固定式导管架平台的H2振动控制技术研究

基于H2控制原理，研究了在无法获得海洋平台精确数学模型时仍能实施有效控制的振动控制技术。通过采用一滤波器来近似随机波浪力的设计方法，解决了将H2控制原理应用于海洋平台振动控制中非高斯白噪声的输入问题。此外，为了更清晰地描述海洋平台所具有的不确定性，在建立其数学模型时，将模拟随机波浪力的噪声与模型噪声分开表示。以一典型的固定式导管架平台为数值算例，研究了该控制方法对固定式导管架平台振动的控制效果，并对系统的不确定性进行了敏感性分析。仿真结果表明，该控制方法对固定式导管架平台在随机波浪荷载作用下出现超大振动的控制是有效的，并具有一定的鲁棒性能。     

平湖油气田往复式压缩机振动故障实例分析

针对海洋石油平台常见的往复式压缩机振动失效故障,运用振动分析方法,对其产生的振动故障类型进行总结,并针对平湖平台往复式压缩机的各种振动实例问题提出一系列的解决方法,为今后同类型设备的维护和运行提供一个整改范例,也为今后海洋石油平台的压缩机工程设计、成撬和安装及运行提出了改进方向。     

海洋工程结构故障的模式识别诊断

本文提出固定式导管架平台结构故障的模式识别诊断.首先介绍模式识别的基本思想,然后讨论统计判别函数方法.对一个二维导管架平台模型,用随机激励进行了正常平台、台面质量增加、横撑斜撑切断以及根部开裂等多种结构状态的振动试验.取频响函数幅值和随机减量函数作为被识别的模式,得到了很好的结果,从而说明这是一种很有希望的导管架平台结构故障的诊断方法.     

海洋平台油气管道疲劳裂纹AE信号特征提取及识别研究

为了将声发射(AE)技术实际应用到监测海洋平台油气管道疲劳裂纹中,需要解决管道振动干扰以及疲劳裂纹AE信号有效特征提取的问题,而问题的关键在于对管道结构疲劳裂纹AE信号特征提取及识别算法的研究。在已有研究的基础上,提出了一种基于经验模态分解(EMD)为特征提取的疲劳裂纹识别方法,将管道振动干扰问题和疲劳裂纹AE信号有效特征提取问题联系在一起,对特征元素进行优化并剔除无效噪声干扰信息,通过概率神经网络(PNN)对疲劳裂纹信号进行识别。试验结果表明,PNN结合基于EMD为特征提取的疲劳裂纹识别法能够取得良好的效果,为声发射技术监测海洋平台油气管道疲劳裂纹提供了试验和理论依据。     

Tensor Properties of Added-mass and Damping Coefficients

It has been shown that in the context of a linear theory for a floating body with six degrees of freedom each of the 6× 6 added-mass and damping matrices contains three distinct Cartesian second-order tensors in regard to translational, rotational and interaction between translational and rotational oscillations. As a result of this, a new technique based on the transformation law of second-order tensors is introduced for motion analysis of offshore platforms which can be used as an alternative to the common methods in offshore engineering.     

海洋平台结构振动控制综述

振动将会影响平台工作人员的身心健康，导致结构疲劳和破坏，降低平台的实用性和生存性，给生产生活带来极大威胁。对结构振动控制的研究和应用现状作了回顾，总结了国内外海洋平台振动控制的研究进展，并对今后的研究提出了建议和展望。     

一种海洋平台广义模型修正方法的研究

针对导管架式海洋平台结构的广义模型修正问题，提出了先修正模态振型后修正模态频率的试验方法。首先利用损伤检测方法识别出试验模型中与初始有限元模型有刚度偏差的杆件单元并采用反复迭代修正的方法进行了有限元模型模态振型的修正；然后将地基模拟为三维弹性支承并对其进行优化设计来实现有限元模型模态频率的修正；通过力锤激励下海洋平台的模型试验验证了此方法的可行性，为长期服役且原型结构未测的海洋平台的损伤检测、安全评估研究提供了基础。     

多级离心泵振动故障诊断分析及处理

振动是影响离心泵机组安全可靠性运行的重要因素。针对某石化公司多级离心泵振动超标、不能正常运行等问题，借助北京京航公司HG8908C数据采集系统进行振动测试，运用频谱分析方法对其振动信号幅域、时域、频域详细诊断分析，给出其可能的故障因素，并结合解体情况提出调整转子中心、适当增大叶轮出口与导叶进口间的动静间隙等相关方案，有效地解决了振动故障问题，提高了泵组的可靠性。此方法及解决措施对类似振动故障问题具有一定参考价值和指导意义。     

