大型复杂结构低频线谱振动优化设计研究

发布时间：2018-05-09 22:29

本文选题：海洋平台 + 低频线谱振动　；参考：《哈尔滨工程大学》2016年硕士论文

【摘要】：21世纪以来,世界各国在船舶与海洋结构物及其配套设备方面的建造日趋大型化、复杂化、多样化,由此带来的结构振动问题日趋严重;与此同时,国际标准化组织ISO 6954:1984、2000(E)《机械振动和冲击—商船振动的综合评价标准》对海洋平台及船舶振动提出了更高的要求;因此,如何有效降低大型复杂结构的振动响应,特别是由船载设备引起的共振响应,已经成为工程领域中亟待解决的问题。为此,本文首先对船舶与海洋结构物振动控制方法概况进行了阐述,对几种振动控制方法存在的不足及难点进行了分析。分析结果表明,主动控制技术因需要外界能源的输入,且由于开发研究时间较短存在技术复杂、造价较高、可靠性较低等缺点,尚未在工程中广泛应用;被动控制技术具有结构简单、经济性好、易于操作且不需要外部能源的供给等优点,有较好的工程应用前景。针对上述问题,本文拟以吸振原理为基础,将动力吸振器应用到大型复杂结构低频线谱振动控制中,形成应用于大型复杂结构低频线谱振动控制的动力吸振系统化方法。首先,本文阐述了动力吸振原理,建立了动力吸振数学模型,得到了振动系统主结构的稳态响应幅值函数;在此基础上,讨论了动力吸振器与主结构最优质量比、最优阻尼比、最优频率比的取值范围,以及动力吸振器的最优布置数量和最优布置位置等。结果表明,动力吸振器其它参数在一定条件下,质量比越大,振动系统主结构的稳态响应幅值越小;阻尼比越大,振动系统主结构的稳态响应幅值越小;频率比越接近1,振动系统主结构的稳态响应幅值越小;总质量相等的前提下,动力吸振器布置数量越多,振动系统主结构的稳态响应幅值越小。在上述研究的基础上,总结形成了应用于大型复杂结构低频线谱振动控制的动力吸振系统化方法流程,并以船舶与海洋结构物典型连接构件为例,开展了动力吸振系统化方法的有效性验证。结果表明:动力吸振系统化方法能较好地应用于船舶与海洋结构物典型连接构件,典型考核位置的振动响应随动力吸振器各参数的变化与理论推导保持一致,初步验证了动力吸振系统化方法的有效性,为大型复杂结构低频线谱振动定量预报及相关研究提供了方法依据。最后,将动力吸振系统化方法应用于某海洋平台上层建筑的振动响应控制中,分析了海洋平台上层建筑典型舱室的振动特性,针对该海洋平台实际工程问题,提出了三种动力吸振器布置方案,并通过改变动力吸振器参数对减振效果不佳的布置方案进行了优化设计,为海洋平台等大型复杂结构实船振动控制提供了参考。
[Abstract]:Since the 21st century, the construction of ships and marine structures and their supporting equipment has become more and more large, complicated and diversified, and the structural vibration problem has become more and more serious. The International Organization for Standardization (ISO 6954: 1984 / 2000E) "Comprehensive Evaluation Standard for Mechanical Vibration and shock-Merchant ship Vibration" puts forward higher requirements for the vibration of offshore platforms and ships, therefore, how to effectively reduce the vibration response of large and complex structures, Especially the resonance response caused by ship-borne equipment has become an urgent problem in engineering field. In this paper, firstly, the general situation of vibration control methods for ships and marine structures is described, and the shortcomings and difficulties of several vibration control methods are analyzed. The analysis results show that the active control technology has not been widely used in engineering because of the need of external energy input, and because of the shortcomings of complex technology, high cost and low reliability in the short time of development and research. Passive control technology has the advantages of simple structure, good economy, easy operation and no need of external energy supply, so it has a good prospect of engineering application. In view of the above problems, based on the principle of vibration absorption, the dynamic vibration absorber is applied to the control of low frequency linear spectrum vibration of large complex structures, and a systematic method of dynamic vibration absorption is formed for the control of low frequency linear spectrum vibration of large complex structures. Firstly, this paper describes the principle of dynamic vibration absorption, establishes the mathematical model of dynamic vibration absorption, and obtains the steady-state response amplitude function of the main structure of vibration system, and on this basis, discusses the best quantity ratio of dynamic vibration absorber and main structure, the optimal damping ratio. The range of the optimal frequency ratio, the optimal arrangement number and location of the dynamic vibration absorber, etc. The results show that under certain conditions, the larger the mass ratio, the smaller the steady-state response amplitude of the main structure of the vibration system, and the smaller the amplitude of the steady-state response of the main structure of the vibration system is the larger the damping ratio is. The closer the frequency ratio is to 1, the smaller the steady-state response amplitude of the main structure of vibration system is, and the smaller the steady state response amplitude of the main structure of vibration system is when the total mass is equal, the more the number of dynamic vibration absorbers is, the smaller the steady-state response amplitude of the main structure of vibration system is. On the basis of the above research, a systematic method of dynamic vibration absorption applied to the control of low frequency linear spectrum vibration of large and complex structures is summarized, and a typical connection member between ship and ocean structure is taken as an example. The effectiveness of the dynamic vibration absorption systematization method is verified. The results show that the dynamic vibration absorption systematization method can be applied to the typical connection members of ship and ocean structures, and the vibration response of the typical check position is consistent with the theoretical derivation with the variation of the parameters of the dynamic vibration absorber. The effectiveness of the systematization method of dynamic vibration absorption is preliminarily verified, which provides a basis for quantitative prediction of low frequency linear spectrum vibration of large complex structures and related research. Finally, the dynamic vibration absorption systematization method is applied to the vibration response control of an offshore platform superstructure, and the vibration characteristics of the typical cabin of the offshore platform superstructure are analyzed, and the actual engineering problems of the offshore platform are analyzed. Three kinds of layout schemes of dynamic vibration absorbers are put forward, and the optimal design of the layout scheme with poor damping effect is carried out by changing the parameters of the dynamic vibration absorbers, which provides a reference for the vibration control of large and complex ships with complex structures such as offshore platforms.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U661.44;P75

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