日本铁道车辆下部噪声源分布的试验研究

铁道车辆下部噪声主要由滚动噪声、空气动力噪声和机器噪声组成。采用声强测试法确定了新干线和既有线车辆滚动噪声的主要噪声源,并初步分析了两者噪声源分布不同的原因。     

论中小投资者权益保护

中国股市的低迷引发了资本市场情形的恶化。对此问题的解决也越来越紧迫。本文试图从投资者保护机制方面进行探讨。在对股市投资的“异象”进行分析的基础上,指出熊市"漫漫"的内在机理,并提出了相应的保护资本投资者的建议。     

CATIA二次开发在船舶建模与评估中的应用

为提高CATIA在船舶建模评估应用中的效率与精度,使用VB编程语言对CATIA进行二次开发,建立界面,不仅可方便地输入舵参数,快速创建舵和舵踵曲面,而且可设定吃水高度、海水密度、船壳厚度等,以统计主尺度、船形系数和尺度比等多种船体主要要素并自动导出,大幅提高多方案建模与评估的工作效率。给出程序思想和关键程序代码,对相关软件开发具有参考作用。     

船舶轴舵系安装设备的虚拟设计与装配

以船舶轴舵系安装设备为例,使用SolidWorks软件设计建立轴舵系安装设备的三维实体模型,研究轴舵系安装设备的安装过程和安装工艺,并对轴舵系安装设备的干涉检查及装配约束进行仿真分析,以验证轴舵系安装设备在设计及安装工艺方面的准确性和适用性,对提高造船设备产品质量、降低产品设计误差、缩短生产周期、优化装配流程具有重要意义。     

Fatigue damage prediction of ship rudders under vortex-induced vibration using orthonormal modal FSI analysis

Recently, the fatigue failure of ship rudders owing to vortex-induced vibration has increased as commercial ships become faster and larger. However, previous methods are inappropriate for fatigue failure prevention owing to the lack of fluid–structure interaction considerations. This study aims to develop a fatigue damage prediction method that can be applied at the design stage to prevent fatigue failure of ship rudders under vortex-induced vibration. The developed prediction method employed the fluid–structure interaction (FSI) method to properly consider the fluid–structure interaction and implemented orthonormal mode shapes to reflect the complex geometry and boundary conditions of the ship rudders. For validation, vortex-induced vibration of the hydrofoil model was obtained using the developed method, and the prediction results matched well with the experimental results. Then, the fatigue damage of the ship rudder model under vortex-induced vibration was predicted using the developed method, and their characteristics are discussed. The stress distribution obtained using the developed method matched well with the geometrical characteristics of the ship rudders. The potential for fatigue failure due to the resonance of vortex-induced vibration was expected by comparing the stress distributions for various flow velocities to the S–N curves provided by the DNV classification.     

舵装置的优化设计

为使"渤船"第五代苏伊士船型具有良好的操纵性能,提高市场竞争力,对船体设备舵装置设计方案和实际选型计算进行研究和讨论。对多个舵选型公式进行对比,在完成船型研发任务的同时形成一套合理的舵系设计流程:参考同类型先进船型信息,结合规范要求和水池方意见,确定舵装置设计参数。该设计流程可在较大程度上提高工作效率和质量,为快速研发新船型提供支持。     

Analysis on maneuvering motion characteristics of submarine under static moment in vertical plane北大核心CSCD

[Objectives]Aiming at the problem of poor depth-changing ability of the stern rudder of submarine at low speed, and the problem of reversing the movement trend is difficult when the stern rudder is stuck and encountering abrupt changes of seawater density in the vertical steering maneuver. This paper conducts the mechanism research of static moment maneuver. [Methods]First, it is proved through theoretical analysis that the static moment maneuver can eliminate the reversed velocity phenomenon of the stern rudder. Then, the surfacing process under the static moment maneuver and the rudder hydrodynamic control is numerically simulated. [Results]The simulation results show that the static moment maneuver can make the submarine maintain good vertical plane maneuverability at low speed, eliminate the reversed velocity phenomenon of the stern rudder, and avoid excessive trim angle of the submarine at high speed. At the same time, the recovery effect of the two emergency situations of rudder jamming and falling deep has been improved. [Conclusions]The static moment maneuver is beneficial to the maneuverability and safety of the submarine. The research in this article can provide a reference for the maneuverability design of submarine. © 2023 The Author(s).     

Robust adaptive course-keeping control of under-actuated ships with the rudder failure北大核心CSCD

[目的]针对舵机故障、控制增益未知和海洋环境干扰情况下的欠驱动船舶航向保持问题,设计一种考虑舵机故障的船舶鲁棒自适应航向保持控制算法。[方法]通过结合鲁棒神经阻尼技术和自适应方法,对繁重的神经网络权值进行横向压缩,仅需设计2个自适应学习参数对未知增益和舵机故障参数在线补偿,以确保船舶在舵机故障的情况下能够有效执行航向保持任务。通过李雅普诺夫理论,证明所提出的控制器半全局最终一致稳定有界(semi-global uniform and ultimately bounded,SGUUB)。最后以“育鲲”轮为仿真对象,建立非线性Nomoto数学模型,在海洋干扰下进行对比仿真试验验证。[结果]结果表明,在此策略下,“育鲲”轮在舵机故障情况下平均舵角输出比仿真试验中所对比的传统方法降低了51%,可改善航向保持控制效果。[结论]研究结果可为欠驱动船舶的航向保持控制问题提供借鉴。     

共享车辆基地的城轨车底运用与检修计划协同编制

科学的列车车底运用计划是实现轨道交通运营秩序顺畅和能源节约等目标的重要保证。在城市轨道交通土地资源合理运用的前提下，协同优化车底运用与维修养护有助于充分利用车底资源。本文以共享车辆基地的多条城市轨道交通线路的车底资源运用计划为研究对象，研究基于多线多车辆段基础设施网络的车底运用计划与检修计划的联合编制问题，以车底运用及检修成本最小为优化目标，以车底运用状态和检修累计值为决策变量，考虑车底连接约束、检修约束及车辆段检修能力约束，构建混合整数线性规划模型，并提出一种混合启发式算法进行求解。以某市地铁为例，结果表明，网络运营比单线独立运用的总运营成本减少了8.1%，验证了模型及算法的有效性。通过确定合理的编制周期和车辆段检修功能布局可进一步实现车底资源的优化配置，为相关部门合理进行车辆段布局及车底运用提供参考。