Baker Gretchen, Stockman Isabelle, Bohman Katarina, Jakobsson Lotta, Osvalder Anna-Lisa, Svensson Mats, Wimmerstedt Maria
a Department of Applied Mechanics , Chalmers University of Technology , Göteborg , Sweden.
b Autoliv Research , Vårgårda , Sweden.
Traffic Inj Prev. 2018 Feb 28;19(sup1):S131-S138. doi: 10.1080/15389588.2017.1398401.
To increase the protection of child passengers in crashes preceded by evasive steering, understanding of how children interact with the seat belt in such situations is essential. This study aims to quantify child kinematics and describe child-to-restraint interaction during evasive steering maneuvers.
Eighteen child volunteers (aged 5-10) were seated on the rear seat of a passenger vehicle. A professional driver made repeatable sharp turns at 50 km/h. Children were restrained by the seat belt on a booster cushion (BC) and on an integrated booster cushion (IBC). Kinematics of the nasion and upper sternum were analyzed with video tracking software and shoulder belt (SB) engagement and position were evaluated.
Children moved laterally inboard, and SB-to-body interaction was influenced by booster and stature. Shorter children displayed initial SB positions closer to the neck with less instances of gap between the SB and the lower torso, resulting in more curved belt paths on the IBC. On the BC, shorter children had less of the SB in contact with the torso and straight belt paths were observed throughout steering. Taller children generally had the SB initially mid-shoulder with less instances of gap, resulting in curved belt paths at initial and maximum displacements on both boosters. Children loaded the shoulder belt by axially rotating their torso into the SB more often on the IBC compared to BC. The SB generally stayed on the shoulder, with 89% of slip-off instances occurring for shorter children on the BC. Shorter children on the BC had the largest average inboard nasion displacement (120 mm). Taller children on the BC had the lowest average inboard displacement of the nasion (100 mm). All children initially displaced on average 90 mm inboard with their upper sternum.
Initial SB position on the shoulder and torso differed with booster and stature, which influenced how children engaged with the seat belt during steering. Children with less SB initially in contact with the torso moved laterally behind the belt, resulting in straighter SB paths and outboard motion of the SB on the shoulder (often ending far out or slipped off). When more of the SB was initially in contact with the torso, children tended to engage the SB more, moving with the belt and causing the SB path to become more curved, resulting in less inboard head displacement and less outboard motion of the SB on the shoulder. Enhanced understanding of how evasive steering affects the kinematic response of children provides valuable data for protection of children in real-world situations.
为了增强对在规避转向引发的碰撞中儿童乘客的保护，了解儿童在这种情况下如何与安全带相互作用至关重要。本研究旨在量化儿童运动学，并描述规避转向操作期间儿童与约束装置的相互作用。
18名儿童志愿者（年龄5 - 10岁）坐在乘用车的后排座椅上。一名专业驾驶员以50公里/小时的速度进行可重复的急转弯。儿童使用增高坐垫（BC）和一体式增高坐垫（IBC）上的安全带进行约束。使用视频跟踪软件分析鼻根和上胸骨的运动学，并评估肩带（SB）的接合情况和位置。
儿童向内侧横向移动，SB与身体的相互作用受增高坐垫和身高影响。较矮的儿童初始时SB位置更靠近颈部，SB与下半身之间出现间隙的情况较少，导致IBC上的安全带路径更弯曲。在BC上，较矮的儿童与躯干接触的SB较少，在整个转向过程中观察到的安全带路径是直的。较高的儿童通常初始时SB位于肩部中部，间隙情况较少，导致在两种增高坐垫上初始和最大位移时安全带路径弯曲。与BC相比，儿童在IBC上更频繁地通过将躯干轴向旋转到SB中来加载肩带。SB通常留在肩部，BC上89%的滑脱情况发生在较矮的儿童身上。BC上较矮的儿童鼻根平均内侧位移最大（120毫米）。BC上较高的儿童鼻根平均内侧位移最小（100毫米）。所有儿童上胸骨初始时平均向内侧位移90毫米。
SB在肩部和躯干上的初始位置因增高坐垫和身高而异，这影响了儿童在转向过程中与安全带的接合方式。初始时与躯干接触的SB较少的儿童在安全带后方横向移动，导致安全带路径更直且SB在肩部向外移动（通常最终移得很远或滑落）。当更多的SB初始时与躯干接触时，儿童倾向于更多地与SB接合，随安全带移动并使SB路径变得更弯曲，导致头部内侧位移减少且SB在肩部向外移动减少。对规避转向如何影响儿童运动学反应的深入理解为在实际情况中保护儿童提供了有价值的数据。
