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超大型原油船(VLCC)是一个国家非常重要的战略船舶,由于我国在VLCC船舶设计和制造方面起步较晚,与世界先进水平还有一定的差距。VLCC船舶的振动问题一直是船舶工业领域需要解决的重点,由于VLCC船舶的上层建筑质量大、体积大,与船舶产生的共振可能会引起严重的事故。本文针对这一问题,分别对VLCC和甲板上层建筑进行振动特性分析,重点研究了VLCC上层甲板的固有频率和振动变形,最后基于Ansys有限元仿真软件,对VLCC船舶的上层建筑进行振动特性仿真。 相似文献
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文章针对某船主机燃油供给管系振动问题,介绍了开展减振工程实践之初,利用仿真计算软件对改造措施的优化仿真计算分析及其结果,并结合改造工程实践对改造后振动综合治理效果进行了测试验证,结果表明改造措施有效,管系降振效果较为明显,为更深入开展船舶动力输流管系振动治理研究提供了实例参考. 相似文献
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船舶电机的轴系不仅起到传递转距和功率的作用,也起到动力系统调速的作用,是船舶动力系统的关键装置。由于船舶电机的轴系在正常运行过程中受到外界激励作用,会产生受迫振动和扭转振动等多种振动形式,影响电机轴系的工作稳定性,甚至造成结构出现疲劳破坏。针对这一问题。本文通过建立船舶轴系的多体动力学模型,结合有限元仿真软件Ansys对电机轴系的扭转振动进行仿真分析,仿真过程包括有限元模型的建立、边界条件和约束条件的施加、扭转振动的求解以及后处理等环节。 相似文献
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液力耦合器是船舶动力系统的重要功能元件,在船舶发动机的空载启动、多机并车等运行状况下能够发挥重要的作用。液力耦合器需要传递较大的转速和功率,其工作稳定性和噪声振动特性对于船舶有重要意义。本文首先介绍液力耦合器的基本组成与工作参数,结合液力耦合器的功能特点设计了一种液压控制回路。详细介绍了液压控制回路的各个结构参数,并结合Ansys FLuent仿真平台进行了液压控制回路的液体流速仿真,可以有效提高液力耦合器的设计水平。 相似文献
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上层建筑振动是影响船舶整体稳定性的主要因素,所以对其进行有效分析具有重要的现实意义。本次针对以往基于经验公式建立软件程序来计算上层建筑振动频率,存在精度不足的问题,提出一种有限元分析方法。利用有限元分析法进行船舶上层建筑振动性能研究主要分为两部分:先是选定船舶参数,利用利用Ansys软件进行上层结构有限元建模;后是对该模型进行求解,计算船舶上层建筑振动频率,实现振动性能研究,并与基于经验公式软件程序法进行对比,得出有限元分析法精度更高,结果更接近真实值。 相似文献
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舰船浮筏减振特性研究 总被引:2,自引:2,他引:0
舰船机械设备在运转时会引起船舶结构的强迫振动,造成船舶结构的损坏,降低船载精密设备的工作精度。因此,舰船隔振技术一直是船舶工业的研究热点。舰船浮筏是一种新型的弹性减振器,它利用弹性阻尼元件将船载机械设备与船体分离,使船载设备的振动无法直接传递到船体,并通过控制和吸收振动源的弹性波达到减振的目的。本文系统分析了舰船浮筏减振器的结构与原理,建立了舰船浮筏的有限元模型,对舰船浮筏的减振特性进行基于Ansys软件平台的仿真研究,并进行了舰船浮筏的相关参数优化。 相似文献
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Ingo Drummen Gaute Storhaug Torgeir Moan 《Journal of Marine Science and Technology》2008,13(4):428-445
Fatigue cracks have been known to occur in welded ships for several decades. For large ocean-going ships wave-induced vibrations
can, depending on trade and design, cause up to 50% of the fatigue damage. The vibrations may be due to springing and whipping
effects. In this paper, we address the fatigue damage caused by wave-induced vibrations in a containership of newer design
trading in the North Atlantic. The fatigue damage was obtained both experimentally and numerically. The experimental results
were found from tests performed with a flexible model of the ship, while the numerical predictions were done using nonlinear
hydroelastic strip theory. The measurements showed that the wave-induced vibrations contributed approximately 40% of the total
fatigue damage. The numerical method predicted the wave frequency damage well, but was found to overestimate the total fatigue
damage by 50%. This was mainly due to an overprediction of the wave-induced vibrations. The discrepancy is partly related
