Kapoor Tanya, Altenhof William, Tot Miroslav, Zhang Wencheng, Howard Andrew, Rasico Jim, Zhu Fuchun, Mizuno Koji
Department of Mechanical, Automotive and Materials Engineering, University of Windsor, Windsor, Ontario, Canada.
Traffic Inj Prev. 2008;9(3):243-55. doi: 10.1080/15389580801975210.
This study focuses on methods to reduce injuries, specifically in the head and neck region, sustained by children seated in forward-facing child restraint system during a frontal vehicle crash. The main objective of this research was to implement load-limiting behavior into the upper tether and lower LATCH anchors of the CRS in order to reduce the neck injury criteria by increasing forward head excursion.
Federal Motor Vehicle Safety Standard 213 outlines that the maximum limit for head excursion of the child dummy should be 720 mm, and the neck injury criteria should be less than 0.33 beyond the first 30 ms of the impact. Working within these limits, a fully deformable finite element model of a child restraint seat incorporating a Hybrid III 3-year-old dummy has been previously developed that has been validated for frontal impacts under CMVSS 208 and FMVSS 213 testing conditions. Observations from this previous work have illustrated that despite the head excursion being significantly less than the proposed limit of 720 mm, values of the neck injury criteria exceeded the protection reference values. Values of the load limits for both upper tether and lower LATCH anchors were calculated based on two approaches, initially based upon neck injury criteria and then an energy-based approach. Three numerical models were developed incorporating a Hybrid III 3-year-old dummy, Q3 child dummy, and a child finite element model. Numerical simulations, utilizing the identical 213 testing conditions, were completed incorporating load-limiting capabilities of the upper tether and lower LATCH anchors.
Evaluation of injury criteria based on the quantitative analysis of the simulations yielded that the implementation of load-limiting behavior in the upper tether and lower LATCH anchors was effective in reducing the head injury criteria by approximately 60 to 70%.
Implementation of load-limiting behavior in the upper tether and lower LATCH anchors of the child restraint system effectively reduces the head and neck injuries sustained by toddlers in a frontal vehicle crash while controlling forward head excursion within the limits as defined by NHTSA.
本研究聚焦于减少儿童在正面车辆碰撞中坐在前向儿童约束系统时所遭受的伤害，特别是头部和颈部区域的伤害。本研究的主要目标是在儿童约束系统的上系绳和下部LATCH锚固件中实施载荷限制行为，以通过增加头部向前偏移来降低颈部损伤标准。
联邦机动车安全标准213规定，儿童假人的头部偏移最大限值应为720毫米，并且在碰撞的前30毫秒之后颈部损伤标准应小于0.33。在这些限制范围内，先前已开发出一个包含Hybrid III 3岁假人的儿童约束座椅的完全可变形有限元模型，该模型已在CMVSS 208和FMVSS 213测试条件下针对正面碰撞进行了验证。先前这项工作的观察结果表明，尽管头部偏移明显小于提议的720毫米限值，但颈部损伤标准值超过了保护参考值。基于两种方法计算了上系绳和下部LATCH锚固件的载荷极限值，最初基于颈部损伤标准，然后是基于能量的方法。开发了三个包含Hybrid III 3岁假人、Q3儿童假人和儿童有限元模型的数值模型。利用相同的213测试条件完成了包含上系绳和下部LATCH锚固件载荷限制能力的数值模拟。
基于模拟的定量分析对损伤标准进行评估得出，在上系绳和下部LATCH锚固件中实施载荷限制行为可有效将头部损伤标准降低约60%至70%。
在儿童约束系统的上系绳和下部LATCH锚固件中实施载荷限制行为可有效减少幼儿在正面车辆碰撞中遭受的头部和颈部损伤，同时将头部向前偏移控制在国家公路交通安全管理局（NHTSA）规定的限值范围内。
