电力机车车轴热处理工艺的研究

分析了EA4T钢的性质特征以及传统调质处理工艺所存在的问题,系统地研究了正火、淬火及回火工艺对材料的组织及性能的影响规律。通过系统的实验,探索出了DJ4型机车车轴的最佳热处理工艺参数。     

和谐HX_D1型大功率交流电力机车电传动系统

详细介绍HXD1型大功率交流电力机车主电路和辅助电路的结构组成、工作原理、技术基础、冗余设计理念以及故障保护机理与实施情况。     

Effects of RE on the Microstructure of Mg-SZn-4Al Magnesium Alloys

The effects of RE on the microstrcture of as-cast Mg-8Zn-4Al magnesium alloys were investigated. The results show that the solidification range of Mg-8Zn-4Al-xRE alloys increases with RE additions. A binary eutectic reaction can arise and produce a new phase （Mg：Al：Zn：RE） and the temperature of phase transformation point of the new phase is 412.85 C. In Mg-8Zn-4Al-1.5RE alloy, a small amount of Mg：Al：Zn：RE phase and ε phases are found besides a（Mg）,φand r phases. Also microstructures of Mg-8Zn-4Al alloys can be refined by addition of 1.5% RE obviously.     

SS4B型电力机车（3）——微机控制系统

ＳＳ４Ｂ型电力机车微机控制系统是在ＳＳ４型００３８号机车和ＳＳ８型机车的基础上研制的，文章介绍了ＳＳ４Ｂ型电力机车微机控制系统的特点、功能和主要参数以及对原有微机控制系统所作的改进。     

Predicting the Dielectric Strength of c-C4F8 and SF6 Gas Mixtures by Monte Carlo Method

An improved Monte Carlo method was used to simulate the motion of electrons in c-C_4F_8 and SF_6 gas mixtures for pulsed townsend discharge. The electron swarm parameters such as effective ionization coefficient, [AKα-] and drift velocity over the E/N range from 280～700 Td(1Td=10-21 V·m2) were calculated by employing a set of cross sections available in literature. From the variation cure of [AKα-] with SF_6 partial pressure p, the limiting field (E/N)_lim of gas mixture at different gas content was determined. It is found that the limiting field of c-C_4F_8 and SF_6 gas mixture is higher than that of pure SF_6 at any SF_6 mixture ratio. Simulation results show excellent agreement with experiment data available in previous literature.     

Robust cascade control for the horizontal motion of a vehicle with single-wheel actuators

The article presents a cascade control for the horizontal motion of a vehicle with single-wheel actuators. The outer control loop for the longitudinal and lateral accelerations and the yaw rate ensures a desired vehicle motion. By a combination of state feedback control and observer-based disturbance feedforward the inner control loop robustly stabilises the rotating and steering motions of the wheels in spite of unknown frictions between tyres and ground. Since the three degrees of freedom of the horizontal motion are affected by eight tyre forces, the vehicle considered is an over-actuated system. Thus additional control objectives can be realised besides the desired motion trajectory as, for example, a maximum in driving safety. The corresponding analytical tyre force allocation also guarantees real-time capability because of its relatively low computational effort. Provided suitable fault detection and isolation are available, the proposed cascade control has the potential of fault-tolerance, because the force allocation is adaptable. Another benefit results from the modular control structure, because it allows a stepwise implementation. Besides, it only requires a small number of measurements for control purposes. These measurements are the rotational speeds and steering angles of the wheels, the longitudinal and lateral acceleration and the yaw rate of the vehicle.     

基于数值模拟的钛合金锯齿状切屑研究

切削加工中切屑成形是一种典型的大变形问题,它涉及到材料非线性、几何非线性以及边界非线性等问题。本文利用DEFORM-2D对钛合金(Ti6Al4V)进行了锯齿状切屑形成过程的有限元模拟,分析了切削过程中的应力场、应变场及温度场,探讨了锯齿状切屑的形成机理,获得了切削参数对锯齿状切屑形态的影响规律,为优化切削参数、提高刀具寿命提供了参考。     

QNX4原理及其启动过程分析

介绍QNX4操作系统的架构和工作原理。并对其启动过程进行了详细分析。     

AWP-2000F型纤维增强桥面粘结防水涂料在南京长江第四大桥的应用

该文首先阐述了桥面防水层的性能要求,并介绍了目前国内某些防水层设置的优缺点。鉴于这些防水层设置方案都存在或大或小的缺陷,长安大学专题组经研究,推出一种纤维增强型防水涂料,并成功应用于南京长江第四大桥。该文介绍了其施工技术方案,可供同行参考。     

一种智能四驱控制的CRUISE仿真及应用

智能四驱是目前SUV车型发展的趋势,如何对该整车模型建模及性能仿真显得尤其重要。文章根据一款SUV车型物理结构及所采用的控制策略进行分析,采用CRUISE软件搭建整车性能仿真模型,并通过试验结果对其动力性经济性进行验证。表明,常用工况中,智能四驱仿真结果与两驱模式下性能基本一致,提供了一种比较行之有效的整车性能匹配的分析方法。