从起重机倾翻事故谈门式起重机的稳定性

通过介绍一起门式起重机的倾翻事故及其原因分析,探讨门式起重机稳定性的检验要点。     

提高流动性建材运输车安全性能的方法

为了拌制和运送建筑砂桨和混凝土,目前在俄罗斯使用的有吉尔、玛斯、克拉斯和卡玛斯等汽车底盘改装的混凝土搅拌车、混凝土运输车、砂浆运输车、沥青运输车、石灰桨运输车和液罐车等专用车辆。 这些专用车的试验和运行经验表明,由于纵、横向平面上的动力性增高,导致事故发生率也高。物料流动性是影响这些专用车安全性的重要因素,如底盘车架在横向倾翻卸料时和转向杆在紧急制动时都会产生变形;作业罐内部分装有流动性物料的人机系统(驾驶员-车辆系统)的水平面上自激振动加剧;混凝土搅拌车在前轮爆裂时无法驾驶;车辆在急转弯时会发生横向倾翻,而在沿山坡行驶时包括卸料时也会发生前后倾翻;钢板弹簧刚性不匀称度日益加剧,导致驾驶员的疲劳程度增加等。因此,从对流动性建材运输车使用性能角度出发,首先要求它与货物刚性固定的载货车基本相同,通过遵守必要的行驶规范(限速)和改进结构,从某种程度上消除流动性建材对整车动力性的不良影响。为此,要在实际使用的流动性物料条件下进行实车试验或类同的流态学模拟试验。流动性建材通常有流态的混凝土料、建筑砂浆、加热沥青和重油等。大多数这类混合物料是非牛顿力当量性流体。在连续体内应力很低的     

客车整车制动稳定性硬件在环仿真研究

针对客车在转弯或有侧向干扰时的制动稳定性分析中存在气制动系统建模非线性误差和实车实验模拟困难、危险性大等问题,采用硬件在环仿真测试技术设计一套客车整车制动稳定性仿真测试系统。首先搭建客车气制动系统的硬件实物平台,运用Matlab/Smulink建立转弯时的车体、轮胎、制动器的仿真模型,采用Matlab/x PC的实时数据采集技术对客车制动时的制动气室输出力进行数据采集,并实时反馈至车辆动力学仿真模型。系统对客车转弯时及有侧向力影响下的制动稳定性进行测试分析,试验结果表明:系统采样频率为1 k Hz,输出力分辨率为10 N,可以直观地显示车辆的制动过程及结果,能够很好地对客车制动稳定性能进行测试分析,为国内客车整车制动性能的提高提供一个良好的研究平台。     

承钢热修钢包倾翻系统的电气控制与应用

目前国内越来越多的炼钢厂钢水罐热修工序均采用配置钢水罐倾翻装置的方式来代替传统的钢水罐热修坑。钢水罐倾翻装置主要用来将钢水罐（带有内衬及残渣的空罐）倾翻至一定角度（0°、90°、180°）,进行热修作业。实践证明钢水罐倾翻装置的使用大大提高了钢包热修效率,节省了行车占用时间。     

可倾瓦滑动轴承系统线性稳定性分析

提出可倾瓦轴承系统解析模型并对其进行线性稳定性分析。采用Newton-Raphson和pad assembly这两种方法,可获得系统完整的动力特性系数。基于这些动力特性系数,建立系统的运动微分方程并进行复特征值分析,易求得用来检验系统稳定性的轴瓦临界质量和系统阻尼比。结果表明:预负荷、转速及支点位置均对可倾瓦轴承系统的稳定性有着较大的影响,合理选取这些参数有助于提高系统的稳定临界值。     

自卸汽车后板锁紧机构剖析

自卸汽车是指通过液压或机械举升而自行卸载货物的车辆。由于车厢需要倾翻一定角度卸料,车厢后板通过顶端两侧转动臂绕销轴能自动打开。运输过程中,车厢后板下部需要锁紧机构将后板与厢体锁紧成一体,防止货物抛洒,倾泻货物时,锁紧机构需安全打开,后板及时开启卸料,防止车辆倾翻,后板锁紧机构的安全有效尤为重要。该文介绍了几种自卸汽车后板锁紧机构的结构形式及特点,为自卸车设计提供参考,减少设计中问题的发生,提高了自卸车车厢后板启闭的安全性、方便性、实用性,可大大减少使用维修费,降低安全隐患。     

