针对12岁儿童的主动式安全气囊的优化

Optimization of Active Safety Airbag for 12-year-old Children

儿童乘员约束系统是汽车尤其是校车中儿童乘员保护的重要手段。本文中针对12岁儿童的主动式安全气囊进行优化。首先,对气囊的上部、中部、下部拉带长度、泄气阀开度、气体质量流率、气囊安装高度和气囊开启压力等7个参数对12岁儿童乘员保护效果的影响进行分析。接着,利用灵敏度分析方法找出主动式安全气囊的3个关键控制参数:上部拉带长度、泄气阀开度和气囊开启压力。最后,采用Latin Hypercube试验设计技术,结合构建综合损伤指标WIC与上部拉带长度、泄气阀开度和气囊开启压力的二次多项式响应面模型,对气囊3个关键参数进行优化。结果表明,当上部拉带长度为0.205 m、气囊开启压力为1.16×10^5 Pa和泄气阀开度为1.8时,12岁儿童乘员的综合损伤指标WIC能达到最小值0.240 5,比初始参数即上部拉带长度为0.235 m、气囊开启压力为1.25×10^5 Pa和泄气阀开度为1时的综合损伤指标WIC降低了24.75%,显著提高了儿童乘员的安全性。

The child occupant restraint system is an important means of protecting the child occupants in vehicles,in particular,school bus.In this paper,the active airbag for 12-year-old child is optimized.Firstly,the effects of seven parameters,i.e.the lengths of the upper,middle and lower straps,the opening percentage of vent valve,the mass flow rate of gas,the installation height and the opening pressure of airbag on the protection results of airbag on 12-year-old child are studied.Then by sensitivity analysis,three key control parameters of active airbag are found to be the length of upper strap,the opening percentage of vent valve and the opening pressure of airbag.Finally,by using the technique of the design of experiment with Latin hypercube sampling,combined with the construction of response surface model with second-order polynomial for the relationship between weighted injury criterion(WIC)and three key parameters of airbag,an optimization is conducted on the three key parameters of airbag.The results show that with an upper strap length of 0.205 m,a vent valve opening percentage of 1.8 and an opening pressure of 1.16×10^5 Pa,the WIC of a 12-year-old child can reach the minimum value of 0.2405.Compared with original airbag parameters,i.e.an upper strap length of 0.235 m,a vent valve opening percentage of 1.0 and an opening pressure of 1.25×10^5 Pa,the optimized airbag achieves a 24.75%reduction in WIC for 12-year-old child.