共查询到20条相似文献,搜索用时 15 毫秒
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Buses are an integral part of the national transportation system of each country. A rollover event is one of the most important
hazards that concerns the safety of the passengers and the crew in a bus. In the past, it was observed after the accident
that the deforming superstructure seriously threatens the lives of the passengers. Thus, the stiffness of the bus frame is
the first thing that needs to be considered. The unfortunate side of strengthening the bus superstructure is that it usually
causes the bus weight to increase. This paper presents an efficient and robust analysis method with which to design the bus
superstructure for a reduction in occupant injuries from rollover accidents while the weight of the strengthened bus is maintained
at the same level. First, the absorbed energy of the bus frame and its components during a rollover were investigated by using
a LS-DYNA numerical study. The highest energy absorption region, which is the side section of the bus frame, was found and
focused on for the investigation of a means to re-distribute the energy-absorption ability of the side frame component. Then
the thickness parameters that were obtained from the re-distribution of the energy-absorption ability were used in the analysis
to optimize the design. Finally, a prototype of the bus with a reasonable thickness for the window pillars and the side wall
bars, which was based on the optimized parameters, was verified to ensure it satisfied ECE R66. In this paper, an effective
usage of materials and an efficient and robust analysis method were presented to design the bus superstructure. Although the
optimization process for increasing the stiffness is simple, this study improves the upper displacement by 39.9% and the lower
displacement by 49.3% (versus the bus survivor space) while maintaining the bus weight at the existing level. 相似文献
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B. Gepner C. Bojanowski L. Kwasniewski J. Wekezer 《International Journal of Automotive Technology》2014,15(4):581-591
The main objective of the presented study was to compare the effectiveness of two standard test procedures for evaluating bus roof integrity: the dynamic rollover test according to UN-ECE Regulation 66 (ECE-R66), and the quasi-static symmetric roof loading according the Federal Motor Vehicle Safety Standard 220 (FMVSS 220). Both tests were applied to a selected Paratransit Bus. The investigation was carried out primarily using a numerical study backed up by experimental validation tests on components and full scale rollover tests. A sensitivity analysis using LS-OPT? was performed to identify the most important structural components influencing the response of the bus in these two tests. The results obtained from this study show that the final outcome of the crashworthiness assessment of the selected paratransit bus depends on the selection of the evaluation standard. Although the two tests are used for the same purpose of roof integrity evaluation, their results are divergent and may lead to different conclusions. The paper presents a discussion on the effectiveness of both standards in evaluating the rollover crashworthiness. 相似文献
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随着我国汽车碰撞安全性研究的不断发展和国内汽车碰撞试验水平的提高,有关汽车侧面碰撞安全性的法规也开始准备颁布实施。本文主要论述我国开展汽车侧面碰撞研究的重要性,并进行FMVSS214和ECER95侧面碰撞法规的对比分析,介绍FMVSS214和ECER95法规中移动壁变形壁障的几何尺寸及其力学性能要求。最后概述抗侧面碰撞的车身结构设计与改进方法。 相似文献
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通过对比分析ECE R29碰撞法规、瑞典国家碰撞法规和OICA修改意见,参考ECE R66法规中侧翻安全性的试验方法,建立了某款重型货车驾驶室有限元分析模型,并进行计算机模拟侧翻试验,验证其侧翻安全性并找出结构的薄弱环节.根据侧翻仿真分析试验结果提出了结构改进建议,以减轻在侧翻事故中货车驾驶室内乘员所受到的伤害. 相似文献
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Before 2009, rollover in vehicle accidents had not been significantly studied not only because its rate is lower than other types of accidents but also because it had been easy to meet the rollover regulation, the FMVSS 216 Roof Crush Resistance target. The regulation only requires that the strength-to-weight ratio (SWR) be 1.5, i.e., it was acceptable when the roof could withstand a force of only 1.5 times the vehicle??s weight. In other words, rollover is not considered an important safety factor. However, presently, the situation has completely changed. Rollover is now considered a key safety factor. Recently, the number of rollover incidences has been increasing, reaching as much as the number of front, side and rear accidents. Furthermore, the IIHS has begun to require that the roof must withstand a force of 4.0 times the vehicle??s weight, a more severe restriction than FMVSS. To satisfy this requirement, many manufacturers, universities and institutes are studying the topic. This paper focuses on changing the body structure to minimize injury to the occupant when rollover occurs and help rollover safety performance become excellent. This paper draws on a simple analysis that is based on general factors: changes in the material, the addition of welds and additional reinforcements. The best result will be determined, as described by this paper. 相似文献
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A. Gauchía E. Olmeda M. J. L. Boada B. L. Boada V. Díaz 《International Journal of Automotive Technology》2014,15(3):451-461
