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

ABSTRACTObjectiveA 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.MethodsCushion 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.ResultsShortening 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.ConclusionsThe 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.

摘要
研究目的：本研究采用汽车座椅与Hybrid-III型6岁（6YO）、10岁拟人测试装置（Anthropomorphic Test Devices，ATDs）开展一系列滑车试验，旨在探索提升未使用腰带定位式儿童增高座椅的儿童乘员防护性能的可行方案。
研究方法：将坐垫长度从原厂标准的450毫米调整至350毫米的短长度；设置后、中、前三种锚点位置的腰带几何布局，覆盖车辆中常见的腰带角度范围。针对6YO与10YO的Hybrid-III型ATDs各开展6组试验，额外增设1组使用6YO ATD搭配儿童增高座椅的试验。试验中采用密歇根大学交通研究所（UMTRI）更新版坐姿布置规程，该规程会使ATD髋部在更长坐垫工况下更靠前，以反映坐垫长度对儿童志愿者实测坐姿的影响。通过头部峰值位移、膝部峰值位移、头部与膝部峰值位移之差以及最大躯干角四项指标评估ATD的运动学响应。
研究结果：缩短坐垫长度可优化运动学响应表现，对10YO ATD的改善效果尤为显著。在坐垫长度较长的工况下，腰带几何布局对运动学响应的影响更为显著，采用中置或前置锚点的腰带布局相比后置锚点布局可获得更优的运动学响应。两款ATD运动学响应最差的工况均出现在长坐垫搭配后置腰带锚点的组合下。缩短坐垫长度或调整腰带锚点至更靠前位置所带来的运动学响应优化效果，均弱于使用增高座椅所能实现的优化效果。
研究结论：本研究结果表明，缩短坐垫长度并增大腰带角度可提升儿童乘员防护性能，对于体型匹配10YO ATD的儿童而言，该方案的优势尤为突出。