JF型砼搅拌机的振动特性与减振方法

对双锥倾翻自落式砼搅拌机在搅拌过程、倾翻过程和复位过程中振动的特征、原因及减振措施分别作了较详细的叙述。搅拌过程中的振动是个正弦函数,减振方法主要是使转速避开共振区及采用隔振材料;倾翻过程中的振动是由砼重心的变化及倾翻惯性力引起的,减振关键在于选择合适的支点,另可用背压贮气筒来减振;复位过程中振动是由复位惯性引起的,可通过控制电磁阀的启闭程度来减振。除上述措施外采用液压倾翻机构、独立的搅拌机平台或砼搅拌平台也是行之有效的减振措施。     

轨道车辆动态限界测试系统设计

针对传统轨道车辆限界测试不能实时、连续、快速获得车辆限界的不足,提出一种车辆限界自动化测试系统。该系统根据车辆限界标准及测试要求,结合车辆结构和车辆相对于轨道位置变化的特点,通过在车体及转向架上布置测量传感器,测量车辆相对于轨道的位移和偏转角度,然后提出一种算法对传感器输出数据进行处理,完成轨道车辆的动态轮廓线的实时计算,并在车辆行驶过程中叠加生成车辆最大动态轮廓边界。同时测试过程中通过车辆的动态轮廓与标准限界的实时比较,实现对车辆限界的监测与校核。实车对比试验表明,传统方法测试的车辆轮廓与该测试系统测试结果误差范围在1%以内,该测试系统能够准确测量车辆轮廓线,并在车辆运行过程中实现车辆限界的在线、实时、连续测试。     

国内标准和ASTM标准柜类稳定性比对分析

针对近期宜家北美柜类产品召回事件,本文对国内标准GB/T10357.4-2013和ASTM F2057-14标准中关于柜类稳定性的关键技术进行了比较,前者侧重于柜子正常使用中,抽屉负载拉出后的稳定性;后者侧重于极端情况下,儿童攀爬引起的柜体稳定性。后者的要求比前者严苛。比较试验结果显示,按照ASTM F2057-14试验时,柜类产品发生倾翻的可能性更大。     

倾翻工作台式铝包清理机结构及原理

通过阐述目前电解铝厂转运液态铝的铝包的清理状况,说明倾翻工作台式铝包清理机在电解铝生产过程中的重大意义,介绍倾翻工作台式铝包清理机的主要结构和工作原理。     

Thoracic injuries to contained and restrained occupants in single-vehicle pure rollover crashes

Around one in three contained and restrained seriously injured occupants in single-vehicle pure rollover crashes receive a serious injury to the thorax. With dynamic rollover test protocols currently under development, there is a need to understand the nature and cause of serious thoracic injuries incurred in rollover events. This will allow decisions to be made with regards to adoption of a suitable crash test dummy and appropriate thoracic injury criteria in such protocols. Valid rollover occupant protection test protocols will lead to vehicle improvements that will reduce the high trauma burden of vehicle rollover crashes. This paper presents an analysis of contained and restrained occupants involved in single-vehicle pure rollover crashes that occurred in the United States between 2000 and 2009 (inclusive). Serious thoracic injury typology and causality are determined. A logistic regression model is developed to determine associations between the incidence of serious thoracic injury and the human, vehicle and environmental characteristics of the crashes. Recommendations are made with regards to the appropriate assessment of potential thoracic injury in dynamic rollover occupant protection crash test protocols.     

重型车侧翻特性理论分析及防侧翻支架设计简

 为研究重型车侧翻特性,建立准静态侧翻的系统理论计算模型,导出其侧倾力臂h和整车等效轮距B的理论计算公式,分析了各主要参数的影响,并以某重载搅拌车为例,计算了其准静态侧翻阀值,同时针对该车极限稳态回转试验,进行了防侧翻支架设计,并利用稳态回转试验,对理论计算模型及支架结构进行验证.试验结果表明：理论计算所得的准静态侧翻阀值与试验结果相吻合,所设计的防侧翻支架可以准确有效地进行车辆侧翻的预警和保护,达到了预期的设计目标.     

