Validation of Crush Energy Calculation Methods for Use in Accident Reconstructions by Finite Element Analysis

IF 0.7 Q4 TRANSPORTATION SCIENCE & TECHNOLOGY

SAE International Journal of Transportation Safety Pub Date : 2018-10-04 DOI:10.4271/09-06-02-0009

Shusuke Numata, K. Mizuno, D. Ito, D. Okumura, H. Kinoshita

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引用次数: 2

Abstract

The crush energy is a key parameter to determine the delta-V in accident reconstructions. Since an accurate car crush profile can be obtained from 3D scanners, this research aims at validating the methods currently used in calculating crush energy from a crush profile. For this validation, a finite element (FE) car model was analyzed using various types of impact conditions to investigate the theory of energy-based accident reconstruction. Two methods exist to calculate the crush energy: the work based on the barrier force and the work based on force calculated by the vehicle acceleration times the vehicle mass. We show that the crush energy calculated from the barrier force was substantially larger than the internal energy calculated from the FE model. Whereas the crush energy calculated from the vehicle acceleration was comparable to the internal energy of the FE model. In full frontal impact simulations, the energy of approach factor (EAF) has a linear relation with the residual crush, which had been validated in previous experimental studies. In our study using FE analysis, we found that the slope of EAF versus the residual crush was comparable with that of the dynamic crush energy versus the dynamic crush for crashes at 55 km/h. Using this slope and the residual crush from a 55 km/h impact test, the slope and the intercept of the EAF vs. residual crush can be determined using only one crash test. A database of the slopes and the intercepts was made using Japan New Car Assessment Program (JNCAP) tests. In offset impact simulations, the crush energy calculated from the crush profile agreed with the internal energy of the car FE model when at least one front rail was involved. In oblique impacts, the correction factor for crush energy is not necessary within 20 degrees of principal direction of force of the car’s longitudinal axis. Downloaded from SAE International by Duke Univ, Friday, January 11, 2019

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用有限元分析验证用于事故重建的破碎能量计算方法

在事故重建中，粉碎能是确定δ - v的关键参数。由于可以通过3D扫描仪获得精确的汽车挤压剖面，因此本研究旨在验证目前用于从挤压剖面计算挤压能量的方法。为了验证这一点，在不同类型的碰撞条件下，对有限元(FE)汽车模型进行了分析，研究了基于能量的事故重建理论。粉碎能的计算方法有两种:基于屏障力的功和基于车辆加速度乘以车辆质量计算的力的功。我们表明，从屏障力计算的粉碎能大大大于从有限元模型计算的内能。而根据车辆加速度计算的碰撞能与有限元模型的内能相当。在全正面碰撞仿真中，接近因子能量(EAF)与碰撞残余压碎量呈线性关系，这一结论在前人的实验研究中得到了验证。在我们使用有限元分析的研究中，我们发现在55 km/h的碰撞中，EAF与残余碾压的斜率与动态碾压能量与动态碾压的斜率相当。利用这个斜率和55公里/小时碰撞试验的残余碾压，只需要一次碰撞试验就可以确定EAF与残余碾压的斜率和截距。利用日本新车评估程序(JNCAP)测试建立了坡度和截距数据库。在偏置碰撞仿真中，当至少有一根前轨参与时，从碰撞剖面计算的碰撞能与汽车有限元模型的内能一致。在倾斜碰撞中，在汽车纵轴主力方向的20度以内，不需要对粉碎能量进行修正系数。杜克大学从SAE International下载，2019年1月11日星期五

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来源期刊

SAE International Journal of Transportation Safety TRANSPORTATION SCIENCE & TECHNOLOGY-

CiteScore

1.10

自引率

0.00%

发文量