Engineering bus design requires testing of bus structures prototypes in order to guarantee a certain level of strength and an appropriate static and dynamic behavior of the bus superstructure when exposed to road loads. However, experimental testing of real bus structures is very expensive as it requires expensive resources and space. If testing is done on a scale bus model the previous required expenses are considerably reduced. Therefore, a novel methodology based on dimensional analysis applied to bus structure prediction to evaluate the bus structure static and dynamic performance is proposed. The static performance is evaluated attending to torsion stiffness and the dynamic in terms of the natural vibration frequencies and rollover threshold. A scale bus has been manufactured and dimensionless parameters have been defined in order to project the results obtained in the scale bus model to a larger model. Validation of the proposed methodology has been carried out under experimental and finite element analysis. 相似文献
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Qingguo Wang Wei Zhou Igor Telichev Christine Qiong Wu 《International Journal of Automotive Technology》2018,19(4):705-716
Bus rollover accidents are receiving increasing attention due to the associated high fatality rate. In order to improve the bus structural performance during the rollover collision, it is necessary to investigate how the impact force is transferred within the bus superstructure. This paper introduced a method for studying the load transfer behavior of the bus superstructure during the standard rollover test by using the U * M index. A bus bay section was used as the sample structure to demonstrate the proposed method. The result of the paper reveals that the load transfer analysis based on the U * M index can provide engineers with the insight of the structural issues and the direction to improve the structural performance, which cannot be accomplished through the conventional finite element analysis. 相似文献
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J. H. Seo E. D. Lee J. W. Lee B. K. Han 《International Journal of Automotive Technology》2016,17(4):665-670
This study reports on the effect of vehicle tumble-home (side body inclination) on roof strength. The steep inclination of the side body of a vehicle increases its roof strength. Comprehensive analysis of the impact of high roof strength driven by the steep inclination on dynamic roof strength in rollover is described. Here, we have developed a numerical model using the ADAMS, which is capable of characterizing both of the static and the dynamic roof strength. According to the FMVSS 216 protocol, we achieve the strength to weight ratio (SWR; static roof strength) by applying loading plates to the roof of a vehicle. The Controlled Rollover Impact System (CRIS) allows us to quantitatively characterize the displacements of the top end of A-pillar and B-pillar, thus determining the dynamic roof strength by comparing the results. We demonstrated that the roof intrusion was one of the most critical causes which lead to injuries of occupants fastening seat belts. Our analysis revealed that the increase of the side body inclination of vehicles enhanced the static roof strength whereas it could not reduce the roof displacement (intrusion) in the dynamic rollover. 相似文献
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客车车身侧翻刚度仿真研究 总被引:1,自引:1,他引:0
建立客车骨架的有限元模型,依照ECE R66法规,使用LS-DYNA软件对其进行侧翻仿真分析.在此基础上,分别改变客车顶盖、侧围和前后围的材料,并再次进行仿真计算.对比仿真结果发现.增强前后围刚度可有效提高整车的侧翻刚度. 相似文献
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实车碰撞试验法规的现状和发展趋势 总被引:16,自引:0,他引:16
实车碰撞试验法规主要有美国的FMVSS和欧洲的ECE两大体系,下面碰撞试验法规为FMVSS208、E-CER94,侧面碰撞试验法规为FMVSS214、ECER95,在我国,汽车被动安全性一直是汽车产品较薄弱的环节之一。1999年,我国颁布了第一项汽车技术法规,CMVDR294《关于正面碰撞乘员保护的设计规则》。CMVDR294的颁布表明,我国政府已对汽车的被动安全性有了更全面的评价方法。 相似文献
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Wook-Han Choi Youngmyung Lee Jong-Min Yoon Yong-Ha Han Gyung-Jin Park 《International Journal of Automotive Technology》2018,19(2):291-299
A roof crush test has been utilized to reduce passengers’ injuries from a vehicle rollover. The Federal Motor Vehicle Safety Standards (FMVSS) 216 and the Insurance Institute for Highway Safety (IIHS) perform actual vehicle tests and evaluate the vehicle’s ratings. Nonlinear dynamic response structural optimization can be employed not only for achievement of a high rating but also minimization of the weight. However, the technique needs a huge computation time and cost because many nonlinear dynamic response analyses are required in the time domain. A novel method is proposed for nonlinear dynamic response structural optimization regarding the roof crush test. The process of the proposed method repeats the analysis domain and the design domain until the convergence criteria are satisfied. In the analysis domain, the roof crush test is simulated using a high fidelity model of nonlinear dynamic finite element analysis. In the design domain, a low fidelity model of linear static response structural optimization is utilized with enforced displacements that come from the analysis domain. Correction factors are employed to compensate the differences between a nonlinear dynamic analysis response and a linear static analysis response with enforced displacement. A full-scale vehicle problem is optimized with a constraint on the rigid wall force from the analysis in the design domain. 相似文献
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针对轻型客车上部结构强度在国标中没有具体的试验和评价方法的情况,本文通过分析国内外相关的技术法规,提出一种测试和评价方法,为国内轻型客车此项公告试验方案制定及车身安全性设计提供参考。 相似文献
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本文对工况分析法试验进行了定义,论述了该试验在匹配标定过程中的作用,介绍了该试验中的工况统计分析法和过程分析法在十五工况排放试验,底盘测功机的十五工况油耗和等速油耗试验,试验场整车道路试验,城区道路试验中的应用。 相似文献