Abstract: Regarding the issue of excessive head injury values in a dummy caused by insufficient strength of the seat belt pretensioner lap plate (PLP) bracket during the frontal collision test of a light passenger vehicle model exported to Europe under the ECE R137 regulation, this article studies the impact of bracket strength optimization on dummy injuries. Three sets of seat belt PLP brackets are selected, two of which are strengthened through local thickening and material reinforcement according to the optimized design, while the third maintained the original structure as the initial design. According to the ECE R137 regulation standards, a sliding platform system verification is conducted, with comparative tests performed while keeping other key components of the vehicle restraint system consistent. The center of gravity of the head is successfully reduced from the excessive 82.95g to the standard 73.99g by the continuous composite acceleration of more than 3 ms. The injury criterion values for the head continued to decline; the neck load significantly reduced, with the neck bending moment decreasing by 59.2%, and the chest and thigh injury indicators both met the regulatory requirements with minimal changes. The strength optimization of the PLP bracket can effectively control collision energy, improve the motion posture of the dummy, and significantly enhance the protection performance of the head and neck, providing practical evidence for solving similar restraint system design issues.

Key words: light commercial vehicle; seat belt bracket; structural optimization; occupant protection; crash safety

摘要： 针对某轻客车型在出口欧洲 ECE R137 法规正面碰撞测试中，因安全带预紧器端片 （PLP）支架强度不足导致的假人头部损伤值超标问题，文章研究了支架强度优化对假人损 伤的影响。选取 3 套安全带 PLP 支架，其中两套按优化方案通过局部加厚与材料强化加强了 强度，另一套维持原结构作为初始设计方案。依据 ECE R137 法规标准开展滑台系统验证， 在保持车辆约束系统其他关键部件一致的条件下进行对比测试。支架设计优化后，头部重心 处在持续超过 3 ms 的合成加速度从超标的 82.95g 成功降至达标的 73.99g。头部伤害准则值持 续下降；颈部负载显著降低，其中颈部弯矩降幅达 59.2%；胸部与大腿损伤指标均满足法规 要求且变化微小。PLP 支架的强度优化能有效控制碰撞能量，改善假人运动姿态，显著提升 头部与颈部的保护性能，为解决类似约束系统设计问题提供了实践依据。

关键词: 轻客车型；安全带支架；结构优化；乘员保护；碰撞安全