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机械结合面参数识别及其装配性能预测
Parameter Identification of Mechanical Interfaces and Prediction of Machine’s Assemble Property
【作者】 王智渊;
【导师】 姚运萍;
【作者基本信息】 兰州理工大学 , 机械制造及其自动化, 2010, 硕士
【摘要】 高档数控机床与基础制造装备是衡量一个国家制造业现代化水平的重要标志。我国现阶段的机床设计水平较之国外先进国家仍有很大差距。为获得满意的定型产品,往往要反复经过“设计-试制-试验-修改”的过程。将结合面动静态参数引入系统整机建模过程可以有效提高在零物理样机情况下对机床动态特性的预测能力。本文以分形理论和结合面微观运动机理为核心,采用理论推导结合案例分析的方法,研究结合面参数的建模问题,并对其在装配模型动态分析中的影响进行讨论。本文从建立结合面接触刚度模型和结合面接触阻尼模型两个方面入手,以数控机床工作台装配模型为工程对象,具体完成了以下工作:首先,针对传统接触理论模型所描述粗糙表面间接触性质不具有客观唯一性和确定性的缺陷,研究基于分形理论的粗糙表面特征模型及其数学表征WM函数,分析总结了MB接触分形模型参数对结合面法向刚度和切向刚度的影响规律;其次,根据国内外学者在结合面接触阻尼参数识别方面主要存在依赖于结构质量矩阵和传递函数矩阵的问题,提出了从结合面接触时微凸体变形耗能这个角度对结合面接触阻尼进行研究。以各类机械中最为常见的螺栓连接为例,修正了能量损失与载荷幅值之间的数学关系,并应用于伊万模型阻尼参数的识别;最后,基于模态参数识别理论及有限元分析方法,选用ABAQUS作为分析工具,在三种不同的结合面参数设置情况下对数控机床工作台模型情况进行有限元分析,分析了结合面参数对机床装配性能的影响。本文通过对结合面微观形貌特征和运动机理的研究,丰富了分形理论和微凸体变形能耗理论的应用,建立了基于分形理论的结合面接触刚度模型和基于能量观点的结合面接触阻尼模型,为机械系统仿真分析中结合面参数的确定提供了理论支持,提高了产品设计开发的效率。
【Abstract】 Advanced Numerical Control Machine and Fundamental Manufacturing Equipments is the important mark that judging the manufacturing modernization level of a country. Our country’s present level of machine design has a big gap with advanced countries. In order to obtain the satisfactory final product, which must through an iterative progress of“Design-Experiment Product-Improved-Design”. Bringing the static and dynamic parameters of interfaces into machine’s computer model is an effective method that could improve the prediction of machine tool’s dynamic characteristics without a physics model. The thesis, taking fractal theory and micro motion mechanics of interfaces as the core, researched the theory model building of interfaces based on theoretical derivation and analysis of concret example. Meanwhile, discuss its affection on the dynamic analysis of assemble model.The following work was completed based on building the stiffness and damp parameter model of interfaces, taking workbench of Numerical Control Machine as object of study. Firstly, aim at the flaw that the traditional contact theory model describes the contact property of rough surface is not objective uniqueness and certainty, research the rough surface character model based on Fractal Theory and its mathematics expression WM function, concluded the influencing regularities of MB contact fractal model affects on tangential stiffness and normal stiffness of interfaces. Secondly, point at the problem that other researcher’s work mainly depend on mass matrix of mechanical structure and the transfer function of correlation parts, proposed the idea that research interface damp through energy dissipation of micro convex body’s deformation when contact occurred. Take the bolt joint which is common in many types of mechanical equipments as an example, amending the relation between energy dissipation and magnitude of load. Then apply it on the identification of Iwan Model’s parameters. At last, according to model parameters identification theory and finite element analysis methods, choose the ABAQUS as analysis software to analyze Numerical Control Machine’s workbench under three different parameters configuration situation, discuss the affects which interfaces parameters act on the performance of assembled machine.The research on micro feature and micro motion mechanics of interfaces enriched the content and engineering applications of fractal theory and energy dissipation of micro convex body’s deformation theory. Building the stiffness model of interfaces based on fractal theory and damp parameter model of interfaces based on energy dissipation, support the determining of interfaces parameter in mechanical system simulation analysis theortically, which make the design and development of product more effective.
【Key words】 Interfaces Stiffness; Interfaces Damp; Fractal Model; Energy Dissipation; Finite Element Analysis;