Forman Jason, Lopez-Valdes Francisco J, Lessley David, Kindig Matthew, Kent Richard, Bostrom Ola
University of Virginia, Center for Applied Biomechanics.
Ann Adv Automot Med. 2009 Oct;53:25-40.
As obesity rates increase, the protection of obese occupants will become increasingly important in vehicle and restraint design. As a first step in this effort, this study seeks to compare the kinematics, dynamics, and injuries of obese post mortem human surrogates (PMHS) to (approximately) 50(th) percentile adult male PMHS in frontal impact sled tests with a force-limiting, pre-tensioning restraint system. Forty-eight km/h, frontal impact sled tests were performed with a sled buck representing the rear seat occupant compartment of a 2004 mid-sized sedan. The restraint system consisted of a 3-point belt with a pretensioner and a progressive force-limiter at the retractor. The test subjects were either obese PMHS or approximately 50(th) percentile adult male PMHS. Instrumentation included accelerometer packages on the spine. Deformation of the subjects' chests were measured using chestbands placed nominally at the superior-inferior locations of the 4(th) and 8(th) ribs. Tension in the restraint system was measured at the upper shoulder belt, lower shoulder belt, and the lap belt. Motion of the head, shoulder, pelvis, and knee were recorded using high-speed video. Two obese PMHS (average mass 137 kg, average stature 186 cm) and three approximately mid-sized male PMHS (average mass 68 kg, average stature 176 cm) were tested. The obese PMHS exhibited significantly greater forward motion of the head and the pelvis compared to the mid-sized PMHS. The obese PMHS also exhibited backwards torso rotation at the time of maximum forward excursion, whereas the mid-sized PMHS did not. The obese PMHS exhibited average maximum chest compressions of approximately 44% (+/- 9% standard deviation) of their initial chest depths, and exhibited 26 g (+/- 2 g) average 3 ms clip maximum chest resultant acceleration. In comparison, the mid-sized PMHS exhibited averages of 29% (+/- 9%) maximum chest compression and 35 g (+/- 4 g) maximum 3 ms clip chest acceleration. The obese PMHS exhibited 7 and 2 rib fractures, with maximum chest AIS scores of 3 and 2. The mid-sized PMHS exhibited 12, 2, and 17 rib fractures, with maximum chest AIS scores of 4, 1, and 4, respectively. This study is the first (to the authors' knowledge) to compare the kinematic, dynamic, and injury behaviors of obese and mid-sized PMHS in frontal impact sled tests with a force-limiting, pretensioning restraint system. The unfavorable kinematics observed with the obese PMHS highlights the difficulty of designing restraint systems to adequately restrain obese occupants, even with currently available advanced restraint technologies.
随着肥胖率的上升，在车辆和约束系统设计中保护肥胖驾乘者将变得愈发重要。作为这项工作的第一步，本研究旨在通过一个带有限力预紧式约束系统的正面碰撞雪橇试验，比较肥胖尸体人类 surrogate（PMHS）与（约）第50百分位成年男性 PMHS 的运动学、动力学和损伤情况。以代表一辆2004年中型轿车后排座椅乘员舱的雪橇台车进行了48公里/小时的正面碰撞雪橇试验。约束系统由一条带有预紧器和卷收器处渐进式限力器的三点式安全带组成。试验对象为肥胖 PMHS 或约第50百分位成年男性 PMHS。测量仪器包括脊柱上的加速度计组件。使用名义上放置在第4和第8肋骨上下位置的胸带来测量受试者胸部的变形。在肩带上部、肩带下部和腰部带上测量约束系统中的张力。使用高速摄像机记录头部、肩部、骨盆和膝盖的运动。测试了两名肥胖 PMHS（平均体重137千克，平均身高186厘米）和三名约为中等身材的男性 PMHS（平均体重68千克，平均身高176厘米）。与中等身材的 PMHS 相比，肥胖 PMHS 的头部和骨盆向前运动明显更大。肥胖 PMHS 在最大向前偏移时还表现出躯干向后旋转，而中等身材的 PMHS 则没有。肥胖 PMHS 的胸部平均最大压缩量约为其初始胸部深度的44%（±9%标准差），平均3毫秒剪辑最大胸部合成加速度为26克（±2克）。相比之下，中等身材的 PMHS 的最大胸部压缩量平均为29%（±9%），最大3毫秒剪辑胸部加速度为35克（±4克）。肥胖 PMHS 出现了7处和2处肋骨骨折，胸部最高 AIS 评分为3分和2分。中等身材的 PMHS 分别出现了12处、2处和17处肋骨骨折，胸部最高 AIS评分分别为4分、1分和4分。据作者所知，本研究首次在带有限力预紧式约束系统的正面碰撞雪橇试验中比较了肥胖和中等身材 PMHS 的运动学、动力学及损伤行为。肥胖 PMHS 观察到的不利运动学情况凸显了设计约束系统以充分约束肥胖驾乘者的困难，即使采用目前可用的先进约束技术也是如此。