Application of RCM for safety considerations in a steel plant

Any operation or process done on machine or its parts to enhance the efficiency of machine before or after the breakdown is called maintenance. A concern may be said to be successful over the years, when it runs non-interrupted, maintains a smooth production flow consistently and at optimum productivity levels. Plant can achieve productivity up to a satisfactory level by proper maintenance work. The maintenance system may be categorized as either ‘Planned’ or ‘Unplanned‘. The classic maintenance problems in modern industries are insufficient pro-active maintenance, frequent problem repetition, erroneous maintenance work, sound maintenance practices not institutionalized, unnecessary and conservative PM, sketchy rationale for PM actions, lack of traceability/visibility for maintenance program, blind acceptance of OEM inputs, PM variability between like/similar units, paucity of predictive maintenance applications. Hence it was necessary to develop an appropriate methodology to develop strategies and programmatic approach to deal with such problems. The reliability centered maintenance offers the most systematic and efficient process to address an overall programmatic approach to the optimization of plant and equipment maintenanceIn this paper, the concept of RCM has been applied to process of vacuum degassing/vacuum oxygen decarburising (VD/VOD) in steel melting shop of a medium scale steel industry. Safety consideration is the significant aspect for selection of the system. By systematically applying the RCM methodology, failures, failure modes are analyzed. To preserve the system function, preventive maintenance tasks such as inspection/checking, lubrication, cleaning, adjustment, replacement, are allotted for various failure modes. RCM based preventive maintenance schedule for the system is formulated and compared with the company's existing preventive maintenance schedule. For subsystems such as ejectors, water-ring pumps and the RLC/ladle car/furnace, existing maintenance schedule is conservative. For oxygen lance and cooling pumps, maintenance frequency is to be increased to quarterly from yearly in the present schedule. For condensers bimonthly schedule is recommended as compared to none, whereas for cooling pumps the schedule remains unchanged. This reveals that RCM based tasks need not necessarily increase the frequency but can, retain or even decrease the frequency of maintenance based on functional priorities. RCM can also recommend the additional maintenance tasks. Application of RCM based PM schedule requires use of age exploration technique and attitudinal changes.     

Rotational torsion fatigue failure of an engine driven fuel pump coupling

Between 2005 and 2007 serious flight safety concerns arose when a small fleet of single engine basic trainer aircraft experienced five critical failures of engine driven fuel pump (EDFP) couplings, and a further instance of a cracked coupling. Consequent investigations showed that the coupling fractures were likely to have been caused by a combination of reverse torsional loading and bending. Engine ground runs were then carried out to evaluate linear and torsional engine vibration levels in the drive train affecting the fuel pumps. Analysis of the vibration data indicated that engines, which had caused pump‐coupling failures exhibited high‐amplitude torsional vibration at certain power settings. The excessive vibration level was eventually attributed to detuning of the crankshaft counterweight dampers. This investigation resulted in a change to the maintenance practises on the aircraft in question and no fuel pump failures have occurred since December 2008.     

Comment on “A framework to practical predictive maintenance modeling for multi-state systems” by Tan C.M. and Raghavan N. [Reliab Eng Syst Saf 2008;93(8):1138-50]

“System-perspective” proposed by “A framework to practical predictive maintenance modeling for multi-state systems” by Tan C.M. and Raghavan N. [A framework to practical predictive maintenance modeling for multi-state systems. Reliab Eng Syst Saf 2008;93(8):1138-50] is a very useful method to evaluate and optimize the maintenance strategy for complex systems, especially for multi-state systems (MSS). The commented paper proposes an innovative process and modeling method to present imperfect maintenance effects on MSS, but there exist some incorrect points and misunderstandings. In this paper, these problems are pointed out and are attempted to be corrected under the original framework of the commented paper.     

机器引起的振动问题及对策

通过几个实例分析讨论由于机器引起的振动问题及对策。首先介绍实例为颚式破碎机引起周围民房产生振动，然后是一宾馆冷却水泵引起的振动，最后为纺织机械引起的多层织造厂房的结构振动的实例。     

波浪传播方向对导管架海洋平台模态识别的影响及对策

为了提高不规则波载荷下海洋平台的模态识别精度,通过分析波浪传播方向上的桩腿间距对平台波浪合力频率特性的影响规律,针对4桩腿导管架平台提出了一种寻找波浪合力峰频与谷频的方法,并在该方法的基础上针对各个低阶模态识别提出了选择合适的波浪入射角范围来避免波浪合力有色噪声干扰的方法。然后通过对一个典型的4桩腿导管架平台的数值模拟分析,验证了寻找平台波浪合力峰频与谷频的方法,分析了波浪合力峰频与谷频对模态识别的干扰规律,并针对3个低阶模态找出了适合模态识别的波浪入射角范围。     

