300吨级渔政船全船振动特性预报

发布时间：2018-11-18 13:56

【摘要】：船舶在正常的营运过程中,会受到螺旋桨、船舶主机等激励的作用。这些激励将引发船舶发生不同程度的振动甚至是有害振动,由此可能导致船舶结构产生疲劳破坏,影响到船舶设备正常使用,以及工作人员的效率甚至身体健康。因此,在船舶设计的不同阶段必须预报船舶的振动特性,提出存在的问题以及解决措施,避免发生共振,使船舶结构达到低振动、低噪声的要求。本文以300吨级渔政船为研究对象,通过有限元软件ANSYS对其振动特性进行研究。主要内容如下： (1)计算并分析目标船的主要激励源,包括主机激励和螺旋桨激励。V型柴油机可以看成两个直列式柴油机进行不平衡力和力矩的计算,然后按照气缸夹角进行合成即可。 (2)全船总振动特性计算分析。首先在Pro/Engineer中建立目标船的三维几何模型,然后用专业网格划分软件HyperMesh进行网格划分得到有限元离散模型,相关属性和附连水质量施加完成后导入ANSYS进行模态分析,得到总振动的前6阶固有频率和振型。然后与主要激励频率进行对比,对比结果表明该船满足频率储备要求,不会发生整船共振现象。 (3)目标船强迫振动响应计算分析。确定船体阻尼、位移边界条件以及载荷的施加方式后进行瞬态动力学分析,得到速度和加速度的时域特性,结合评价基准的特点进行傅立叶变换得到参数的频域特性。无论是单机工作还是双机工作,各评价区域的速度峰值均小于下限4mm/s,处于振动轻微区域,该船振动特性良好。单机工作下和双机工作下的振动最大区域都在机舱处所,速度峰值分别为0.7mm/s和1.7mm/s.表明机舱是全船振动较为恶劣的地方,应给予充分的关注。
[Abstract]:In the normal operation process, ship will be driven by propeller, ship main engine and so on. These incentives will lead to different degrees of vibration and even harmful vibration of the ship, which may lead to fatigue damage of the ship structure, which will affect the normal use of ship equipment, as well as the efficiency of the staff and even the health of the staff. Therefore, in different stages of ship design, the vibration characteristics of the ship must be predicted, and the existing problems and solutions should be put forward to avoid resonance and to make the ship structure meet the requirements of low vibration and low noise. In this paper, the vibration characteristics of 300 dwt fishery administration ship are studied by finite element software ANSYS. The main contents are as follows: (1) the main excitation sources of the target ship are calculated and analyzed, including main engine excitation and propeller excitation. V diesel engine can be regarded as two linear diesel engines to calculate the unbalanced force and torque. Then according to the cylinder angle synthesis can be. (2) calculation and analysis of the total vibration characteristics of the whole ship. Firstly, the 3D geometric model of the target ship is established in Pro/Engineer, and then the finite element discrete model is obtained by using the specialized meshing software HyperMesh. After the relevant attributes and the attached water quality are applied, the modal analysis is carried out by ANSYS. The first six natural frequencies and modes of total vibration are obtained. Then compared with the main excitation frequency, the comparison results show that the ship meets the requirement of frequency reserve and does not have the whole ship resonance phenomenon. (3) calculation and analysis of forced vibration response of target ship. After determining the hull damping, displacement boundary conditions and load application mode, the transient dynamics analysis is carried out, and the time-domain characteristics of velocity and acceleration are obtained, and the frequency-domain characteristics of parameters are obtained by Fourier transform combined with the characteristics of evaluation datum. The peak velocity of each evaluation area is less than the lower limit of 4 mm / s, and the ship is in a slight vibration region, and the vibration characteristics of the ship are good. The maximum vibration area under single and dual operation is in the cabin, and the peak velocities are 0.7mm/s and 1.7 mm / s, respectively. It shows that the engine room is the place where the vibration of the whole ship is relatively bad, which should be given sufficient attention.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U661.44;U674.2

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