【作者】 霍发力；

【导师】 吴立人； 嵇春艳；

【作者基本信息】 江苏科技大学 ， 船舶与海洋结构物设计制造， 2009， 硕士

【摘要】 海洋平台在服役期间会受到风、浪、流甚至冰以及地震等载荷的作用。在这种连续性、长期性环境载荷作用,海洋平台结构会发生明显、连续的振动,从而加剧了平台的疲劳破坏、增加生产风险,同时影响了平台作业人人员的工作环境,因此,海洋平台的振动控制成为工程界十分关注的课题。本文基于线性波浪理论、采用Morison方程计算随机波浪力,分析了海洋平台在随机波浪载荷下所表现的动力响应特性,以及磁流变阻尼器阻尼的特点,对海洋平台的半主动振动控制方法进行了理论和模型试验的研究。本论文主要研究内容包括:◆采用线性波浪理论、Morison方程、波浪力谱分析方法计算随机波浪力,并进行了数值模拟。◆建立了海洋平台结构振动方程,并分别从频域和时域给出了振动方程的求解方法,以一典型的海洋平台为数值算例,对实际海洋平台的振动响应进行了时域和频域分析,给出了平台的振动响应特征。◆将平台结构视为多自由度系统,推导出了加有控制装置后平台振动方程,基于滑移模态控制和模糊控制等智能振动控制理论,采用磁流变阻尼器为半主动控制实现装置给出了海洋平台结构的半主动控制系统设计方法,并以一典型的海洋导管架式平台为数值算例,进行了减振效果的数值仿真。◆以一典型导管架式海洋平台为原型,根据动力相似准则按1:50比例设计海洋平台结构模型,采用减振效果较好的模糊控制理论设计了针对该海洋平台结构模型的磁流变阻尼器半主动式振动控制系统,并对其在规则波及随机波设计实验工况下的减振效果进行了数值仿真。◆基于本文所发展的海洋平台结构模型设计方法及半主动式控制设计原理,实际制作典型导管架海洋平台模型及磁流变阻尼器(MR)为控制器的半主动控制系统,并在波浪水池中进行了多种工况模型试验,对平台在随机波、规则波作用下的减振效果进行了模型试验研究,并将数值模拟结果和模型试验结果进行了比较分析。结果表明,设计的控制系统对海洋平台在波浪载荷下的振动响应控制效果在30%以上,起到了很好的控制效果。更多还原

【Abstract】 For the environments of the offshore platforms, the offshore platforms inevitably undergo the environment loads during the service time such as wind, waves, current, ice and earthquake ete, especially continuous and longtime wave load which will induce continuous vibration of the offshore platforms. First and foremost, the continuous vibration will cause fatigue damage, which will reduces the reliability and the avail using years. Besides, the continuous vibration will increase the venture and the investment. At the same time, the surroundings or the operators will be worsened for the vibration. With the development of the vibration control of building in land, the control technology of the offshore platform has become a very important research subject on ocean engineering and academic fields.This thesis studies the dynamic properties of offshore platforms under random wave loading and the traits of the magnetorheological fluid damper (MRFD), furthermore, using the theory and experimentation metholds, studies the semi-active reducing vibration methold of the offshore platforms. The major research is shown as following:◆With the line wave theory, Morison equation and wave force spectrum the random wave force was calculated, and the numerical simulation was finished.◆The structure vibration equation was erected, the solution of the vibration equation was gave from spectrum field and time field. A typical jacket offshore platform as a numerical example, the platform vibration response was analysed from time field and spectrum field, and the vibration response characters were given.◆The vibration equation with control fitting was deduced when the platform is as multiple degrees of freedom system. On the basis of the sliding mode control and fuzzy control, the method of the platform structure semi-active vibration control system was given using the MRFD as the control fitting. Used a typical jacket offshore platform as a numerical example, the numerical simulation of the vibration control effect was done.◆On the basis of similarity criterion on dynamics the platform model was designed with the scale of 1:50 by the typical jacket platform. The MRFD semi-active control system for the model was designed using the fuzzy control theory, and numerical simulation of the vibration control effects were finished under the random wave and regular wave load cases.◆On the basis of the platform model design scheme and the semi-active control design theory, the model and the MRFD control system were made, and the model experiment was did in the wave water basin. Studied the vibration control effects under random wave and regular wave load cases, the experimental results compared with the numerical simulational results. The results show that the MRFD system designed can reduce the vibration of the platforms effectively, reduced above more 30%, and in the same time the control effect is stable.更多还原