The influence of daily sleep patterns of commercial truck drivers on driving performance

Fatigued and drowsy driving has been found to be a major cause of truck crashes. Lack of sleep is the number one cause of fatigue and drowsiness. However, there are limited data on the sleep patterns (sleep duration, sleep percentage in the duration of non-work period, and the time when sleep occurred) of truck drivers in non-work periods and the impact on driving performance. This paper examined sleep patterns of 96 commercial truck drivers during non-work periods and evaluated the influence these sleep patterns had on truck driving performance. Data were from the Naturalistic Truck Driving Study. Each driver participated in the study for approximately four weeks. A shift was defined as a non-work period followed by a work period. A total of 1397 shifts were identified. Four distinct sleep patterns were identified based on sleep duration, sleep start/end point in a non-work period, and the percentage of sleep with reference to the duration of non-work period. Driving performance was measured by safety-critical events, which included crashes, near-crashes, crash-relevant conflicts, and unintentional lane deviations. Negative binomial regression was used to evaluate the association between the sleep patterns and driving performance, adjusted for driver demographic information. The results showed that the sleep pattern with the highest safety-critical event rate was associated with shorter sleep, sleep in the early stage of a non-work period, and less sleep between 1 a.m. and 5 a.m. This study also found that male drivers, with fewer years of commercial vehicle driving experience and higher body mass index, were associated with deteriorated driving performance and increased driving risk. The results of this study could inform hours-of-service policy-making and benefit safety management in the trucking industry.     

ERP环境下货修成本控制系统的构建

本文在分析南车长江车辆有限公司货修系统出台的背景基础上,对货修的纵向价值链、横向价值链、产品竞争战略等进行探讨,最后结合公司实际搭建了货修的成本控制构架。     

露天矿卡车实时监控调度系统的研制

介绍了一个露天矿卡车实时监控调度系统的研制情况。研制的内容主要包括了系统功能及总体设计、调度数据库设计、车流规划软件设计、实时调度软件设计，着重介绍了系统作业方式设计。该系统成功地进行了室内和现场试验，取得了满意的结果。系统的应用可以减少铲、车的相互等待时间，提高生产效率。     

影响铰接式自卸车操纵稳定性的结构参数分析

铰接式自卸车的工作环境恶劣但载重量较大,对其操纵稳定性具有较高的要求,整车中对此性能的影响因素较多,对影响铰接式自卸车操纵稳定性的结构参数进行分析具有重要意义。稳定性与动态特性是准确描述车辆运行过程中操纵性能的重要特性,根据铰接式自卸车结构特点,为建立准确的整车多自由度操纵动力学模型,用多体系统动力学原理,对整车进行分析并建模。基于多体动力学模型,车辆运行在满载和空载状态时,系统采用角阶跃输入,对各状态参量的瞬态与稳态响应进行分析;分析重要结构参数变化时,对各状态参量的响应情况进行分析,得结构参数对车辆操纵稳定性的不同影响。前轮胎侧偏刚度越小,而后轮的侧偏刚度在一定范围内增大时,整车的操纵稳定性越好,且能够很好的减小车辆转向稳态时的簧载质量侧倾角;车辆悬架刚度对整车状态参量影响较小;轴距越靠前、铰接点越靠前布置越有利于提高操纵稳定性。研究方法和结果为此类车辆设计提供参考。     

160t全地面汽车起重机臂架系统的动态分析

中综述了对汽车起重机臂架系统进行全面动态分析时的计算模型，各工况的分析方法，特别是臂架系统变幅工况的非线性分析，风致涡激振动分析和动态稳定分析，并且介绍了所开发的臂架结构动态分析系统ＥＬＤＹＮＡＲＭ。     

自卸运输车举升机构的优化设计

举升机构对自卸运输车的生产率及性能影响很大，本文在介绍举升机构评价参数的基础上，以油压波动系数为目标函数，对自卸车的举升机构进行了优化设计，优化后的举升机构，有较好的举升力系数曲线和油压特性曲线。     

The dynamic stability of a laboratory model of a truck crane

In the work the dynamic stability of laboratory model of the truck crane is considered. The results in the form of frequency curves for changing the geometry of the system have been presented. Solution of the Mathieu equation enables one to determine the dynamic stability regions of the system. It has been found that, for each of the studied examples, there exists such a rope length for which the critical value of the coefficient a in the Mathieu equation is obtained. That means that for specified geometrical and load conditions, the system may loose its dynamic stability (unless vibration damping is considered).     

国产载重汽车化油器相互代用的可行性研究

将解放CAH101化油器安装到东风汽车发动机上，通过台架试验和道路试验证明，尽管其动力性指标略有下降，但能满足一般情况下汽车的动力性要求；因此在现代战争的紧急状态下，此种应急措施具有一定的现实意义。     

铆接卡车底盘的应力分析

将有限元方法应用于铆接卡车底盘的应力分析。商用有限元软件ANSYS5·3也曾经运用于该课题。制造前测定卡车底盘应力非常重要,为了能够减少底盘框架连接件附近的大量应力,改变了应力集中区域的厚度、连接板厚度及其长度。数值结果显示:可以通过局部增加应力集中区域材料的厚度来减少该区域的应力。如果不能改变材料厚度,增加连接件的长度也是一个很好的替代方法。     

A Genetic Algorithm Evolving Charging Programs in the Ironmaking Blast Furnace

In the ironmaking blast furnace, the distribution of the charged burden plays an important role because it influences the gas distribution in the shaft and the shape and the position of the cohesive zone. Because of enormous mechanical wear and high temperatures and pressure, the possibilities to reliably measure the distribution in real time are severely limited. Even though devices that provide information about the burden surface level have been developed, the high investment and maintenance costs make them economically infeasible in small or medium-size blast furnaces. A simplified first-principles model of the burden distribution forms the basis of the work presented in this article. A method is proposed by which a desired radial ore-to-coke distribution can be achieved by developing charging programs by a genetic algorithm, which was found to be a technique that can tackle this complex and nondifferentiable optimization problem. The algorithm evolves different charging programs subject to practical constraints of the charging (such as maximum skip size and movable armor spans), with the goal to find a charging program that minimizes the differences between the desired and calculated burden distribution. The article describes the method and presents a few illustrative examples on charging programs evolved by it.