摘 要

随着造船工业的发展，曲轴随着柴油机载荷的加重，工作条件变得越来越恶劣，在这一认知上我们可以得到，研究船舶柴油机曲轴动力学特性，从而得到曲轴振型频率和振型表现对改善设计有一定的积极作用，通过计算出曲轴的扭转应力，也会便于我们对于船舶柴油机曲轴的强度进行研究，当然，在工作过程中，曲轴也会受到突变的扭转振动影响，从而最终导致曲轴疲劳断裂。因此，通过仿真分析等方法进行“船舶柴油机曲轴动力学特性计算分析”研究具有一定的工程应用价值。

本文在虚拟样机技术的基础上，采用了有限元法和多体动力学相结和的仿真分析方法。本文将ANSYS和ADAMS两个软件作为分析的基本工具，在一定理论基础上，根据不同工况下和不同的作用条件下分析船舶柴油机曲轴的动力学特性和扭曲振动特性。为今后的曲轴设计和校核提供了一定程度上的指导意义。

关键词：曲轴；动力学；有限元；仿真

Summary

With the development of the shipbuilding industry, the working conditions of crankshafts are getting worse and worse as the load of diesel engines becomes heavier. Based on this knowledge, we can obtain and study the dynamic characteristics of crankshafts of marine diesel engines to obtain the vibration frequency and vibration of crankshafts. The type performance has a certain positive effect on improving the design. By calculating the torsional stress of the crankshaft, it will also be convenient for us to study the strength of the marine diesel crankshaft. Of course, during the work process, the crankshaft will also be affected by sudden torsional vibrations, Eventually, the crankshaft will fatigue and break. Therefore, the research on "the calculation and analysis of the dynamic characteristics of the marine diesel crankshaft" through simulation analysis and other methods has certain engineering application value.

In this paper, based on the virtual prototype technology, the finite element method and multi-body dynamics combined simulation analysis method are used. In this paper, the two software ANSYS and ADAMS are used as the basic tools for analysis. On the basis of a certain theory, the dynamic characteristics and torsional vibration characteristics of the marine diesel crankshaft are analyzed under different working conditions and different operating conditions. It provides a certain degree of guidance for the design and verification of the crankshaft in the future.

Key words：Crankshaft, dynamics, finite element, simulation

目 录

第1章 绪论 1

1.1 课题背景与意义 1

1.2 柴油机国内外发展现状 1

1.3 本文研究目的、方法及意义 2

1.4 本章小结 3

第2章 基础理论的阐述 4

2.1 有限元理论的介绍 4

2.1.1数值模拟技术的简介 ....4

2.1.2有限元法.................................................................................................................4

2.1.3有限元求解相关问题的步骤.................................................................................4

2.1.4有限元法相关软件的分析.....................................................................................5

2.2多体运动学基本理论 5

2.2.1.多刚体系统动力学 5

2.2.2多刚体动力学的建模方法和计算原理. 5

2.2.3子结构法 7

2.2.4多体运动学软件的简介.........................................................................................7

2.3柴油机曲轴动力学仿真分析的基础理论........................................................................7

2.3.1曲柄-连杆机构的运动学........................................................................................7

2.3.2曲柄-连杆机构的动力学........................................................................................8

2.4本章小结............................................................................................................................9

第3章曲轴有限元模型建立步骤及模态分析方法....................................................................11

3.1曲轴有限元模型建立的准备工作..................................................................................11

3.2曲轴有限元模型的建立过程……..................................................................................12

3.2.1有限元预处理节…...............................................................................................12

3.2.1.1选择单元类型……...............................................................................12

3.2.1.2有限元的网络划分……........................................................................12

3.2.1.3节点定义方法和单元定义方法……....................................................12

3.2.2有限元模型的建立...............................................................................................12

3.3模态分析的主体思想......................................................................................................13

3.4模态分析的结果及变现..................................................................................................14

3.4.1各阶固有频率.......................................................................................................14

3.4.2各阶振型图的比较...............................................................................................14

3.5本章小结..........................................................................................................................19

第4章 曲轴动力学仿真分析......................................................................................................20

4.1船舶柴油机曲轴应力分析..............................................................................................20

4.2船舶柴油机曲轴动力学仿真模型的建立......................................................................21

4.3多体动力学仿真计算结果的分析..................................................................................21

4.4本章小结..........................................................................................................................22

第5章 结论与展望......................................................................................................................23

5.1总结..................................................................................................................................23

5.2展望..................................................................................................................................23