船舶艉部结构对尾轴振动特性影响研究

Research on Influence of Stern Structure upon Vibration Characteristic of Ship Propeller Shaft

船舶大尺度效应造成船体变形大,使船舶轴系和船体之间相互耦合、相互影响等问题十分突出。为此,建立了具有非线性油膜力作用的尾轴—油膜—艉部结构耦合系统动力学模型,推导了系统的动力学微分方程并对方程进行求解,分析了不同转速下尾轴的非线性动力学特征,总结了艉部结构系统的固有频率、参振质量、支承刚度、连接刚度对尾轴振动特性的影响。结果表明,考虑艉部结构的影响之后,尾轴—艉部结构耦合系统的振动特性发生了较大改变,耦合程度受艉部结构固有频率影响较大,尾轴最大振幅随艉部结构参振质量和支承刚度的变化而发生改变。

With the increasing scale of ship, the increasing hull deformation leading to the problem like mutually affect between the ship shafting and hull structure. Considering the influence of bearing oil-film force and nonlinear rubbing force, a ship shafting-oil film-stern structure system dynamic model is established, so as to carry out the computer numerical simulation, and the nonlinear dynamics properties of ship shafting under different rotating speeds is calculated. The dynamic behaviors of the coupling system and the vibration characteristic influenced by mass of participating in vertical vibration, supporting stiffness and connection stiffness is analyzed. It is concluded that the vibration characteristic of coupling system with influence by stern structure have been revised significantly. The extent of coupling is greatly affected by natural frequency of stern structure, and the maximum amplitude of shaft changes over mass of participating in vertical vibration and supporting stiffness.