高速公路标志设置的几点问题及建议

针对目前高速公路上标志设置普遍存在的问题进行分析，给出常见情况下视认距离和设置密度的计算公式，并对存在的问题提出改进建议，可为高速公路标志的设置和改造提供参考。     

一种多通道信息融合的横向减振器性能退化阶段辨别方法

对于转向架这样复杂的系统,分布在系统不同位置的传感器可以实时检测大量数据。这些数据能够反映高速列车运行过程中转向架关键部件的性能退化状态,但单一通道的振动信号存在着信息缺失、信噪比低等缺陷,无法据此实现转向架关键部件性能退化阶段的精确辨识。因此,本文以横向减振器为研究对象,通过对转向架振动数据相关性分析,提出了车体和转向架上多个通道的振动信号共同用于横向减振器性能退化阶段辨识的方法。并通过构建基于CNN的多通道信息融合模型,将多个通道信息进行融合,实现了横向减振器性能退化特征的自适应提取与阶段辨识。将该方法与基于单个通道的方法进行比较,结果表明,该方法能够精确实现横向减振器间隔10%的性能退化阶段辨识。     

Semi-active H∞ control of high-speed railway vehicle suspension with magnetorheological dampers

In this paper, semi-active H∞ control with magnetorheological (MR) dampers for railway vehicle suspension systems to improve the lateral ride quality is investigated. The proposed semi-active controller is composed of a H∞ controller as the system controller and an adaptive neuro-fuzzy inference system (ANFIS) inverse MR damper model as the damper controller. First, a 17-degree-of-freedom model for a full-scale railway vehicle is developed and the random track irregularities are modelled. Then a modified Bouc–Wen model is built to characterise the forward dynamic characteristics of the MR damper and an inverse MR damper model is built with the ANFIS technique. Furthermore, a H∞ controller composed of a yaw motion controller and a rolling pendulum motion (lateral motion+roll motion) controller is established. By integrating the H∞ controller with the ANFIS inverse model, a semi-active H∞ controller for the railway vehicle is finally proposed. Simulation results indicate that the proposed semi-active suspension system possesses better attenuation ability for the vibrations of the car body than the passive suspension system.     

基于MR阻尼器的船用隔离器系统试验研究

随着船舶技术的发展，现代船舶对船用隔离器系统提出了越来越高的要求，即船用隔离器系统应同时具备低频减振和高频抗冲击的能力，这是传统的船用减振器系统所无法做到的．为了解决此问题，本文提出了一种新的船用隔离器系统，该系统由钢丝绳弹簧和磁流变阻尼器相并联组成．文中对该船用隔离器系统的减振和抗冲击性能进行了模型试验研究。减振试验的激振力频率为1-15Hz，力幅为2．94．11．76kN；冲击试验的最大冲击输入加速度为20g，脉宽为10ms，减振试验和冲击试验均采用MTS液压加载系统来进行．试验结果表明，该船用隔离器系统具有较好的减振效果，使用了MR阻尼器后系统得共振峰值被明显的削弱；在冲击试验中，冲击响应的衰减速度随着MR阻尼器的阻尼增加而明显加快，但是MR阻尼器再冲击瞬间的出力特性明显与低频振动情况下不同，MR阻尼器的出力表现为受控制电流强度影响不大．     

悬索桥吊索高阶涡激振动及摆锤式MTMD减振技术研究

为了解大跨度悬索桥吊索出现的大幅高频振动现象,并进行减振,以国内某主跨1688 m的悬索桥为背景(最长吊索长184.6 m),基于理论方法和施工期吊索大幅高频振动实测结果,分析吊索的振动类型及参数(频率、阻尼比);提出一种摆锤式多重调谐质量阻尼器(MTMD,其由一定形状的锤头提供质量参数,由钢绞线提供刚度及阻尼参数),采用有限元和室内试验的方法,分析其振动特性,并进行实桥验证。结果表明:该桥吊索振动频率范围为5~25 Hz,阻尼比低,单个吊点的多根吊索易发生同相位的高阶涡激振动;摆锤式MTMD单个锤头具有2个控制主频,自身阻尼比约10%,具有位移放大作用,对高频振动的响应灵敏,在很宽的频率范围内具有很好的减振性能;摆锤式MTMD可有效增加吊索自身阻尼比,控制吊索高阶涡激振动,实测减振效果达到90%以上,具有很好的实用性。     

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.     

鱼雷被动声自导反舰深度设定方法

鱼雷被动声自导反舰时,搜索深度的设定决定了鱼雷效能的发挥。采用鱼雷被动自导作用距离作为鱼雷搜索深度设定依据。被动自导方程各项中,鱼雷自噪声级与传播损失随深度变化,二者在深度上的分布决定了不同深度上自导作用距离的差别。采用声散射模型计算鱼雷自噪声级,采用Bellhop模型计算传播损失,结合被动自导方程其他各项的仿真和计算,定量分析4种典型水文条件下自导作用距离随深度变化情况,并提出被动自导系统搜索深度设定原则。     

锚杆注浆浆液参数优化研究

论述锚杆注浆的重要作用及不同配合比的浆液对工作性能的影响,探讨不同水灰比、速凝剂掺量、砂浆的灰砂比的用量对于浆液性能的影响,提出优化后的浆液配比,为今后类似工程提供参考。     

某人行天桥病害分析及加固措施

主要对某钢结构人行天桥的主要病害做出了分析,对桥梁加固改造措施中也提出了一些见解,同时在加固措施方案中引进了一种新技术在箱梁内部安装调频质量阻尼器(TMD),大大地降低钢箱梁共振效应,减少行人的不安全感,保证桥梁的安全运营和耐久性能,对其他类似的桥梁加固提供了一定的借鉴经验。     

磁流变阻尼器动态特性研究

为更好地研究磁流变阻尼器应用于舰船设备抗冲击的控制方法,需要准确、全面了解其动态力学特性。对磁流变阻尼器的动态特性进行试验研究,详细讨论速度、振幅、频率、电流等各个因素对阻尼力的影响。结果表明,在低速区域阻尼器的阻尼力以不可控的粘滞阻尼力为主,阻尼力随速度的变化明显;在高速区域,阻尼力以磁流变液屈服引起的库仑阻尼力为主,阻尼力随速度的变化不大,而主要决定于控制电流,但是随着电流的增大,出现饱和现象;振幅和频率主要影响磁流变阻尼力的粘滞阻尼力,随频率和振幅的增加,速度的变化范围也明显增大,但是在相同的速度下,频率和振幅对阻尼力的影响不明显。为进一步获得磁流变阻尼器动态特性参数及研究舰船设备抗冲击半主动控制方法提供了重要依据。