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严重的船舶振动不仅影响船舶的居住舒适性,也是导致船体结构发生疲劳破坏及降低船舶设备仪表使用精度和寿命的元凶,因此在船舶设计阶段必须充分考虑船舶振动问题.文章基于某支线集装箱船,重点研究了船舶有限元振动响应计算中螺旋桨脉动压力的模拟方法;基于螺旋桨空泡试验测得的脉动压力和螺旋桨脉动压力的分布规律,提出3种不同的脉动压力模拟方法;通过对比研究不同模拟方法计算结果的差异,最终确定一种快速、高效且准确的螺旋桨脉动压力有限元模拟方法;应用该螺旋桨脉动压力模拟方法对某支线集装箱船进行全船振动响应分析,以实现船舶振动预报控制.经实船试航振动测试验证,该船振动性能良好. 相似文献
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船舶向肥大型化、高速化方向发展,船舶主机功率剧增,螺旋桨激振力引起的各类振动以及螺旋桨本身发生空泡剥蚀,影响了船舶的使用性能.本文介绍了能很好降低螺旋桨激振力的最近开发的高效和低振动两个系列螺旋桨情况和一些比较试验结果. 相似文献
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《舰船科学技术》2017,(20)
不论是远洋运输船舶还是军事舰艇,在正常航行时都不可避免的产生振动。振动会对船体造成一定的负面影响,比如检测设备的精度降低、船舶结构失效、噪声污染等。近年来,随着船载设备的精密程度和海上作业人员的舒适性要求不断提高,船舶振动性能的优劣受到了广泛重视。大型船舶是一个复杂的弹性结构件,振动的产生通常来自柴油主机、海浪和螺旋桨等方面,为了防止船舶正常运行时产生有害振动,对船舶的振动特性(固有振动频率、激振力等)进行研究具有重要的指导意义。本文利用有限元分析技术和振动数值模拟计算方法,对某货船进行振动特性分析,包括模态分析、振动激励分析等,对该货船的结构设计和减振方法有一定的指导意义。 相似文献
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船舶螺旋桨诱导的脉动压力和噪声的研究 总被引:1,自引:0,他引:1
随着人们对船舶振动和噪音问题的关注,对作为引起船舶振动和噪音源之一的螺旋桨的研究也愈来愈深入。本文从螺旋桨设计及船尾流场,包括附体设计等方面,研究降低螺旋桨诱导的脉动压力及船尾噪音的途径。 相似文献
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以研究螺旋桨水动力和离心力对船舶轴-桨组合振动特性的影响为本文的研究目的,基于W o r k-bench平台,采用流固耦合有限元分析方法,进行船舶轴-桨组合模态分析.在CFX中计算螺旋桨敞水性能,并在Ansys中将螺旋桨叶面水压力和离心力作为预应力分析轴桨组合振动的固有频率和振型,比较轴系、螺旋桨单独模型和轴-桨组合模型在固有频率上的区别.计算结果表明,轴桨组合的固有频率远远低于轴系和螺旋桨独立模型的固有频率;轴-桨旋转产生的离心力对其固有频率影响不大;螺旋桨在流场中产生的水压力略微提高纵向振动固有频率,但影响很小,在实际应用中可以忽略. 相似文献
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《船舶与海洋工程学报》2014,(1):126-126
正San Francisco,California,June 8-13,2014.OMAE 2014 is the ideal forum for researchers,engineers,managers,technicians and students from the scientific and industrial communities from around the world to:·meet and present advances in technology and its scientific support;·to exchange ideas and experiences whilst promoting technological progress and its application in industry·to promote international cooperation in ocean,offshore and arctic engineering.In line with the tradition of excellence of previous OMAE conferences,more than 900 technical papers are planned for presentation.Outreach for Engineers Specialty Forum This Specialty Forum is designed for students and professionals who may not be familiar with the Ocean and Offshore industry,as well as those who have just recently specialized in this field. 相似文献
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《船舶与海洋工程学报》2014,(2)
正November 4-6,2014Moody Gardens HotelConvention Center/Galveston,TX The Deepwater Operations Conference and Exhibition is celebrating its 12th anniversary this year.This growing event will continue the tradition of excellence in addressing operational challenges involved in developing deepwater resources.We will return to the Moody Gardens Hotel and Convention Center on November 5-7,2014 in Galveston,Texas. 相似文献
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《船舶与海洋工程学报》2014,(1)
正19–24 October 2014 SingaporeCONFERENCE THEMES The overall aim of the ICHD Conference is to provide a forum for participants from around the world to review,discuss and present the latest developments in the broad discipline of hydrodynamics and fluid mechanics.The first International Conference on Hydrodynamics(ICHD)was initiated in 1994 in Wuxi,China.Since then,9 more ICHD conferences were held subsequently in Hong Kong,Seoul,Yokohama,Tainan,Perth,Ischia,Nantes,Shanghai and St Petersburg.Evidently the ICHD conference has become an important event among academics,researchers,engineers and operators,working in the fields closely related to the science and technology of hydrodynamics.The 11th ICHD will be held in Singapore in 2014. 相似文献
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Lynne Zeitlin Hale Mark Amaral Abdulrahman S. Issa B. A. J. Mwandotto 《Coastal management》2013,41(1):75-85
Site-based projects were initiated in Chawka Bay-Paje, Zanzibar, and Nyali-Bamburi-Shanzu, Kenya, to demonstrate the benefits of an integrated coastal management (ICM) approach for addressing coastal issues such as tourism development and enhancement of resource-dependent village economies in eastern Africa. A two-year, multidonor project used three primary strategies to make rapid, but sustainable, progress toward ICM. These included using interagency government teams for ICM planning, adopting an internationally recognized framework for ICM as a project ''road map,'' and explicitly incorporating capacity-building strategies into all aspects of the project. Within two years, integrated ICM action strategies, prepared through participatory processes, were being implemented at both sites, and both teams were working to expand the scale and scope of ICM in their nation. More importantly, the project helped create committed, capable, interagency groups that continue to work together to address urgent ICM issues. 相似文献
