车辆偏置碰撞中乘员头部惯性伤降低研究
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摘要
车辆碰撞事故中乘员头部大且持续时间长的转动加速度会造成弥散性脑损伤,NHTSA2018版征求意见稿中提出用BRIC考察这种损伤。统计了美国市场部分车型中BRIC值,评价最差的工况是90km/h OMDB工况,获得优秀评价的比例为33.33%。通过对BRIC值评价优秀车型的分析,认为驾驶员头部在侧气囊和DAB之间稳定滑过是一种较好的保护模式。为验证分析结论,首先建立了OMDB工况下的驾驶员侧模型;研究了DAB、侧气帘、转向管柱对BRIC值的影响;仿真结果表明:a)侧气帘厚度过大过小都不利于BRIC值的降低;b)DAB直径增大有利于增加保护在区域;c)DAB刚度过大过小都不利于BRIC值的降低;d)DAB拉带变长有利于BRIC值的降低;e)转向管柱的溃缩,不利于BRIC值的降低;通过上述方案优化,BRIC值可从0.89降低至0.69,降低幅度可达20%。然后基于仿真优化方案进行了滑台试验,试验结果表明,BRIC值为0.64,与预测值0.69较为接近,预测精度为92.8%。最后基于滑台验证了乘员头部与侧面气帘接触区域平整度对BRIC值的影响,侧面气帘变薄后BRIC值从0.64增加为0.84,影响显著。
Larger and longer rotational acceleration may lead to diffuse brain injury in vehicle collisions. BRIC was used to examine the injury in the NHTSA2018 draft. According to the statistics of BRIC in some American market cars, The worst condition was OMDB, The percentage of excellent evaluations was 33.33%. By analyzing the excellent vehicle, it is considered that the stable sliding of the driver's head between side airbags and DAB is a better protection mode. In order to verify the analysis conclusion, a driver's side model of OMDB was established, and the influence of DAB, CAB and steering column on BRIC was studied. The simulation results show : a) a larger or smaller thickness of SAB is not conductive to the reduction of BRIC; b)Increase the diameter of DAB is beneficial to increase the protection region; c)a larger or smaller stiffness of DAB is not conductive to the reduction of BRIC; d) a longer straps of DAB is conductive to the reduction of BRIC; e) the collapse of the steering column is not conductive to the reduction of BRIC. Through the above optimization scheme, the BRIC can be reduced from 0.89 to 0.69, and the reduction rate can reach 20%. Then, the above optimization scheme was tested, the results show:the BRIC value is 0.64, which is close to the predicted value of 0.69, and the prediction accuracy is 92.8%. Finally, based on the sled test, the effect of the smoothness of the contact area between the head and the side air curtain was verified. BRIC value increased from 0.64 to 0.84 after side air curtain thinning.
Larger and longer rotational acceleration may lead to diffuse brain injury in vehicle collisions. BRIC was used to examine the injury in the NHTSA2018 draft. According to the statistics of BRIC in some American market cars, The worst condition was OMDB, The percentage of excellent evaluations was 33.33%. By analyzing the excellent vehicle, it is considered that the stable sliding of the driver's head between side airbags and DAB is a better protection mode. In order to verify the analysis conclusion, a driver's side model of OMDB was established, and the influence of DAB, CAB and steering column on BRIC was studied. The simulation results show : a) a larger or smaller thickness of SAB is not conductive to the reduction of BRIC; b)Increase the diameter of DAB is beneficial to increase the protection region; c)a larger or smaller stiffness of DAB is not conductive to the reduction of BRIC; d) a longer straps of DAB is conductive to the reduction of BRIC; e) the collapse of the steering column is not conductive to the reduction of BRIC. Through the above optimization scheme, the BRIC can be reduced from 0.89 to 0.69, and the reduction rate can reach 20%. Then, the above optimization scheme was tested, the results show:the BRIC value is 0.64, which is close to the predicted value of 0.69, and the prediction accuracy is 92.8%. Finally, based on the sled test, the effect of the smoothness of the contact area between the head and the side air curtain was verified. BRIC value increased from 0.64 to 0.84 after side air curtain thinning.
引文
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[4]许伟.车辆碰撞事故中头部生物力学响应和损伤机理分析:[湖南大学博士学位论文].长沙:湖南大学机械与运载工程学院,2008,16-17.
[5]Omm aya A K,Yarnell P,Hirsch A E,et al.Scaling of experimental data on cerebral concussion in subhuman primates to concussion threshold froman.In:Proc of 11th Stapp Car Crash Conference.California,USA:Society of Automotive Engineers,1967,73-80.
[6]Abel J M,Gennarelli T A,and Segawa H.Incidence and Severity of cerebral concussion in the rhesus monkey following sagittal plane angular acceleration.In:Proc of 22nd Stapp Car Crash Conference.Ann Arbor,Michigan,USA:Society of Automotive Engineers,1978,35-53.
[7]Versace J.A review of severity index.In:Proc of15th Stapp Car Crash Conference.San Diego:Society of Automotive Engineers,1971,771-786.
[8]Erik G.Takhounts,Matthew J.Craig,Kevin Moorhouse,Joe McFadden.Development of Brain Injury Criteria(BrIC).Stapp Car Crash,Journal,Vol.57(November 2013),pp.243-266.
[2]Takhounts,E.,Eppinger,R.,Campbell,J.,Tannous,R.,Power,E.,Shook,L.,“On the Development of the SIMon Finite Element Head Model.”Stapp Car Crash Journal,Vol.47(October 2003),pp.107-133.
[3]Lee J W,Yoon K H,Kang Y S,et al.Vehicle hood and bumper structure design to mitigate casualties of pedestrian accidents.In:Proc of 19th ESV Conference Washington DC,2005.
[4]许伟.车辆碰撞事故中头部生物力学响应和损伤机理分析:[湖南大学博士学位论文].长沙:湖南大学机械与运载工程学院,2008,16-17.
[5]Omm aya A K,Yarnell P,Hirsch A E,et al.Scaling of experimental data on cerebral concussion in subhuman primates to concussion threshold froman.In:Proc of 11th Stapp Car Crash Conference.California,USA:Society of Automotive Engineers,1967,73-80.
[6]Abel J M,Gennarelli T A,and Segawa H.Incidence and Severity of cerebral concussion in the rhesus monkey following sagittal plane angular acceleration.In:Proc of 22nd Stapp Car Crash Conference.Ann Arbor,Michigan,USA:Society of Automotive Engineers,1978,35-53.
[7]Versace J.A review of severity index.In:Proc of15th Stapp Car Crash Conference.San Diego:Society of Automotive Engineers,1971,771-786.
[8]Erik G.Takhounts,Matthew J.Craig,Kevin Moorhouse,Joe McFadden.Development of Brain Injury Criteria(BrIC).Stapp Car Crash,Journal,Vol.57(November 2013),pp.243-266.