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1.
在轿车主动安全性设计中,行人和车相撞的过程中的头部保护是一个国内外研究的重点.越来越严格的汽车安全性法规对行人保护提出了更高的要求.针对基于行人保护的溃缩式的前大灯设计进行了研究,采用有限元分析的方法,对行人头部和前大灯撞击进行了仿真.结论是:溃缩式前大灯能够很好地减少头部的伤害值;并在某国产轿车品牌新车型自主开发中得到了成功的应用.  相似文献   

2.
Pedestrian protection has become an increasingly important consideration in vehicle crash safety. Pedestrian-vehicle crashes cause a significant number of pedestrian fatalities and injuries globally. Computer models are powerful tools for understanding how to reduce the severity of injuries in such crashes. Real-world studies of pedestrians provide an important source of information for evaluating pedestrian model dynamic performance and ability to reconstruct injury-causing events. This study describes the validation process of deformable pedestrian model using published postmortem human subject (PMHS) trajectory and head resultant velocity corridors, and demonstrates its applicability to pedestrian — vehicle impact research. We implemented the deformable pedestrian model using LS-DYNA finite element code. Based on PMHS data, the pedestrian model is used to validate the displacement trajectories of the head, pelvis, knee and foot. The finite element pedestrian model thus obtained can help assess the friendliness of vehicles with pedestrians in traffic crashes and assist in the future development of pedestrian safety technologies. This paper was recommended for publication in revised form by Associate Editor Young Eun Kim Tso-Liang Teng is a Professo r in the Department of mechanical and automation engi-neer ing and the Dean of engineeri ng college at the Da-Yeh Uni versity, Taiwan. He received a BS (1981), MS (1986) and PhD (1994) from the Chung Cheng Institute of Technology. His research intere sts include design of passive safety systems in ve hicles, crash tests simulation, passenger and pedest rian injuries analysis, design of pedestrian protecti on systems.  相似文献   

3.
韩淑洁 《机电工程》2012,29(3):294-296,317
针对钢制发动机罩盖不能满足行人碰撞保护法规要求的问题,对钢制发动机罩盖进行了材料替换和结构设计.在ANSYS中建立了头块和发动机罩盖的有限元模型,通过有限元仿真分析结果与试验结果的对比,证明了有限元建模的可靠性.对新设计的波纹式铝制发动机罩盖和原来的梁式钢制发动机罩盖进行了有限元仿真分析与对比.研究结果表明,新设计的波纹式铝制发动机罩盖可以有效地减小人-车碰撞过程中行人头部伤害值,满足行人碰撞头部保护标准.  相似文献   

4.
This paper presents a dynamically equivalent beam analysis model on pedestrian protection bumper impact instead of a non-linear finite element impact analysis method. Equivalent beam analysis model was developed by substituting the femur and tibia for dynamically equivalent Euler beam. Dynamically equivalent forces of bumper beam, upper stiffener and lower stiffener are found by a finite element analysis results and applied to the Euler beam model of lower legform impactor. This equivalent beam analysis model was used to obtain a bending angle of lower legform impactor by using finite element beam theory. Peak acceleration of the tibia was obtained by developing an approximate acceleration equation. A linear interpolation of non-linear finite element analysis results considering the dimension variation of bumper beam factors affecting the acceleration was used to get an approximate acceleration equation. The accuracy of this simple analysis model was tested by comparing its results with those of the non-linear finite element analysis. Tested bumper beam types were press type beam and roll forming beam used widely in the current car bumpers. The differences of maximum acceleration of the tibia between the two models did not exceed 10% and the bending angle did not exceed 20%. This accuracy is enough to be used in the early stage of bumper beam design to check the bumper pedestrian performance quickly. Use of equivalent beam analysis model is expected to reduce the analysis time with respect to the non-linear finite element analysis significantly.  相似文献   

5.
现阶段我国仍属于人、车混合的交通状况,车辆碰撞事故频繁发生。在车辆与行人碰撞事故中,行人属于弱势群体,加上现阶段车辆缺乏对行人保护的措施,行人伤亡严重。在汽车行人碰撞事故中,行人头部受重伤是造成行人死亡的主要因素;行人腿部受伤是造成行人受重伤的主要因素。基于两款车辆以均分区域法标记试验区域的行人保护头型碰撞测试数据,对其进行分析研究。得到在车辆前期设计时,将吸能空间留得足够大,可减小头型碰撞的伤害值,从而减小对行人的伤害。将理论分析与试验数据相结合,找到影响头型碰撞发动机罩伤害值大小的主要原因为发动机罩距离机舱内部的距离,通过前期造型设计使得发动机罩距离发动机舱内部部件距离足够大,来减小头型碰撞发动机罩的伤害值。  相似文献   

6.
当行人与车辆发生碰撞时,车身最前端的部件将直接与行人下肢腿部发生接触,其设计是满足行人下肢保护要求的关键。然而针对传统要求的基于刚性腿型行人保护车辆前结构设计方法,在应对柔性腿型行人保护要求已呈现明显的局限性。为了提高保险杠结构的柔性腿型保护功能,结合试验设计技术、组合近似建模技术、多目标优化算法和可靠性分析方法,以行人腿部的伤害值最低为优化目标,对车辆前端结构参数进行可靠性优化设计并对优化结果进行试验验证。研究结果表明:优化后的车辆前端结构与原设计相比,行人柔性腿型保护功能得到明显提高,为车辆前端结构的设计与开发提供有效的参考。  相似文献   

7.