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This paper presents a simplified method for the reliability- and the integrity-based optimal design of engineering systems and its application to offshore mooring systems. The design of structural systems is transitioning from the conventional methods, which are based on factors of safety, to more advanced methods, which require calculation of the failure probability of the designed system for each project. Using factors of safety to account for the uncertainties in the capacity (strength) or demands can lead to systems with different reliabilities. This is because the number and arrangement of components in each system and the correlation of their responses could be different, which could affect the system reliability. The generic factors of safety that are specified at the component level do not account for such differences. Still, using factors of safety, as a measure of system safety, is preferred by many engineers because of the simplicity in their application. The aim of this paper is to provide a simplified method for design of engineering systems that directly involves the system annual failure probability as a measure of system safety, concerning system strength limit state. In this method, using results of conventional deterministic analysis, the optimality factors for an integrity-based optimal design are used instead of generic safety factors to assure the system safety. The optimality factors, which estimate the necessary change in average component capacities, are computed especially for each component and a target system annual probability of system failure using regression models that estimate the effect of short and long term extreme events on structural response. Because in practice, it is convenient to use the return period as a measure to quantify the likelihood of extreme events, the regression model in this paper is a relationship between the component demands and the annual probability density function corresponding to every return period. This method accounts for the uncertainties in the environmental loads and structural capacities, and identifies the target mean capacity of each component for maximizing its integrity and meeting the reliability requirement. In addition, because various failure modes in a structural system can lead to different consequences (including damage costs), a method is introduced to compute optimality factors for designated failure modes. By calculating the probability of system failure, this method can be used for risk-based decision-making that considers the failure costs and consequences. The proposed method can also be used on existing structures to identify the riskiest components as part of inspection and improvement planning. The proposed method is discussed and illustrated considering offshore mooring systems. However, the method is general and applicable also to other engineering systems. In the case study of this paper, the method is first used to quantify the reliability of a mooring system, then this design is revised to meet the DNV recommended annual probability of failure and for maximizing system integrity as well as for a designated failure mode in which the anchor chains are the first components to fail in the system. 相似文献
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Donna J. Nickerson-Tietze 《Coastal management》2013,41(1):65-74
Fishing communities, the Government of Thailand Department of Fisheries, local nongovermnental organizations, universities, the Food and Agriculture Organization of the United Nations (FAO), and FAO's Bay of Bengal Program have undertaken a partnership in management of Phang-nga Bay's coastal resources. It is the first project of its kind in Thailand, and although still in the early stages, offers insights that may contribute to our knowledge of how we can improve our management of coastal resources, including the importance of (1) building relationships within the governance process; (2) combining education, enforcement, and economic incentives to achieve compliance; (3) implementing solutions early; and (4) government support of community-based decisions. These insights reinforce trends emerging in other coastal management projects in the Asian region. 相似文献
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文章详细分析了单相VSR型PWM整流器的整流原理,建立了电流内环,电压外环的单相VSR型PWM整流控制器的数学模型和逻辑框图。在MATLAB/Simulink软件环境中进行了仿真,分析了模型的可行性。 相似文献