摘 要
以往對船舶推進(jìn)系統(tǒng)的研究中，通常以軸系本身為主，主機(jī)與軸系作為單獨(dú)對象進(jìn)行分析，并未考慮主機(jī)、軸系、螺旋槳之間的相互作用與影響。本文以某船推進(jìn)系統(tǒng)為研究對象，應(yīng)用有限元和子結(jié)構(gòu)縮減法，建立曲軸、軸系、螺旋槳以及各簡易軸承座等體單元，通過非線性聯(lián)接單元將各體單元連接，建立推進(jìn)系統(tǒng)非線性多體動力學(xué)模型。在考慮主機(jī)額定工況燃?xì)鈮毫吐菪龢ふ窳Φ葪l件下進(jìn)行了計(jì)算，分析了曲軸、軸系、螺旋槳的受力與位移，以及螺旋槳載荷的影響，其中，軸系部分重點(diǎn)分析了艉軸后軸承處軸系的受力與位移情況。結(jié)果表明：
1）與未考慮螺旋槳載荷時(shí)相比，受螺旋槳載荷影響，曲軸輸出端軸向位移波動加劇，相對角位移最大值增加了66%；2）兩種情況下曲軸各軸頸豎直水平方向受力與位移的幅值與變化趨勢基本一致，但螺旋槳載荷引起了其工作循環(huán)內(nèi)的微小跳動，輸出端尤為明顯。因此，在進(jìn)行曲軸軸承潤滑特性分析時(shí)，應(yīng)該考慮螺旋槳外部載荷的影響，使得模型更符合實(shí)際情況。
3）受螺旋槳載荷的影響，艉軸后軸承位置軸系受力與位移隨曲柄轉(zhuǎn)角呈周期性變化，受力主要集中在兩端，靠近螺旋槳一端約是另一端的5倍，且豎直方向明顯大于水平方向。4）螺旋槳豎直方向位移基本為負(fù)，水平方向正負(fù)交替且幅值相當(dāng)，螺旋槳慣性力矩對軸系扭矩產(chǎn)生顯著影響，其幅值與激振扭矩幅值相當(dāng)。5）計(jì)算得螺旋槳相對角位移最大值為0.087rad；豎直向下位移最大值為2.86mm；軸向位移最大值為1.18mm，向主機(jī)方向偏移。為提高船舶推進(jìn)系統(tǒng)可靠性及其優(yōu)化設(shè)計(jì)提供了重要參考。

關(guān)鍵詞：船舶推進(jìn)系統(tǒng)，柴油機(jī)，激振力，動力學(xué)












ABSTRACT
In the dynamic investigation of propulsion shaft system formerly, main engine and shaft is analyzed separately. As a result the interaction of main engine, shaft and propeller could not be considered. In this thesis the propulsion shaft system is investigated. A multi-body dynamic model of propulsion shaft system including diesel engine, shaft, propeller and simple bearing block is established based on FE-Models and substructure technique, where different bodies are coupled by several non-linear coupling elements. The calculation is performed when combustion pressure and propeller exciting force is loaded on corresponding bodies at the state of power rating. The dynamic behavior of crankshaft, shaft and propeller is investigated within a complete engine cycle, as well as the influence of propeller exciting force to the system.
The results indicate that, as the affects of propeller exciting force, at drive end of crankshaft, the oscillation of axial displacement is intensified obviously, the relative angular displacement is increased 66%. Under different conditions, the trend and the maximum value of force and displacement of journals are consistent, but that is fluctuating tiny. So it is better to consider exterior load when analyzing the lubrication of crankshaft, for the model being more realizable. The force and displacement of shaft is analyzed, and that of propeller and shaft at rear stern bearing location is mainly analyzed. At rear stern bearing location, as influence of propeller load, the force and displacement is changed periodically along with the periodicity of exciting moment, and the value in vertical direction is bigger. The value of force at two ends is much bigger than that in middle, and the force close to propeller is about 5 times of that at the other end. The gravity and inertial moment of propeller affects dynamics obviously, the maximum value of inertial moment is almost equal to that of exciting torque, as a result the displacement in vertical direction is minus most time within an engine cycle, in horizontal direction the value alternate between plus and minus. For propeller, the maximum value of displacement in vertical direction is 2.86mm, and 1.18mm in axial direction to the engine, the maximum relative angular displacement value is 0.087radian. That provides an important reference for analyzing and improving the reliability of propulsion system and implementing its optimization.

Key words: propulsion shaft system, marine diesel, exciting force, dynamic




目 錄
摘 要 I
ABSTRACT III
第一章 緒論 1
1.1 研究背景及意義 1
1.2 國內(nèi)外研究現(xiàn)狀 1
1.2.1動力學(xué)研究方面 2
1.2.2動力學(xué)建模方面 2
1.3 研究內(nèi)容與方法 3
第二章 船舶推進(jìn)系統(tǒng)模型 5
2.1 理論基礎(chǔ) 5
2.1.1 有限元法 5
2.1.2 多體動力學(xué)基本理論 5
2.2 船舶推進(jìn)系統(tǒng)有限元模型 7
2.2.1 曲軸 7
2.2.2 軸系 9
2.2.3 螺旋槳 11
2.2.4 軸承座 11
2.3 船舶推進(jìn)系統(tǒng)多體動力學(xué)模型 13
2.3.1 推進(jìn)系統(tǒng)組成及基本參數(shù) 14
2.3.2 定義體單元 16
2.3.3 定義非線性聯(lián)接單元 17
2.3.4 推進(jìn)系統(tǒng)多體動力學(xué)模型 22
2.4 本章小結(jié) 23
第三章 計(jì)算外部激振力 25
3.1 氣缸燃?xì)鈮毫?25
3.2 計(jì)算螺旋槳激振力 26
3.2.1 螺旋槳扭轉(zhuǎn)激振力 27
3.2.2 螺旋槳軸向激振力 28
3.2.3 螺旋槳彎曲激振力 29
3.3 本章小結(jié) 30
第四章 柴油主機(jī)動力學(xué)分析 31
4.1 曲軸全局運(yùn)動分析 31
4.2 曲軸系動力學(xué)分析 34
4.2.1 活塞受力分析 34
4.2.2 曲軸受力分析 34
4.2.3 曲軸輸出端分析 36
4.2.4 軸心軌跡分析 38
4.3 本章小結(jié) 41
第五章 推進(jìn)軸系動力學(xué)分析 43
5.1 軸系分析 43
5.2 螺旋槳 46
5.3 本章小結(jié) 48
第六章 結(jié)論與展望 49-br..