液压挖掘机工作装置的有限元分析与参数优化

发布时间：2018-01-08 21:24

本文关键词：液压挖掘机工作装置的有限元分析与参数优化　出处：《兰州交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：液压挖掘机的工作装置是液压挖掘机各项功能的执行机构，其结构强度、固有频率等因素直接影响着液压挖掘机的工作性能和工作效率。本文以单斗反铲式液压挖掘机的工作装置为研究对象，对其进行了静强度分析、模态分析、谐响应分析与疲劳分析，并对其参数进行了优化。本文首先分析了液压挖掘机在国内外的发展现状及其前景，阐述了液压挖掘机工作装置的工况与可能出现的失效形式，并在Pro/E5.0中对单斗反铲式液压挖掘机工作装置的铲斗、斗杆和动臂三个构件建立了三维实体模型。然后，利用ANSYS Workbench14.5建立了该工作装置的有限元分析模型，，通过确定材料属性、划分网格、确定约束条件、添加约束和施加载荷，对工作装置进行了两种工况下的静强度分析，求得了铲斗、斗杆和动臂的应力云图、合位移云图及其三向分位移云图。本文继而对单斗反铲式液压挖掘机的工作装置进行了模态分析、谐响应分析与疲劳分析，得到了铲斗、斗杆和动臂的固有频率、主振型及其在两种工况下的频率响应和相位响应，同时得出了在恒幅载荷和变幅载荷作用下铲斗、斗杆和动臂的最小寿命、安全系数、疲劳敏感性、雨流矩阵及损伤矩阵等结果。为了对液压挖掘机的工作装置进行参数优化，本文对工作装置中各构件所受载荷与其最大等效应力、合位移量、寿命及损伤之间的关系进行了分析，从而为挖掘机工作装置的结构优化和形状优化提供了重要的参考依据。通过静强度分析，得知液压挖掘机的铲斗与斗杆在最大挖掘深度的工况下所受应力最大。铲斗上的最大应力发生在铲斗与斗杆连接耳板的根部，其危险的位置为铲斗液压缸与斗杆的铰接处以及斗杆与铲斗、斗杆与四连杆的铰接处。斗杆的最大应力发生在前部腹板与下翼板的连接部位和液压缸与斗杆连接的耳板根部。动臂的最大应力发生在动臂与动臂液压缸铰接点处的根部、动臂与斗杆铰接处以及斗杆液压缸与动臂的铰接处。通过模态分析，发现真正能影响工作装置的频率大多都在前三阶上。而谐响应分析表明除一些特殊点外，工作装置的稳定性均可得到保证。利用疲劳分析，得出了工作装置的最高和最低寿命循环次数和安全系数。通过对工作装置参数的优化，得到了设计点与各参数之间优化后的曲线关系、合位移响应面、最大和最小等效应力的响应面等，从中发现了参数间的最优点。
[Abstract]:The working device of hydraulic excavator is the executive mechanism of each function of hydraulic excavator, and its structural strength. Natural frequency and other factors directly affect the working performance and efficiency of hydraulic excavator. In this paper, static strength analysis and modal analysis of single bucket backhoe hydraulic excavator are carried out. Harmonic response analysis and fatigue analysis are carried out, and its parameters are optimized. This paper first analyzes the development and prospects of hydraulic excavators at home and abroad, and expounds the working conditions and possible failure forms of hydraulic excavators. Three dimensional solid models of bucket, bucket rod and arm of single bucket backhoe hydraulic excavator working device are established in Pro/E5.0. The finite element analysis model of the working device is established by using ANSYS Workbench14.5. By determining the properties of the material, dividing the mesh, determining the constraint conditions, adding constraints and applying loads. The static strength analysis of the working device under two working conditions is carried out, and the stress cloud diagram, the combined displacement cloud diagram and the three-direction displacement cloud diagram of the bucket, bucket rod and moving arm are obtained. In this paper, modal analysis, harmonic response analysis and fatigue analysis of the working device of single bucket backhoe hydraulic excavator are carried out, and the natural frequencies of bucket, bucket rod and moving arm are obtained. At the same time, the minimum life, safety factor and fatigue sensitivity of bucket, bucket rod and arm under constant amplitude load and variable amplitude load are obtained. The results of rain flow matrix and damage matrix. In order to optimize the working equipment of hydraulic excavator, the relationship between the load of each component and its maximum equivalent stress, displacement, life and damage is analyzed in this paper. Therefore, it provides an important reference for the structure optimization and shape optimization of the excavator working device. Through the static strength analysis, it is known that the maximum stress of the bucket and bucket rod is under the condition of the maximum digging depth, and the maximum stress on the bucket occurs at the root of the earplate connected to the bucket and bucket rod. The dangerous position is the hinge of the bucket hydraulic cylinder and the bucket rod and the bucket rod and bucket. Hinges of bucket rods and four-bar linkages. The maximum stress of the bucket rod occurs at the joint between the front web and the lower flange and at the root of the ear plate connected by the hydraulic cylinder and the bucket rod. The maximum stress of the arm occurs at the hinge point of the arm and the hydraulic cylinder of the arm. At the root. The hinge of the arm and the bucket rod and the hinge of the bucket rod hydraulic cylinder and the arm. Through modal analysis, it is found that most of the frequencies that can affect the working device are on the first three steps. The harmonic response analysis shows that the stability of the working device can be guaranteed except at some special points, and the fatigue analysis is used. The maximum and minimum life cycle times and safety factor of the working device are obtained. Through the optimization of the working device parameters, the optimized curve relationship between the design point and the parameters is obtained, and the displacement response surface is obtained. From the response surface of the maximum and minimum equivalent stress, the best among the parameters is found.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU621

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