Cervical and thoracic spine injury from interactions with vehicle roofs in pure rollover crashes

Around one third of serious injuries sustained by belted, non-ejected occupants in pure rollover crashes occur to the spine. Dynamic rollover crash test methodologies have been established in Australia and the United States, with the aims of understanding injury potential in rollovers and establishing the basis of an occupant rollover protection crashworthiness test protocol that could be adopted by consumer new car assessment programmes and government regulators internationally. However, for any proposed test protocol to be effective in reducing the high trauma burden resulting from rollover crashes, appropriate anthropomorphic devices that replicate real-world injury mechanisms and biomechanical loads are required. To date, consensus regarding the combination of anthropomorphic device and neck injury criteria for rollover crash tests has not been reached. The aim of the present study is to provide new information pertaining to the nature and mechanisms of spine injury in pure rollover crashes, and to assist in the assessment of spine injury potential in rollover crash tests. Real-world spine injury cases that resulted from pure rollover crashes in the United States between 2000 and 2009 are identified, and compared with cadaver experiments under vertical load by other authors. The analysis is restricted to contained, restrained occupants that were injured from contact with the vehicle roof structure during a pure rollover, and the role of roof intrusion in creating potential for spine injury is assessed. Recommendations for assessing the potential for spine injury in rollover occupant protection crash test protocols are made.     

受饱和约束的车辆转向非线性鲁棒模糊分布控制

针对极限状态下车辆转向非线性和执行器饱和问题,研究主动前轮转向(active front steering, AFS)和直接横摆力矩控制(direct yaw-moment control, DYC)对横摆-侧倾稳定的集成控制。采用Takagi-Sugeon(T-S)方法建立车辆3自由度横摆侧倾模型,结合模糊观测器实时获取模型动态参数。为准确反映车辆转向稳态过程,在T-S框架下建立改进横摆理想参考模型。考虑到极限转向对前轮侧偏特性的影响,构建T-S框架下主动前轮输入的动态饱和阈值。引入松弛因子提高AFS和DYC的执行器利用率,将反馈输入的饱和影响作为有界扰动进行控制。基于分布补偿结构设计状态反馈模糊分布控制器(parallel distributed compensation-TS,PDC-TS),采用范数有界的侧翻稳定阈作为侧倾性能约束,将车辆横摆-侧倾稳定性的H;性能转换为线性矩阵不等式(linear matrix inequalities, LMIs)凸优化问题。最后联合Trucksim-MATLAB/Labview软件进行控制仿真和硬件在环验证,结果表明,PDC-TS方法对强非线性转向过程的控制更加准确,执行器能力利用更充分,并在输入饱和约束下保持控制稳定性。     

受饱和约束的车辆转向非线性鲁棒模糊分布控制

针对极限状态下车辆转向非线性和执行器饱和问题,研究主动前轮转向(active front steering, AFS)和直接横摆力矩控制(direct yaw-moment control, DYC)对横摆-侧倾稳定的集成控制。采用Takagi-Sugeon(T-S)方法建立车辆3自由度横摆侧倾模型,结合模糊观测器实时获取模型动态参数。为准确反映车辆转向稳态过程,在T-S框架下建立改进横摆理想参考模型。考虑到极限转向对前轮侧偏特性的影响,构建T-S框架下主动前轮输入的动态饱和阈值。引入松弛因子提高AFS和DYC的执行器利用率,将反馈输入的饱和影响作为有界扰动进行控制。基于分布补偿结构设计状态反馈模糊分布控制器(parallel distributed compensation-TS,PDC-TS),采用范数有界的侧翻稳定阈作为侧倾性能约束,将车辆横摆-侧倾稳定性的H;性能转换为线性矩阵不等式(linear matrix inequalities, LMIs)凸优化问题。最后联合Trucksim-MATLAB/Labview软件进行控制仿真和硬件在环验证,结果表明,PDC-TS方法对强非线性转向过程的控制更加准确,执行器能力利用更充分,并在输入饱和约束下保持控制稳定性。     

Field relevance of a suite of rollover tests to real-world crashes and injuries

The objective of this study was to assess the distribution of rollover accidents occurring in the field and to compare the vehicle kinematics in the predominant field crash modes with available laboratory tests. For this purpose, US accident data were analyzed to identify types and circumstances for vehicle rollovers. Rollovers were most commonly induced when the lateral motion of the vehicle was suddenly slowed or stopped. This type of rollover mechanism is referred to as "trip-over". Trip-overs accounted for 57% of passenger car and 51% of light truck vehicle (LTV) rollovers. More than 90% of trip-overs were initiated by ground contact. Fall-overs were the second most common rollover type, accounting for 13% of passenger car and 15% of LTV rollovers. Bounce-overs only accounted for 8% of both passenger car and LTV rollovers.The FMVSS 208 dolly and the ADAC corkscrew rollover tests are well-known laboratory tests, but do not simulate many of the real-world rollovers. Three additional tests have been devised to more fully address the field relevant conditions identified in this study. To do so, assumptions were made and adding the new laboratory tests (soil-trip, curb-trip and ditch fall-over) increases representativeness to 83% of passenger car and 75% of LTV rollovers reported in the field. Accident data were also used to identify injuries in belted drivers so the information could later be used to better understand occupant kinematics in various roll conditions. The injury distribution for belted/non-ejected drivers was assessed for trip-over, fall-over and bounce-over accidents. Serious injuries (AIS 3+) were most common to the head and thorax, in particular for bounce-overs. Head injuries occurred from contact with the roof, pillar and the interior, while thoracic injuries resulted from contact with the interior and steering wheel assembly. Field data are useful in the development of laboratory test conditions for rollovers as it provides insights on the significance of various rollover types, understanding of injury biomechanics, guidance for future testing and inputs for mathematical modeling.     