The main cause of leg injuries is the bumper during car-pedestrian accidents. Bumper geometry and bumper material have the greatest effect on pedestrian leg injury. The first objective of this study is to evaluate the effects of bumper shape on pedestrian leg injuries. This study uses three bumper shapes on three car models to evaluate the effects of bumper geometry on pedestrian leg injury: A Ford Taurus, Dodge Intrepid, and Dodge-Neon. Then, based on the results of the impact between legform and bumper, this study chooses the best bumper shape that results in the least injury to the pedestrian’s leg. The second objective of this study is to design a new bumper. Using some conclusions regarding the effects of bumper shape on the pedestrian leg injuries, a new pedestrian-friendly bumper was designed. This bumper satisfies EEVC/WG17 safety requirements regarding pedestrian leg injuries. The analyzed models and results obtained could help evaluate pedestrian friendliness of a vehicle and guide the future designing and development of pedestrian friendly vehicle technologies.

  相似文献   

8.
基于行人碰撞保护标准在汽车设计中的要求,将铝材料应用于发动机盖,通过CAE仿真分析了铝制发动机盖和钢制发动机盖对行人碰撞头部伤害标准HIC。对铝制发动机盖的结构提出了优化策略,以达到碰撞时保护行人的目的。  相似文献   

9.
设计了基于52单片机为控制器的简易行人导航系统,利用MPU6050运动处理传感器计算实时三轴加速度、速度,采用QMC5883L弱磁通传感器得到实时航向角,这些采集到的数据经过处理即可获取行人的位置数据、行走方向、行走速度,并通过LCD12864将数据显示出来,实现行人位置及运动状态的实时定位。通过对系统实物进行测试,得到了基本的行人导航所需简易信息参数,验证了本设计的正确性。  相似文献   

10.
人一车碰撞事故中行人的头部同汽车的碰撞往往是造成致命性伤害的关键因素,利用DYNA软件能较好地实现对碰撞过程的仿真,仿真精度能够满足要求并且再现性好。文中介绍了某款车型对头部碰撞的仿真,并对头部的伤害值进行评估,着重分析了造成致命伤害的主要原因,为新车的行人碰撞保护的研究和设计开发作参考。  相似文献   

11.
交通事故中当汽车与行人发生碰撞时,下腿部易受到骨折甚至更严重的伤害.所以行人保护受到越来越多的关注.各大汽车厂商和研究机构也在自身的产品开发中考虑对行人保护的改善.介绍了行人保护法规内容要求和实验要求,并采用仿真方法,建立了行人下腿部撞击器与保险杠碰撞的有限元模型,分析了腿部与保险杠的撞击响应,得到了行人腿部与保险杠相撞时的加速度、弯曲角度、剪切位移等参数,并通过调整保险杠的造型以及保险杠发泡和蒙皮刚度改善车辆前部对下腿部的影响,从而改进对行人腿部碰撞的伤害.  相似文献   

12.
A model was developed for impacts of elastic perfectly plastic spherical particles with impact velocities up to 250 m/s. The model is based on the two master curves, for normalized pressure $\bar{H}$ and projected contact area c 2, which both are functions of the representative strain Λ at maximum impact. The model and its parameters were fitted to finite element results for elastic perfectly plastic and strain rate-independent materials. It was applied to a wide range of materials with different ratio between yield stress and elastic properties, different ball sizes and impact velocities. The impact model predicted the results from finite element method for contact radius, maximum impact depth in both target and ball as well as remaining impact depth in target and ball. The remaining impact depth was determined from elastic spring back with Hertzian and quadratic pressure at maximum impact. The rebound velocity was also estimated by following the load-deformation path during spring back. If the strain rate-compensated yield stress was used for the master curve parameters, then the model predicted the impact results also for the investigated strain rate-dependent materials.  相似文献   

13.
为模拟道路上石子等对汽车塑料燃油箱冲击强度的影响,应用有限元分析软件ABAQUS对冲击能量分别为30、50、70、90 J的尖锤冲击进行了模拟,同时,对塑料燃油箱进行了相应能量的尖锤冲击性能试验,验证模拟结果的可靠性.结果表明:当尖锤冲击能量为30 J时,模拟和试验均未出现失效;当尖锤冲击能量分别为50、70、90 J...  相似文献   

