In recently constructed vessels, minimization of engine room volume is required to maximize the volume of cargo to be shipped. Therefore, the main engine and the stern bulkhead mounted on the ship are installed as far as possible in the aftward direction. As a result, the length of the propeller shaft is reduced, along with the stern tube bearing span used to support it. In this case, the shaft flexibility is reduced, the reaction influence number is increased, and the point load of each bearing is easily influenced by change in displacement. Because the point load of each bearing is susceptible to hull deformation and thermal expansion, it is difficult to adjust the shaft arrangement and the bearing load change after large adjustment of the shaft arrangement. Therefore, in the past, the bearing was arranged to support the propeller shaft with two forward and afterward stern tube bearings. However, when the main engine and the stern bulkhead are installed as far aftward as possible to minimize the volume of the engine room, it is necessary to provide shaft flexibility by removing the forward stern tube bearing. As a result, the resonance revolution of the propeller blades during whirling vibration of the propulsion shafting system falls within the range of normal operating revolutions. This means that abnormal wear of the stern tube bearing, damage to the stern tube sealing device, and hull structure vibration may occur due to the whirling vibration. In this paper, the characteristics of shafting alignment and whirling vibration of a ship supporting a propeller shaft with double and single stern tube bearings are compared. Moreover, the changes in shaft flexibility and the characteristics of the whirling vibration of a corresponding shafting system in a 50 K-DWT petroleum product tanker were explored by applying a single stern tube bearing. In addition, the shafting alignment and whirling vibration are determined according to the installation position of the intermediate shaft bearing. A method is suggested for selecting the optimal shafting arrangement by which to secure the shaft flexibility of a ship to which a single stern tube bearing is applied, and to avoid resonance from the whirling vibration.

中文翻译：

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单尾管轴承船舶推进轴系设计与分析

在最近建造的船舶中，需要最小化机舱容积以最大化要运输的货物容积。因此，安装在船上的主机和艉舱壁尽量向后安装。结果，传动轴的长度以及用于支撑它的艉轴管轴承跨距都减少了。在这种情况下，轴的柔韧性降低，反作用影响数增加，每个轴承的点载荷容易受到位移变化的影响。由于各轴承的点载荷易受船体变形和热膨胀的影响，轴布置调整困难，轴布置调整大后轴承载荷发生变化。因此，在过去，轴承被布置为通过两个前后艉轴管轴承支撑传动轴。但是，当主机和艉舱壁安装在尽可能靠后的位置以最小化机舱体积时，需要通过拆除前艉轴管轴承来提供轴的柔韧性。因此，推进轴系发生回旋振动时螺旋桨叶片的共振转速在正常工作转速范围内。这意味着艉轴管轴承异常磨损、艉轴管密封装置损坏、船体结构可能因回旋振动而发生振动。本文比较了采用双尾管轴承和单尾管轴承支撑螺旋桨轴的船舶的轴系校中特性和回旋振动特性。此外，通过应用单个艉轴管轴承探索了 50 K-DWT 石油产品油轮中相应轴系系统的轴柔性变化和涡动振动特性。另外，轴系校中和回旋振动是根据中间轴承的安装位置确定的。提出了一种选择最佳轴系布置的方法，通过该方法可以确保采用单尾管轴承的船舶的轴柔性，并避免回旋振动引起的共振。轴系校中和回旋振动根据中间轴承的安装位置确定。提出了一种选择最佳轴系布置的方法，通过该方法可以确保采用单尾管轴承的船舶的轴柔性，并避免回旋振动引起的共振。轴系校中和回旋振动根据中间轴承的安装位置确定。提出了一种选择最佳轴系布置的方法，通过该方法可以确保采用单尾管轴承的船舶的轴柔性，并避免回旋振动引起的共振。