Design of ferrite magnet CFSM to improve speed response of EPS system

This paper deals with the speed response characteristic of the concentrated flux synchronous motor (CFSM) using ferrite magnets for the electric power steering (EPS) system. To analyze the response characteristic of the CFSM, an analytical method using the electromechanical undamped natural frequency and damping ratio based on the transfer function is proposed. By using the method, the speed response according to the variations of the shape of the permanent magnets (PMs) and rotor core is analyzed. It was analyzed under the conditions of the constant volume of the PMs as well as the constant diameter of the rotor. By using the proposed analysis method, the improved model is desgined based on the initial model fulfilling the required specifications. Finally, the torque and speed response characteristics of two motors are simulated through the finite element analysis (FEA) and MATLAB Simulink.     

Dynamic behaviour of a high-speed train hydraulic yaw damper

This paper focuses on revealing the dynamic behaviour of a hydraulic yaw damper under very small excitation conditions. First, the measured yaw damper movement is presented when a train experiences unstable motions. It shows that the yaw damper is characterized by very small harmonic movement between 0.5 and 2?mm. Following this, a simplified physical model of the yaw damper is developed which has the ability to reproduce its dynamic performance in the range of operating conditions, and then suitably validated with experimental results. At last, the dynamic behaviour of the yaw damper under very small amplitudes is investigated by comparing with its static behaviour, and the dynamic stiffness and damping in terms of key parameters are studied. It is concluded that there is a great difference in the damper performance between dynamic and static conditions which is caused by the internal damper flexibility under small amplitudes. The percentage of entrapped air in oil, rubber attachment stiffness, and leakage flow have a great effect on the dynamic behaviour of the yaw damper related to the dynamic stiffness and damping. The effect is even more remarkable for smaller amplitudes regarding the dissolved air in oil. Oil leakage has a greater impact on dynamic damping than dynamic stiffness. The series stiffness of the yaw damper is mainly provided by the spring effect of the oil when the rubber attachment stiffness reached a certain limit, and an additional increase in rubber attachment stiffness becomes useless to further enhance the overall stiffness of the damper.     

地质参数对地基承载力的影响以及土层穿刺评估

地质参数的正确选择对平台安全操作有重要意义。本文针对某自升式海洋平台所处南海海域地质土层,利用数值比较法对砂的内摩擦角以及粘土不排水抗剪强度等地质参数进行研究。通过地质参数前后系数的改变在地基承载力计算结果的体现,比较数值得出结论,并通过所画土层的地基承载力插桩曲线评估该土层发生穿刺危险的可能性。结果表明：采用将砂土内摩擦角降低5°、按实际的土层强度参数进行地基承载力计算和插桩深度预测,计算结果与实际平台操作结果接近以及选取1.5的安全系数计算和评估穿刺危险是可行的。     

供应链物流管理模式分析

供应链管理是全球性竞争的必然产物,通过发展供应链物流,打造第三方平台,可以使航运企业避开恶性竞争.针对中海集运发展供应链物流,从角色定位、资源整合、实施阶段、盈利模式等方面进行阐述,运用案例分析法对蜜柚营销实例进行剖析,指出中海集运发展供应链物流可使企业获得更强的核心竞争力,与战略合作伙伴企业一起实现共赢.     

浅析水尺勘划方法及要点

水尺勘划是船舶施工中比较重要的一个环节,勘划准确性直接关系到船舶空船重量和船舶载重的计算。这里主要对水尺的作用、安装标准、勘划前的准备工作、勘划方法和勘划注意事项等进行了介绍与分析,并对相关勘划方法进行了比较,此水尺勘划方法可以指导相关船厂进行实船水尺勘划。     

随机共振于滚动轴承支撑的转子早期碰摩故障中的应用

通过仿真确认随机共振可以提取强干扰下的微弱信号。将之应用到实验测量的滚动轴承支撑转子早期碰摩故障信号的检测,避开了轴承产生的倍频信号对碰摩信号的干扰,成功检测到了转子早期碰摩的分频信号。说明随机共振对于滚动轴承支撑的转子早期碰摩故障是有效果的。     

舰载导弹库泄压排气理论

分析导弹意外点火后,舰船弹药舱中的气体排出过程。根据能量守恒和质量守恒方程,建立弹药库中导弹意外点火后弹药舱排气过程的微分方程。针对某弹药舱中导弹意外点火情况,计算3种排气面积的弹药舱排气过程,计算结果能够为排气装置的设计提供理论指导和温度速率传感器及压力速率传感器火灾报警阈值的制定提供定量依据。     

基于SOA的船舶电子信息系统仿真

目前,SOA框架和相关技术已相当成熟。其提供一种复杂系统的集成框架,在计算机各个领域中发挥着重要作用。本文研究SOA框架的概念、特点和优势,以及在异构平台上实现不同功能集成与复用的方法,并提出一种利用SOA进行船舶电子信息系统仿真方案。对方案的流程和关键技术进行讨论和阐述,为复杂船舶电子信息系统的集成仿真打下基础。     

快速公交站点类别及步行吸引范围研究

针对目前对BRT站点简单的分类及步行吸引距离的粗泛定义,以济南市1~3 号快速公交作 为研究背景,开展了关于快速公交站点分类方法及各类站点对步行吸引范围的研究。以在19 个快 速公交站点中进行的RP(Revealed Preference Survey)调查及济南ArcGIS 数据库为数据基础,选取 了9 个站点步行吸引距离的影响因素,借助聚类分析法并利用Matlab 工具箱拟合正态分布模型, 最终总结归纳出5 类快速公交站点,并计算得到各类型站点的步行吸引距离。结果表明：终端型 站点的步行吸引距离最长,为1 300m;其次是交通枢纽型站点,为1 100m;城市次中心型与城 市中心型站点步行吸引距离相差不多,平均为750m;一般型站点步行吸引距离最短,约为 630m。不同类型站点的步行吸引距离相差较大,不能以单一经验值解释所有BRT站点,其中城 市次中心型与城市中心型站点步行吸引距离适中,是理想的站点类型。     

再生混凝土与普通混凝土结合面剪应力分析

针对再生混凝土与普通混凝土在结构体系中的协同工作问题,对由混凝土收缩原因引起的再生混凝土与普通混凝土叠合构件变形及结合面剪力问题进行了研究,重点分析结合面上剪应力产生的原因、分布特点、工程影响及其计算公式,并与实际叠合试件的试验数据做了对比分析。结果表明,叠合构件中再生混凝土层的收缩量及收缩稳定期均小于同等条件下自由干缩的再生混凝土,其结合面剪应力分布沿轴线方向随着构件尺寸变化增加明显,构件边缘处的剪应力值最大,从边缘向中部逐渐减小。在实际工程中,可通过合理控制叠合构件的长度和混凝土的配合比等方式,将结合面剪应力控制在允许范围内。