云南省某剧院空调通风设计

云南省某剧院采用直膨式全空气空调系统,空调系统由室外机直接蒸发式全空气处理机组两部分组成,无需水泵、冷却塔等设备,安装使用及维护方便。机组置于屋顶或者室外空地,无需机房,节省初投资,维修方便。机组不需要二次冷媒,系统效率高。剧院采用大风道,消声减震处理较为简单。介绍剧院直膨式空调系统、通风系统设计,包括空调冷热源、空调系统、防排烟系统、节能、自控、消声与隔振处理,直膨机与其他空调冷热源方案对比等内容。     

Aufbau und Eigenschaften verschiedener ölfreier Vakuumpumpen für den Grob- und Feinvakuumbereich

The development of high vacuum pumps and systems during the last 35 years can be characterized by a trend of gradual elimination of liquids exposed to vacuum environment. The need for high purity vacuum process equipment precipitated the development of new pumping techniques: iongettering pumps, turbomolecular pumps and cryopumps. During the last 5 years, a number of dry coarse-vacuum pumps have been developed. Some are entirely oilfree, some still use lubricants at the seals separating the driving mechanism from the vacuum side. This review contains general design and performance characteristics of four classes of equipment: hermetically sealed pumps using bellows to isolate the driving mechanism, a variety of multistaged positive displacement blowers, pumping trains based on turbo-drag pumps, and multistaged reciprocal piston pumps. It is entirely practical to achieve pressure of 10⁵ to 10⁶ while discharging to atmosphere. Despite a complete absence of conventional lubrication in some of these pumps, periods exceeding 10000 hours without maintenance are obtained, providing a viable technology for clean vacuum systems.     

Optimization Design of TMD for Vibration Suppression of Offshore Floating Wind Turbine

In order to suppress the responses of the large vibration displacements and loads of the offshore floating wind turbine under the harsh marine environment,an effect method for restraining vibration,putting tuned mass dampers( TMD) in the cabin of wind turbine,is proposed in this paper.A dynamics model for offshore floating wind turbine with a fore-aft TMD is established based on Lagrange equation; Parameter identification of the wind turbine is performed by the non-linear least squares Levenberg-Marquardt( LM) algorithm; Parameter optimization of the TMD is researched when considering the standard deviation of the tower top longitudinal displacements as the objective function.Aiming at five typical combined wind and wave load cases under normal running state of the wind turbine,the dynamic responses of the wind turbine with / without TMD are simulated and the suppression effect of the TMD is investigated.The results show that:there exists the optimum TMD mass ratio1.8% when the damped free vibration of the wind turbine,and the standard deviation of the tower top longitudinal displacements is decreased 60% in 100 seconds by the optimized TMD.The standard deviation suppression rates of the longitudinal displacements and loads about the tower and blades increase with the increasing TMD mass ratio when the wind turbine vibration under the combined wind and wave load cases,and when the mass ratio changes from 0.5% to 2%,the maximum suppression rates are from 20% to 50%,which effectively reduce the vibration responses of the wind turbine.The research results of this paper preliminarily verify the feasibilities of using TMD for restraining vibration of the offshore floating wind turbine.     

机泵群实时监测网络和故障诊断专家系统

应用现代信息技术和人工智能实施设备诊断工程,逐步实现状态维修和预知维修,是大型流程工业企业降低生产成本的重要途径之一。概要介绍为实现这一目标所开发的机电装备实时监测网络和人工智能诊断技术。简要介绍了基于Ethernet和FDDI开发、应用于石化企业的机、泵群实时监测网络;首次提出了黑灰白集合筛选法,在一次原因分析法和故障机理及其识别特征研究基础上,应用此方法开发的基于黑灰白集合筛选法的机械故障诊断专家系统,用于工程实践取得了满意的结果。     

叶片泵振动机理特性分析及改进设计

机械设备振动和设备组成、工作机理、工作状态等息息相关,船用常见设备如水泵、风机等由于工作机理各不相同,其振动频率特性也各不相同。通过对旋转类设备振动特征进行对比分析,分析设备主要振源及其成因,提出设备改进方向,并进行针对性改进设计,试验结果表明,取得了良好的效果。     

二氧化碳压缩机低压缸振动故障分析与处理

通过具体案例,对二氧化碳压缩机低压缸的振动故障进行了分析,并提出了相应的检修处理方案和具体的防范措施.