多种儿童坐姿下预充气式安全气囊优化设计

Optimal design of pre-inflatable airbag under multiple child sitting postures

为提升校车正面碰撞中预充气式安全气囊对6岁儿童乘员的保护功效,开展参数分析及优化设计研究,基于台车试验,构建、验证校车仿真模型;搭建校车-预充气式安全气囊耦合模型,面向正常坐姿(NP)、前倾坐姿(OOP 1)与右倾坐姿(OOP 2),探究气囊设计参数对儿童头部伤害指标(HIC)、胸部3 ms合成加速度a 3ms的影响特征。结果表明:当上部拉带长度增加时,气囊上部包形体积增大,HIC明显下降。中部拉带长度决定中下部包形的外部轮廓,安装点高度影响儿童与气囊的接触位置及时刻。NP与OOP 2下,当中部拉带由0.29 m减少至0.26 m时,a 3ms逐渐降低;当安装点高度上升时,HIC随之升高。减小、增大泄气阀的开启压力与开度,有利于头胸部保护。基于改进型第二代非支配排序遗传算法,以加权伤害指标为优化目标,权衡确定主要设计参数的最优配置。具备最优配置的预充气式安全气囊能够高效保护6岁儿童乘员。

In order to improve the protection ability of pre-inflatable airbags for 6-year-old child occupants in the frontal collision of school buses,parameter analysis and design optimization were carried out.Based on the sled test,the simulation model of a school bus was built and verified.The coupling model including a pre-inflatable airbag was established.For the normal sitting posture(NP),forward-leaning sitting posture(OOP 1)and right-leaning sitting posture(OOP 2),the effects of the design parameters on the head injury criterion(HIC),thorax 3 ms resultant acceleration a 3ms were investigated.The results show that when the upper strap length increases,the volume of the airbag upper part increases and HIC decreases significantly.The middle strap length determines the outer contour of the middle and lower parts,and the installation height affects the contact position and contact moment between the child and airbag.For NP and OOP 2,when the middle strap length decreases from 0.29 m to 0.26 m,a 3ms decreases gradually.When the installation height increases,HIC also increases.Decreasing and increasing the opening pressure and degree of the deflation valve can protect the head and thorax.Taking the weighted injury criteria as the optimization target,the improved non-dominated sorting genetic algorithm II is used to optimize the main design parameters.The pre-inflatable airbag with the optimal configuration can reduce child injuries.