Kinematics of Pediatric Crash Dummies Seated on Vehicle Seats with Realistic Belt Geometry

Objective: A series of sled tests was performed using vehicle seats and Hybrid-III 6-year-old (6YO) and 10YO anthropomorphic test devices (ATDs) to explore possibilities for improving occupant protection for children who are not using belt-positioning booster seats.Methods: Cushion length was varied from production length of 450 mm to a shorter length of 350 mm. Lap belt geometry was set to rear, mid, and forward anchorage locations that span the range of lap belt angles found in vehicles. Six tests each were performed with the 6YO and 10YO Hybrid III ATDs. One additional test was performed using a booster seat with the 6YO. The ATDs were positioned using an updated version of the University of Michigan Transportation Research Institute (UMTRI) seating procedure that positions the ATD hips further forward with longer seat cushions to reflect the effect of cushion length on posture that has been measured with child volunteers. ATD kinematics were evaluated using peak head excursion, peak knee excursion, the difference between peak head and peak knee excursion, and the maximum torso angle.Results: Shortening the seat cushion improved kinematic outcomes, particularly for the 10YO. Lap belt geometry had a greater effect on kinematics with the longer cushion length, with mid or forward belt geometries producing better kinematics than the rearward belt geometry. The worst kinematics for both ATDs occurred with the long cushion length and rearward lap belt geometry. The improvements in kinematics from shorter cushion length or more forward belt geometry are smaller than those provided by a booster seat.Conclusions: The results show potential benefits in occupant protection from shortening cushion length and increasing lap belt angles, particularly for children the size of the 10YO ATD.研究目标：通过搭载汽车座椅与Hybrid-III型6岁（6YO）、10岁拟人测试装置（anthropomorphic test devices, ATDs）开展一系列台车试验，探索提升未使用带位增高座椅儿童乘员防护性能的可行路径。 试验方法：将座椅坐垫长度从量产规格的450毫米调整至350毫米的较短长度；腰部安全带几何参数设置为后置、中置、前置三种锚点位置，覆盖车辆中常见的腰部安全带角度范围。针对6YO与10YO Hybrid-III型拟人测试装置，各开展6组试验；额外增设1组搭配带位增高座椅的6YO测试装置试验。测试装置的坐姿采用密歇根大学交通研究所（University of Michigan Transportation Research Institute, UMTRI）更新版座椅定位规程，该规程通过更长的坐垫将测试装置髋部向前调整，以还原实测得到的坐垫长度对儿童志愿者坐姿的影响。通过峰值头部位移、峰值膝部位移、峰值头膝位移差以及最大躯干角，评估测试装置的运动学响应。 试验结果：缩短坐垫长度可改善运动学表现，对10YO测试装置的提升效果尤为显著。在较长坐垫长度工况下，腰部安全带几何参数对运动学响应的影响更为显著：采用中置或前置锚点的安全带几何参数，相比后置锚点工况可获得更优的运动学表现。两款测试装置最差的运动学表现均出现在长坐垫搭配后置腰部安全带锚点的工况下。相较于使用带位增高座椅带来的防护提升，缩短坐垫长度或前移安全带锚点所带来的运动学性能改善幅度相对较小。 研究结论：结果表明，缩短坐垫长度与增大腰部安全带角度可有效提升儿童乘员防护性能，尤其适配尺寸接近10YO测试装置的儿童群体。