多源激励作用下大型船舶推进轴系的扭转-横向耦合振动机理研究

Large ships are the important support for the state to implement the strategy of maritime power and manufacturing power. As a core part of marine propulsion system, the coupled vibration mechanism of propulsion shaft in complex and changeable operation environment is not fully revealed, which seriously affects the stability and reliability of ships in navigation. This project focus on the propulsion shaft of large ships to investigate the coupled torsional-transverse mechanism and vibration characteristics of shaft under multisource excitations. The effects of propeller thrust, main engine torque and hull deformation on the vibration of the shaft are explained respectively, and a dynamic model of the propulsion shaft for large ships under multisource excitations is thus established. A more accurate and applicable solution method for the coupled torsional-transverse vibrations of multi-segment shaft is proposed on the basis of reduced order method and lumped-mass method. The vibration responses of different eccentricity of cross sections in time and frequency domain are solved to reveal the mechanism of coupled torsional-transverse vibrations of the shaft. The design method for propulsion shaft is modified based on the adjustment of the unbalance quantity, and the optimized design for the structural size of the shaft is thus realized. The successful development of this project can provide reliable calculation method for the coupled vibrations of large ship propulsion shaft. It has important scientific significance for enriching and developing the ship vibration theory.

大型船舶是国家实施海洋强国和制造强国战略的重要支撑。推进轴系作为船舶动力系统的核心部分，在复杂多变运行环境下的耦合振动机理还未得到充分的揭示，严重影响船舶航行的稳定性和可靠性。本项目以大型船舶的推进轴系为研究对象，对多源激励作用下的轴系扭转-横向耦合机理及其振动特性进行系统深入的研究。分别阐明螺旋桨、主机和船体变形激励对轴系振动的作用规律，构建多源激励作用下大型船舶推进轴系的动力学模型。基于降阶法与集中质量法，提出一种多段轴结构的轴系耦合振动计算方法，求解该模型在不同截面偏心距条件下的时频域响应，揭示推进轴系扭转-横向耦合振动机理。通过对不平衡量的调整，完善船舶轴系的设计方法，实现推进轴系结构尺寸的优化设计。本项目的顺利开展，可为大型船舶推进轴系耦合振动分析提供可靠的计算方法，对丰富和发展船舶振动理论具有重要的科学意义。

本项目研究船舶推进轴系在考虑多源激励条件下的弯扭耦合振动问题中涉及到的诸多理论和技术问题，阐述弯扭耦合振动对轴系优化设计与校中的实际需求与工程应用，以提高轴系在多源激励条件下的运行可靠性，进而改善船舶在复杂海洋条件下的航行安全性。项目系统分析了船舶推进轴系在轴承摩擦、轴线失中以及截面偏心等影响因素下的作用规律，分别建立了轴系-轴承耦合动力学、轴系扭转-纵向以及扭转-横向耦合振动的理论模型，深入探究了轴系运转过程中转速、阻尼以及外部载荷对耦合振动影响规律，初步揭示了轴系多向耦合振动的耦合机理，提供了推进轴系的减小摩擦磨损、结构尺寸优化的计算方法。建立了轴系-轴承耦合动力学，系统分析了船舶推进轴系在轴承船体变形和轴承支撑等影响因素下的振动特性，提供了推进轴系的减小摩擦磨损、结构尺寸优化的计算方法。

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