Suppression of Wave-Excited Vibration of Offshore Platform by Use of Tuned Liquid Dampers

This paper describes experimenlal and theoretical investigations of Tuned Liquid Damper (TLD) characteristics tor suppressing the wave-excited structural vibration. The structural model lor the experiments is scaled according to a full size offshore platform by matching their dynamic properties. Rectangular TLDs of different sizes with partially filled liquid are examined. By observing the performance and behavior of TLDs through laboratory experiments, the study investigates the influence of a number of parameters, including container size, container shape, frequency ratio, and incident wave characteristics. In an analytical study, a mathematical model that describes the nonlinear behavior of liquid in TLD and the interaction of TLD and structure is prerequisite. The validity of the model is evaluated and simulating results can reasonably match the corresponding experimental results.     

Offshore Structural Control Considering Fluid Structure Interaction

1.IntroductionAmong various control devices,Tuned Mass Damper(TMD)has been mostfrequently usedtothecontrol of structural vibration induced by oscillating loads such as earthquakes,winds,and waves.This is due to the fact that it operates without external e…     

内流对海底管线涡致振动与疲劳寿命的影响

在复杂的海洋环境条件下，管道的动力学特性受到内外部流体的作用而呈现出新的特点。本文通过对处在海底平稳流动作用下的悬跨管道的涡致振动进行分析，特别地考虑到管道内部流动的作用，给出了内流速度对管道响应幅度的影响，进而指出其对管道疲劳的意义。     

The OH Maser Line Receiving System for the Urumqi 25m Radio Telescope

A maser spectral line system is newly implemented on the Urumqi 25m Radio Telescope. The system consists mainly of a cooling receiver and a 4096 channels digital correlation spectrometer. The frequency resolution of the spectrometer at the maximum signal bandwidth of 80MHz is 19.5kHz. After careful calibrations observation at the 1665 MHz OH maser emission was made towards a number of sources, including W49N and W75N. The observed results demonstrate that the digital correlation spectrometer is suitable for astronomical spectral line observations.     

周期性四组元局域共振桩带隙特征及隔振性能研究

基于既有的三组元局域共振结构,考虑到岩土材料流塑性及弹塑性特征,提出一种由管桩、软体层、桩芯和基体组成的四组元局域共振桩结构,并基于周期性理论,利用频散曲线分析了管桩密度、弹性模量、厚度对四组元结构带隙特征影响。研究发现：相比于无管桩的三组元结构,带管桩的四组元结构更加容易出现完全带隙,且管桩只对带隙上边界产生影响;相比于管桩密度,管桩弹性模量可对四组元结构带隙产生质变影响,影响程度更大;通过四组元结构带隙边界点模态分析,确立了四组元结构带隙计算公式。通过时域分析发现,相比于三组元结构,四组元结构在带隙内振动衰减效果可提升近30%,其内在原因是四组元结构中管桩提高了基体整体刚度,从而有效地预防了基体“击穿”带及泄露波的出现。相关研究可为新型局域共振结构设计及隔振效果改善提供新思路。     

煤矿井下套铣打捞技术研究与应用

基于煤矿开采深度的增加,在复杂地层中进行定向钻孔施工发生卡钻事故的风险也在急剧增加。采用套铣打捞技术进行卡钻事故处理,能够提高事故处理的成功率,并起到保护原钻杆的作用,降低经济损失。文章分析研究了套铣打捞钻具的选择、冲洗液选择、工艺参数以及工艺方法,结合在玉溪矿和临涣矿打捞实例,优化了套铣打捞工艺及相关参数。     

分离盘控制圆柱涡激振动的数值模拟研究

圆柱涡激振动问题一直以来备受关注,分离盘作为涡激振动抑制装置得到广泛研究。分离盘长度L与圆柱直径D之比L/D是影响抑制效果的主要因素。运用有限体积法结合RANS方程与一定的湍流模式离散和求解流场,通过编写自定义程序,使用动网格模拟结构物的运动带来的流域边界的变化,针对弹性支撑的圆柱及附加长度为0.5 D的分离盘模型,在约化速度Ur为2.5~13的情况下,对涡激振动及其抑制进行研究。结果表明:分离盘可以抑制甚至消除圆柱涡激振动,99%以上的振幅被抑制;锁定区始点被推后,锁定区变窄;附加分离盘的圆柱阻力和升力被抑制;其斯特鲁哈数(St)稍高于单圆柱St但差别不大。     

地铁列车荷载作用下Duxseal-WIB隔振性能数值分析

城市轨道交通快速便捷的同时,地铁运行产生的环境振动问题也日益突出。Duxseal作为一种工业填料,具有良好的阻尼性能并能吸收振动反射能,将其运用到地铁隔振中,提出一种带孔波阻板填充Duxseal(DXWIB)的隔振方法。通过建立三维ABAQUS有限元模型,对比分析波阻板(WIB)、蜂窝状波阻板(HWIB)和DXWIB的隔振效果,讨论DXWIB埋置深度及厚度对隔振效果的影响,并分析基床表层和地面的振动规律。计算结果表明:DXWIB的隔振效果最优,而WIB与HWIB的隔振效果相近;DXWIB在埋深0.5 m厚度0.8 m时隔振效果最佳;基床表层的振动规律表现为由振源向两侧横向传播中,加速度整体呈衰减趋势,而在地面传播过程中,加速度峰值呈先增大后减小再增大的趋势,在距轨道中轴线20 m和50 m处出现局部放大效应。     

振动切喷技术在重庆草街航电枢纽工程中的应用

在振动切刀下部安装有定喷的喷嘴,振动切槽之前,超前进行定喷,将振动切槽与定喷两种工艺综合成一种工艺,构成一种新的薄防渗墙的施工工艺——振动切喷技术。介绍了该新技术在重庆草街航电枢纽工程中的应用情况,实践证明,此工艺提高了防渗墙的施工效率与成墙质量。     

Characteristics of infrared point sources associated with OH masers

We collect 3249 OH maser sources from the literature published up to April 2007, and compile a new catalog of OH masers. We look for the exciting sources of these masers and their infrared properties from IRAS and MSX data, and make a statistical study. MSX sources associated with stellar 1612 MHz OH masers are located mainly above the blackbody line; this is caused by the dust absorption of stellar envelopes, especially in the MSX A band. The mid-IR sources associated with stellar OH masers are concentrate...