4125A 型柴油机曲轴结构有限元模态分析

毕业设计(论文)

课题名称 4125A 型柴油机曲轴结构有限元模态分析

学生姓名

学号 1141103044 系、年级专业机械与能源工程系

指导教师

教师职称副教授

2015年 5 月30 日

摘要

曲轴是发动机的主要受力构件之一，也是发动机重要的构成部件，其尺寸和参数决定着发动机整体构成以及其性能和机构尺寸与发动机的寿命和可靠性。曲轴的工作环境决定曲轴受力比较复杂，曲轴不仅要受压力，惯性力还要受弯矩，由于曲轴受力比较复杂，所以在对曲轴进行设计时要求也比较高。为了避免曲轴在工作时发生共振，导致曲轴失效需要对曲轴进行模态分析，这样可以求出曲轴共振频率，以及曲轴在工作时的振型及其载荷的变化规律，从而在设计时可以规避共振对曲轴损坏，这对提高曲轴的寿命和可靠性是很有效的。

该课题研究的是4125A型柴油机曲轴有限元分析。通过ANSYS有限元分析软件对此柴油机的曲轴进行建模然后进行静力学分析和模态分析，由此可以了解曲轴在工作时所受的工作载荷，以及工作危险截面和曲轴工作的共振频率、振型。这样可以了解曲轴的实际工作情况，就可以在进行曲轴设计时合理的安排曲轴的结构和尺寸，在设计时采取各种措施提高曲轴危险截面的强度更好的规避曲轴的共振区间，以提高曲轴设计和工作的可靠性，减少开发周期，从而提高柴油机曲轴的设计质量。

1.运用ANSYS14.0建立曲轴的三维实体模型以及确定网格单元的相关参数

类型。

2.先在ANSYS中确定网格划分精度和网格划分密度等，然后对所建立的三

维实体模型进行网格划分，限制模型的自由度以及对其进行加载力。

3.用ANSYS中的相关模块对所建立的三维实体模型进行静力学分析和模

分析，就可以的得到相应的结果

关键字：曲轴；模态分析；有限元分析

ABSTRACT

Crankshaft is one of the main components of the engine and the important engine of the stress components, the size and parameters determines engine overall structure, performance and organization size and engine life and reliability. Crankshaft working environment decided to entertain the crankshaft complex, the crankshaft must not only pressure, inertia force but also by the moment, because the crankshaft accept more complex, so in the design of the crankshaft requirements are relatively high, in order to avoid showing off the crankshaft at work when resonance occurs, resulting in failure of the crankshaft to the modal analysis of the crankshaft, so that we can find the resonance frequency of the crankshaft, and crankshaft at work and the mode of vibration load variation, which in the design can avoid resonance of crankshaft damage, which to improve the service life and the reliability of the crankshaft isvery effective.

The paper is on the study of 4125A diesel engine crankshaft finite element analysis. Through the finite element analysis software ANSYS in this regard diesel engine crankshaft modeling and static analysis and modal analysis, then we can know the work load of crankshaft, and dangerous work section and crankshaft of resonance frequency, vibration mode. Thus the actual working condition of crankshaft can be in for the crankshaft design reasonable arrangement of the crankshaft structure and size to improve the crankshaft design and working reliability, At design time, take various measures to improve the strength of crankshaft resonance interval to avoid the dangerous section of the crankshaft，reduce the development cycle，So as to improve the design quality of the crankshaft of the diesel engine.

(1)The use of ANSYS14.0 to build three-dimensional model of the crankshaft and the parameter determination unit and grid type.

(2)first in ANSYS determine the meshing accuracy and mesh density, then carries on the grid division of the three-dimensional solid model established, the restricted model degrees of freedom and the for loading.

(3)Using ANSYS module in 3D model based on the static analysis and modal analysis.