某型汽车变速箱的振动噪声分析

针对某型新能源车用两挡变速箱的振动噪声问题,通过NVH试验、理论计算、仿真分析相结合的方法分析引起振动噪声的根源。首先,基于整车NVH主观评价的结果,通过NVH试验采集变速箱振动信号并进行数据处理分析;其次,通过计算变速箱各齿轮副啮合频率及特征阶次,判断各阶噪声的产生位置;最后,使用ANSYS WORKBENCH软件对变速箱壳体进行模态分析进而得出前20阶固有频率,结合试验数据及啮合频率判断产生各阶噪声的共振频率点。基于对变速箱振动噪声的分析,为下一步制定整改措施提供了必要条件。     

车轮踏面的硬化及硬化后的软化处理研究

本文对车轮在运行过程中产生的踏面硬化机理及危害作了简要的阐述,同时对硬化的消除方法进行了深入实验研究,确定了比较理想的工艺方法,取得了满意的结果。     

全寿命周期下高速列车主机厂供应商决策

多属性群决策具有决策指标难以全面评判方案,决策权重难以准确定义,决策方式过于主观三方面难度,造成决策准确性不高。针对高速列车主机厂供应商决策中的以上决策难度,首先基于全寿命周期建立适合主机厂供应商决策的多属性指标体系,并根据各部门职责确定各指标项的决策人员;然后基于此多属性群决策指标体系对各方案进行赋值,并对不同数据类型的值进行二元语义一致性转化,接着在此基础上采用改进的离差最大化方法综合考虑指标在决策体系中的重要度(确定属性权重)及各指标项决策信息的差异(确定可变权重);然后通过计算各方案与理想方案的灰色关联度来进行决策。最后,以某主机厂空气弹簧供应商决策为例,证明了此方法可实现主机厂供应商的合理决策。     

斜齿圆柱齿轮的数字化建模及虚拟装配

以啮合原理为理论基础，研究了斜齿圆柱齿轮的数字化建模方法，提出了斜齿圆柱齿轮虚拟装配的有关概念，建立了斜齿圆柱齿轮虚拟装配的理论体系一解决了斜齿圆柱齿轮的数字化建模与斜齿圆柱齿轮的虚拟装配问题，并通过编程对这一理论进行了验证。     

A feasible timetable generator simulation modelling framework for train scheduling problem

An important problem in management of railway systems is the train scheduling/timetabling problem. This is the problem of determining a timetable for a set of trains that do not violate track capacities and satisfy some operational constraints. In this study, a feasible timetable generator framework for stochastic simulation modelling is developed. The objective is to obtain a feasible train timetable for all trains in the system. The feasible train timetable includes train arrival and departure times at all visited stations and calculated average train travel time. Although this study focuses on train scheduling/timetabling problem, the developed simulation framework can also be used for train rescheduling/dispatching problem if this framework can be fed by real time data. The developed simulation model includes stochastic events, and can easily cope with the disturbances that occur in the railway system.     

The periodicity and robustness in a single-track train scheduling problem

The most important operating problem in any railway industry is to produce robust train timetables with minimum delays. The train scheduling problem is defined as an application of job shop scheduling which is considered to be one of the most interesting research topics. This paper deals with scheduling different types of trains in a single railway track. The authors have focused on the robust and periodic aspects of produced timetables. This paper is also concerned with some applicable constraints, such as the acceleration and deceleration times, station capacity and headway constraints. The periodic timetable for railways is modeled based on the periodic event scheduling problem (PESP). Furthermore, a fuzzy approach is used to reach a tradeoff among the total train delays, the robustness of schedules, and the time interval between departures of trains from the same origins. To solve large-scale problems, a meta-heuristic algorithm based on simulated annealing (SA) is utilized and validated using some numerical examples on a periodic robust train scheduling problem. Finally, a robustness measure is defined in order to assure the effectiveness of the proposed SA to find robust solutions.     

Model scale railcar fire tests

A series of tests has been performed in a model of a typical passenger train compartment (railcar). The tests were carried out on a scale of 1–10. The main purpose of the tests was to investigate if it is possible to calculate the heat release rate for a flashed over train compartment with simple mathematical expressions derived for ordinary compartment fires. The combustion that takes place outside the windows was considered in the study. The parameters that were varied include: the ventilation, the fuel load and the type of interior surface material. In all tests, one door was open and the number of windows varied from all windows closed, to all windows opened. The ignition took place in the corner of the model compartment opposite the door opening.     

等截面斜腿刚构桥的几何布局优化

以应力平方均值最小为优化目标,建立了跨越V形谷的等截面斜腿刚构桥在列车荷载和自重共同作用下的布局静力优化的数学模型,采用直接搜索法进行了设计变量的寻优,结果可供桥梁设计者参考.     

基于安全计算机平台的无线闭塞中心仿真研究*

时速300公里以上的新建铁路线已确定采用CTCS-3级列控系统。为了构建CTCS-3级列控系统仿真测试平台,本文进行了无线闭塞中心仿真研究。研究方法如下：1）针对无线闭塞中心的安全需求,提出安全计算机平台设计方法;2）通过深入分析CTCS-3级列控系统系统需求规范,掌握无线闭塞中心的功能需求;3）进行仿真RBC软件设计与实现。通过在仿真测试平台中实际应用表明,目前的仿真RBC能够完成应有的功能,并满足CTCS-3级列控系统仿真测试平台建设需求。     

提高大学生计算机硬件实践技能的研究与实践

计算机的广泛应用使得计算机硬件实践技能成为大学生知识结构的重要组成部分,而传统教学模式对实践能力的培养有所欠缺,本文就提高大学生硬件实践技能进行研究,并通过教学实践加以检验,探索一条培养应用型人才的新途径。