汽车进气系统轰鸣声传递路径分析

为了消除进气系统带来的车内噪声问题,运用传递路径分析方法,源-路径-响应的分析思路,总结了进气系统噪声问题的传递路径,结合某轿车进气系统轰鸣声问题的改进,发现结构传递路径和空气传递路径对该进气轰鸣声均有重要贡献,通过降低空气滤清器安装点橡胶软垫的硬度和加强安装点车身侧支架,可有效降低车内轰鸣声.     

基于车辆加速度数据的互通立交匝道驾驶风险分析

为明确互通立交匝道的运行特性和驾驶风险,在重庆市南山立交和江南立交开展了超过30位被试者的小客车实车驾驶试验,通过Speedbox和Mobileye等车载高精度仪器采集了小客车在4条迂回式匝道上的连续运行数据,包括行驶速度、横向加速度、纵向加速度等,明确了迂回式匝道的车辆运行状态,然后运用表征横、纵向加速度关系的G-G图分析了匝道行驶过程中的驾驶风险,确定了立交匝道不同位置的危险等级及危险驾驶行为的高发路段。研究结果表明：①立交匝道上小客车的横向加速度与速度呈三角形分布,纵向加速度与速度呈椭圆形分布;②小半径曲线匝道上出现危险驾驶行为的比例要高于大半径曲线匝道;③通过统计不同断面的危险驾驶行为点占比,将匝道的危险断面分为低风险、中风险、高风险3个等级;④男性驾驶员在立交匝道上的危险驾驶行为占比要高于女性驾驶员,冒险型驾驶员的危险驾驶行为占比要高于其他驾驶风格的驾驶员;⑤立交匝道的危险高发路段通常位于速度变化剧烈的路段,即入弯减速段和出弯加速段。     

冰击荷载作用下高速车辆-轨道-桥梁系统耦合振动分析

为了探明流冰撞击桥墩对高速车辆-轨道-桥梁耦合系统动力学行为的影响,采用精细化有限元模型模拟了流冰撞击桥墩的过程,计算获得了不同冰排特性下流冰撞击力时程曲线,基于列车-轨道-桥梁动力相互作用理论,以流冰荷载作为外激励,建立了高速车辆-轨道-桥梁-冰击动力学分析模型.以5跨32 m简支梁为例,通过研究不同冰击荷载作用下桥...     

铁路重载货车转向架技术应用探究

铁路重载货车转向架为铁路重载运输提供保障.由于铁路重载货车的重载质量不断增加,运行的速度越来越快速,从而造成了轮轨的损坏,这就需要加强对转向架技术的深入研究.对我国铁路重载货车转向架技术发展的历程进行阐述,详细分析了铁路重载货车转向架技术的应用,并对铁路重载货车转向架的发展趋势进行阐述.     

MPV白车身气密性试验方法及原理研究

当今汽车的舒适性成为了各大汽车生产企业的竞争焦点.白车身作为整车的框架,只有在提升白车身基本性能的情况下才有可能提高整车的舒适性.为此,文章重点研究了MPV白车身的气密性、试验方法和原理,期望通过对MPV气密的研究,为整车NVH性能的提高奠定基础.     

利用故障树方法分析离合器螺栓断裂问题

故障树分析是系统安全性可靠性分析的工具之一,在产品设计阶段,故障树分析可以帮助判明潜在的系统故障模式和灾难性危险因素,发现可靠性和安全性薄弱环节,以便改进设计.在生产、使用阶段,故障树分析可帮助故障诊断,改进使用维修方案,故障树分析也是事故调查的一种有效手段[1].文章采用故障树分析的方法对某车型离合器螺栓断裂故障进行...     

大数据时代天津智慧城市智能交通建设与道路交通发展展望

通过对天津市交通强国建设、京津冀交通一体化及第三届世界智能大会的介绍,从交通运输管理系统、出行服务系统、电子付费系统和交通监控指挥系统智能化升级等方面阐述了天津市逐步进入智能交通应用阶段的情况。在此基础上,论述了5G时代,在“创新、协调、绿色、开放、共享”五大发展理念的引领下,城市道路在道路横断面布置、自行车道设置、共享单车停车点布设、步行交通系统多样化等方面创新设计的思路,展望了在未来万物互联的智能世界中,低碳生态城市和以公共交通为主导的城市综合交通系统的发展前景。     

风积沙的毛细性及其盐胀的室内试验研究

通过毛细水上升高度试验，得出了风积沙在最佳含水量、不同压实度条件下的毛细水上升高度数据；通过室内盐胀试验得到了不同含盐量风积沙的盐胀量，并分析了含盐量及温度与盐胀量的关系。     

Integrated approach to an optimal automotive timing chain system design

Ensuring engine efficiency is a crucial issue for automotive manufacturers. Several manufacturers focus on reducing the time taken to develop and introduce brand new vehicles to the market. Thus, a synergic approach including various simulations is generally adopted to achieve a development schedule and to reduce the cost of physical tests. This study involved proposing a design process that is very useful in the preliminary development stage through effective support from simulations. This type of simulation-based design process is effective in developing timing chain drives; the use of this process, based on results from multiple trials, showed improvements in performance including low friction and vibration, improved durability, and cost-effective part design when compared to conventional processes. This study proposes an integrated approach to the preliminary design of an automotive timing chain system. The approach involves structural and dynamic analyses. The details of the design process are described by using the case of a virtual engine. This study conducted and summarized a dynamic and structural analysis as well as topological optimization to describe a process to obtain optimal results. The results of this study indicated the following improvements in overall performance factors: 12.1 % improvement in transmission error, 10.1 % reduction in chain tension, 46 % reduction in tensioner arm weight, and 11 % reduction in transversal displacement.     

Occupant injury risk analysis at NASS/CDS database

Injury information for vehicle occupants from the body regions of the head, thorax, abdomen, and upper and lower extremities, due to the restraints and interior parts of the vehicle, were extracted from the 2009 ~ 2012 NASS/CDS database. For those cases with high occurrence frequency, a detailed and comprehensive data analysis was performed to find the relationship between the accident, occupant, vehicle, and injury data. A numerical frontal impact sled model with the Hybrid III dummy and the GHBMC human body model was constructed to simulate and identify those injury risks according to NASS/CDS. Among the 5,734 injuries to the aforementioned body regions from frontal crashes are, listed by frequency of occurrence, the lower extremity (27.8 %), upper extremity (21.3 %), thorax (15.1 %), face (10.9 %), spine (8.7 %), head (7.3 %), and abdomen (6.9 %). The main injury sources to the head were the windshield, side structure, and steering wheel. For the thorax and abdomen they were the seat belt and steering wheel. For the lower extremity it was the instrument panel. The main injury patterns for the head were the concussion and the contusion. For the thorax they were vessel laceration and lung contusion. For the abdomen they were laceration and contusion of the organs. For the lower extremity they were bone fracture and ligament rupture. The steering wheel and seat positions were main factors affecting head and thorax injury risks. From the sled impact simulation, high injury risks of the head and thorax were assessed respectively at conditions of steering column tilt down and rear most seat position, which correlated well with the findings from the NASS/CDS data analysis.