设置挡板时儿童乘员大脑灰质处压力超过其损伤阈值,其余各位置儿童乘员的各项损伤指标均远小于对应的损伤阈值。结论 AEB能有效降低公交车内儿童乘员头部碰撞损伤,公交车内位置3处的儿童容易发生碰撞损伤风险,位置1、2处设置广告牌挡板会增加儿童乘员的颅脑损伤风险。
Objective In order to study the effect of AEB on brain injury of pediatric occupants in buses. Method The bus AEB test scene was developed by using Prescan code. The deceleration curve under the bus AEB braking condition at initial speed of 60km/h is got by simulation method. Based on the validated finite element (FE) bus model and the mixed FE model of a 6-year-old child with detailed anatomical head structure, four typical seating positions in the bus are selected, and the head injury of child passengers seating in these positions with and without automatic emergency braking (AEB) conditions is investigated using simulation method with LS-DYNA code.The craniocerebral injury of child occupants was analyzed by using the HIC15 value of the head of child occupants, the pressure at the gray matter of the brain, the Von Mises stress and shear stress of the brain tissue as the injury evaluation indicators. Results In the simulation of each group, when the baffle is set in front of positions 1 and 2, the pressure at the gray matter of the child occupant"s brain exceeds its injury threshold, and the various injury indicators of the child occupant at other positions are far less than the corresponding injury threshold. Conclusion AEB can effectively reduce the head impact injury severity of child passengers in the bus. The pediatric passenger at position 3 in the bus are prone to higher impact head injury risk. The billboard Setting at positions 1 and 2 in the bus could increase the injury risk of child passengers.