Relative risk of spinal cord injury in road crashes involving seriously injured occupants of light passenger vehicles

Road crashes involving occupants of light passenger vehicles are the leading cause of traumatic spinal cord injury (SCI). Confirming the results of an earlier study, this study showed that: in single vehicle car crashes in the country, the odds of SCI were nearly five times higher (4.7) for occupants of non-sedan type light passenger vehicles compared with sedans; in single vehicle rollover crashes in the country, the odds of SCI were nearly three times higher (2.8) in non-sedans compared with sedans; the odds of SCI were nearly five times higher (4.8) for sports utility vehicles (SUVs) compared with sedans. When the data from the earlier study was included in order to increase statistical power, it was found that when compared to sedans that did not roll, occupants of all types of light passenger vehicles had a statistically significant substantially higher likelihood of SCI when involved in rollover (sedans 7.5 times, SUVs 5.9 times and others 8.4 times). In addition, SUVs had a higher likelihood of SCI even when not involved in rollover (5.4 times). Vehicle designers and regulators need to give more attention to the prevention of vehicle rollover and the means to improve occupant protection in the event of rollover. This study should be extended nationally to gain a larger case series so that the SCI risk of particular vehicle configurations, considering other crash factors, can be more precisely quantified and characteristics for low occurrence of SCI identified.     

Overall injury risk to different drivers: combining exposure,frequency, and severity models

Traffic crash risk assessments should incorporate appropriate exposure data. However, existing US nationwide crash data sets, the NASS General Estimates System (GES) and the Fatality Analysis Reporting System (FARS), do not contain information on driver or vehicle exposure. In order to obtain appropriate exposure data, this work estimates vehicle miles driven (VMD) by different drivers using the Nationwide Personal Transportation Survey (NPTS). These results are combined with annual crash rates and injury severity information from the GES for a comprehensive assessment of overall risk to different drivers across vehicle classes.Data are distinguished by driver age, gender, vehicle type, crash type (rollover versus non-rollover), and injury severity. After correcting for drivers' crash exposure, results indicate that young drivers are far more crash prone than other drivers (per VMD) and that drivers of sports utility vehicles (SUVs) and pickups (PUs) are more likely to be involved in rollover crashes than those driving passenger cars. Although, the results suggest that drivers of SUVs are generally much less crash prone than drivers of passenger cars, the rollover propensity of SUVs and the severity of that crash type offset many of the incident benefits for SUV drivers.     

Micromachined Angular Rate Sensors for Automotive Applications

Micromachined angular rate sensors are key elements in several automotive systems, thus enabling highly sophisticated applications like rollover detection and mitigation, navigation systems, electronic stability program, and other future vehicle stabilizing and dynamics control systems. New automotive systems are demanding higher accuracy, better signal-to-noise ratio, higher robustness and insensitivity against external perturbations, better system availability and reliability, as well as easy application of the gyros. This paper is presenting the recent development, now the third generation, of micromachined angular rate sensors at Robert Bosch GmbH. Mass production was started in spring 2005. These surface micromachined gyroscopes exhibit outstanding performance compared to similar designs, especially in term of resolution, noise, and insensitivity against external perturbations     

Rollover risk of cars and light trucks after accounting for driver and environmental factors

Characteristics of the driver, roadway environment, and vehicle were associated with the likelihood of rollover occurrence in more than 14000 single-vehicle fatal and 78000 single-vehicle injury crashes during 1995-98. Rollovers were more likely in crashes involving young drivers or occurring on rural curves. After accounting for the effects of driver age and gender, roadway alignment and surface condition, and whether or not the crash occurred in a rural area, light trucks were still twice as likely as cars to experience rollovers. Some light truck models were much more likely than others to experience rollovers. However, while physical differences (e.g. center of gravity height) could explain some of this variability, other factors affecting vehicle stability may be evident only after dynamic testing.