齿轮压缩机螺栓法兰连接的静—动力学数值模拟研究

发布时间：2018-03-10 23:04

本文选题：螺栓法兰连接　切入点：接触问题　出处：《昆明理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：螺栓法兰连接广泛应用于航空航天、石油化工、机械工程等工业结构中。压缩机通常是在动荷载作用下运行,其螺栓法兰连接结构的力学特征是属于典型的状态非线性问题,很多时候伴随有几何非线性和材料非线性,使得非线性程度变得更加复杂。大多数接触问题难以用经典的数学和力学方法解决,随着以有限单元法为核心的现代计算机辅助工程技术的发展,使有限元数值模拟技术得到广泛应用。连接结构的多重非线性特性对结构静、动力学性能有着极大的影响,因此,本文深入分析螺栓法兰连接结构的非线性特征,并将其引入到整体结构的静、动力学建模与数值模拟分析中。采用了ANSYS Workbench对齿轮压缩机的螺栓法兰连接结构进行静强度与连接状态校核以及整体结构模态分析。本文的主要工作为：1.详细介绍接触基本理论,主要分析了罚函数法与增广拉格朗日乘子法这两类接触算法,并对影响计算收敛性的重要参数接触刚度因子进行了详细讨论。2.在螺栓法兰连接非线性特性分析的基础上,通过对比不同的有限元建模方法,给出了该结构合理的建模方法,即三维实体单元建模。对比不同预紧力施加的数值模拟方法,得出采用预紧力单元法能较精确、有效地模拟预紧力的施加。3.对螺栓法兰连接结构进行了静力学分析,主要分析了影响计算收敛性的几个主要因素：接触对的建立、接触类型和接触算法的选取、以及罚刚度大小。重点分析接触刚度对计算收敛性的影响,通过试算法得到合理的罚刚度值,并进行法兰连接状态评估以及螺栓强度校核。4.对螺栓法兰连接结构进行整体模态分析,把连接面的接触非线性特征(边界条件非线性)引入到整体模态分析中,并对该连接结构采用三维实体建模。对比不考虑连接面状态非线性特性(即直接将连接面固连)与考虑连接面状态非线性特性两种建模方法的计算结果,以及螺栓预紧力对整体结构模态的影响。
[Abstract]:Bolt flange connections are widely used in aerospace, petrochemical, mechanical engineering and other industrial structures. The mechanical characteristics of bolted flange connections are typical state nonlinear problems. In many cases, the degree of nonlinearity is complicated by geometric nonlinearity and material nonlinearity. Most contact problems are difficult to solve by classical mathematical and mechanical methods. With the development of modern computer aided engineering technology with the finite element method as the core, finite element numerical simulation technology has been widely used. The multiplex nonlinear characteristics of the connection structure have great influence on the static and dynamic performance of the structure. In this paper, the nonlinear characteristics of bolted flange connection structure are deeply analyzed and introduced into the static structure of the whole structure. In dynamic modeling and numerical simulation analysis, the static strength and connection state of bolted flange connection structure of gear compressor are checked by ANSYS Workbench and the modal analysis of the whole structure is carried out. The main work of this paper is: 1. The basic theory of contact is introduced in detail. In this paper, two contact algorithms, penalty function method and augmented Lagrangian multiplier method, are mainly analyzed, and the contact stiffness factors, which affect the convergence of calculation, are discussed in detail. 2. Based on the analysis of nonlinear characteristics of bolt flange connection, By comparing different finite element modeling methods, the reasonable modeling method of the structure, that is, 3D solid element modeling, is given. Compared with the numerical simulation methods applied by different pretightening forces, it is concluded that the pretightening force element method can be used more accurately. The static analysis of bolted flange connection structure is carried out, and several main factors affecting the convergence of calculation are analyzed, such as the establishment of contact pair, the selection of contact type and contact algorithm. The influence of contact stiffness on the convergence of calculation is analyzed, and the reasonable penalty stiffness is obtained by trial algorithm. The overall modal analysis of bolted flange connection structure is carried out, and the nonlinear contact characteristics (boundary condition nonlinearity) of the connection surface are introduced into the overall modal analysis. Three dimensional solid modeling is used to model the connection structure. The results of two modeling methods, which do not consider the nonlinear characteristics of the connection surface state (that is, connect the connection surface directly) and consider the nonlinear characteristics of the connection surface state, are compared. And the effect of bolt preload on the mode of the whole structure.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH45;TH131.3

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