14.
接触损伤和接触变形是交通事故遗留的重要信息,车—人碰撞事故数值再现通常采用标准体形的假人模型和基于椭球体简化的刚体汽车模型,导致车、人接触位置数值仿真结果与真实事故场景存在较大差异,同时,当车速较高时汽车与行人接触部位容易产生过度穿透等问题。以缩放技术为基础,提出基于事故中受害人6大部位体形特征的假人数值模型定制方法。通过材料等效刚度曲线对车身接触部位进行定义,模拟车、人真实接触状态。通过行人与车身等效接触模型的建立,可以提高仿真计算精度,实现计算精度和计算效率的平衡。将上述方法在一起典型的车—人碰撞事故案例中进行应用,仿真结果表明,所得到的事故再现结果精度高、可靠性好,能够满足车辆变形状态下车—人碰撞交通事故过程再现的要求,为交通事故数值再现中的接触问题研究提供了新的思路。  相似文献   

15.
Design of pedestrian friendly vehicle bumper   总被引:2,自引:0,他引:2  
Car-pedestrian accidents take thousands of lives worldwide annually. Therefore, pedestrian protection is an important issue in traffic safety. How to consider a pedestrian friendliness vehicle and then propose pedestrian protection methods are urgent works for minimizing pedestrian injury. For designing a pedestrian friendly vehicle bumper, this study adopts the European Enhanced Vehicle-safety Committee/ Working Group 17 (EEVC/WG17) regulations of legform impactor to bumper tests. Analyzing the pedestrian friendliness of a vehicle bumper by using LS-DYNA is described in detail. Simulation results were analyzed to identify the reasons for the unfriendliness. Furthermore, the analysis of the influence of bumper structure on pedestrian leg was performed and then some guideline was suggested. The analyzed models and results obtained could help evaluate pedestrian friendliness of a vehicle and guide the future development of pedestrian friendly vehicle technologies.  相似文献   

16.
用高能球磨结合热压烧结工艺制备出块状纳米晶体镍,并利用Hopkinson压杆对其进行动态冲击性能试验。结果表明:块状纳米晶体镍具有较高的抗冲击强度,可达到565 MPa,且冲击强度随着应变速率的升高而增大;同时,块状纳米晶体镍的塑性应变硬化率比较小,表现出平稳的塑性流变行为;基于试验结果,预测块状纳米晶体镍的变形机理是由位错滑移和晶界滑移共同控制的。  相似文献   

17.
对网络交换设备进行了二次加固减振设计,同时利用ANSYS仿真分析对产品进行减振辅助设计,以缩短产品开发周期,降低设计成本。通过对网络交换设备进行合理简化,建立了其有限元网格模型。利用ANSYS对网络交换设备进行振动冲击有限元计算,分别获取了网络交换模块印制板在冲击振动下的应力及位移响应曲线。通过ANSYS有限元分析的后处理功能,得到隔振器的最大伸长量以及各部件最大位移量和最大等效应力值。结果表明,隔振器的伸长量在额定范围之内,设备结构的最大等效应力与材料的屈服强度还相差甚远,结构没有产生塑性变形,验证了结构设计的合理性。为网络交换设备的抗振动冲击设计提供了一定的理论参考依据。  相似文献   

18.
以汽车造型特征为研究对象,提取了紧凑型轿车前部造型特征线进行统计分析和参数化研究,通过建立基于特征和特征线的轿车造型特征参数描述模型,赋予造型特征以碰撞安全属性。建立了轿车与行人碰撞的多刚体模型并进行了仿真实验研究,根据仿真结果数据构造二次回归模型分析轿车前部造型特征对行人损伤的影响,并进行了参数优化。研究结果表明:拥有宽大且低矮的保险杠、较高及坡度平缓的发动机罩前缘且发动机罩长度适中的轿车前部造型有利于行人保护。   相似文献   

19.
Surface region plastic deformation of Inconel-718 nickel-base superalloy workpieces was evaluated when machined under orthogonal cutting conditions at various cutting speeds. Plastic deformation analysis was accomplished by determining the residual stress and plastic strain distributions in the surface region. The residual stresses were tensile and maximum near the surface and decreased in magnitude with an increase in depth beneath the machined surface. Similarly, the plastic strains were maximum near the surface and decreased with an increase in depth beneath the machined surface. In addition, a finite element simulation of orthogonal machining was carried out for predicting the residual stress and plastic strain distribution. In general, the trend of the curves predicted by the finite element model was similar to those found experimentally.  相似文献   

20.
Plastic wormgear has many application opportunities in automotive industry because of its low noise and lightweight properties. Three major concerns about plastic wormgear are bending strength, efficiency or friction, and wear. Since standard worm and wormgear designs are developed mainly for metal gears, they are not applicable for the design of plastic wormgear. This paper presented a non-standard design to increase the bending strength of plastic wormgear. By increasing gear contact ratio, the maximum contact stress on the plastic gear tooth was reduced to prevent wear of the plastic wormgear flank. The load, speed, and grease effects on gearbox efficiency and friction coefficient were experimentally studied. While load had a major effect on friction coefficient of grease lubricated plastic wormgear, the speed had much less influence on the friction coefficient of the plastic wormgear. Misalignment of the worm shaft had significant impact on the efficiency of the worm gearbox.  相似文献   

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