to three-dimensional (3D) effects which are not included in the two-dimensional (2D) slamming calculation, and partly to an
overprediction of the springing contribution. Moreover, the numerical method does not account for the steady wave due to forward
speed. By using a simplified approach we show that high-frequency damage can be significantly reduced by including the steady
wave for the relevant vessel, implying better agreement with the experimental results. 相似文献
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采用单片机89C51为核心设计船舶保安警报系统,通过RS-232串口和船载GPS连接,利用C程序对数据进行处理,实现GPS信号的采集处理及通过船舶C站对报警信号的发送。 相似文献
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In this paper, numerical simulations of vortex-induced vibrations in a vertical top-tension riser with a length-to-diameter ratio of 500 using our in-house code viv-FOAM-SJTU are presented. The time-dependent hydrodynamic forces on two-dimensional strips are obtained by solving the Navier-Stokes equations, which are, in turn, integrated into a finite-element structural model to obtain the riser deflections. The riser is discretized into 80 elements with its two ends set as pinned and 20 strips are located equidistant along the risers. Flow and structure are coupled by hydrodynamic forces and structural displacements. In order to study the effects of the shear rate, of the current profiles on the vortex-induced vibrations in the riser, vibrations, with varying shear rates, in both the in-line and cross-flow directions, are simulated. In addition to the time domain analysis, spectral analysis was conducted in both the temporal and spatial domains. Multi-mode vibration characteristics were observed in the riser. The relationship between dominant vibration mode number and the shear rate of current profiles is discussed. In general, the overall vibrations in the riser pipe include contributions from several modes and each mode persists over a range of shear rates. Moreover, the results suggest that with a larger shear rate the position of the maximum in-line time-averaged displacement will move closer to the end where the largest velocity is located. 相似文献
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本文介绍了用于特征值计算的Lanczos法的基本理论,以大连教学实习船为例,利用MSC软件建立了该船的全船细网格模型。分析了该船的低阶整体自由振动和上层建筑局部自由振动,总结了该船的振动特性。 相似文献
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航运国际化的发展和航运人才要求的提高,对航海专业教师的要求也越来越高。本文从三个方面进行分析,阐述了航海专业教师上船任职锻炼的必要性。 相似文献
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细长海洋结构物涡激振动研究综述 总被引:5,自引:0,他引:5
随着世界范围内深海石油开采的需要,近年来关于海洋结构物涡激振动的研究越来越受到重视.虽然此问题在数值模拟和实验方面都已取得了一定的进展,但是还有许多问题尚待解决.同时,新型海洋结构物的引入给涡激振动的预报方法和抑振手段提出了新的挑战.因此,细长海洋结构物的涡激振动仍将是未来几年里备受关注的研究课题.本文在介绍有关涡激振动基本概念和理论背景的基础上,总结了近年来关于以深水立管为代表的海洋结构物涡激振动的研究与进展,包括对现有涡激振动分析工具的分类与评估;对柱体及海洋结构物涡激振动的实验研究;对深水立管与涡激振动相关的疲劳评估准则的研究;海洋结构物的横向、流向及轴向涡激振动的耦合作用研究;关于海洋结构物涡激振动的抑振措施和设备的理论及实验研究.本文着重介绍了计算流体力学方法在海洋结构物涡激振动研究中的应用和进展.最后,对海洋结构物涡激振动相关的研究热点的现状进行了总结并对今后工作提出了展望. 相似文献