机械结合面微观作用机理初探及应用
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摘要
机械结合部是机械系统中一种固有的结构形式,它在外加载荷的作用下表现出既有弹性又有阻尼的动力学特性,对系统的整体动态性能有很大的影响。机床结构中结合部的弹性和阻尼往往比结构本身的弹性和阻尼还大,所以结合部对机床的整体动态性能有着重要的影响。研究结合面的动态特性具有十分重要的意义,它是准确预测机械结构的特性,提高机械结构的性能的前提条件。结合面的研究工作可分为宏观研究和微观研究两方面,宏观研究一般是用弹簧和阻尼器模型来表示结合面,建立起振动系统的总体模型。微观研究主要是通过结合面变形的物理机理和结合面内阻尼特性的理论和实验研究来得到结合面的特性,要从本质上认识结合面的特性,一般多从微观领域进行研究。
本课题是云南省应用基础研究计划项目“机械结合面动态特性理论及应用研究”的一部分。本文结合目前国内外研究现状,对典型的平面结合面动态特性进行研究。利用有限元分析与实验模态分析相结合的方法对结合部等效参数进行识别。通过对不同表面粗糙度、不同结合面积和不同法向压力的相互作用的结合面动态特性的研究,分析了表面粗糙度、结合面积和法向压力对结合面特性参数的影响。通过分析可知：结合面刚度和阻尼随着结合面法向压力的增大而增大,随着结合面粗糙度的增大而减小；随着结合面面积的增大而增大。
本文抓住机械加工表面存在分形特征的特点,运用分形理论把两个相互接触的表面转化为无数对随机接触的微凸体。并结合经典的接触理论,从对一对微凸体的接触分析入手,进而建立无数对无规则排列的微凸体的理论接触模型。从微观方面入手,通过对实验数据和仿真数据对比分析,初步探索了结合面刚度和阻尼的产生原因和变化规律。并提出了微观接触变形理论。也在前人研究的基础上从能量损耗的角度对阻尼的产生原因进行了探索性分析。
实际的工作环境下,结合面对整个机构会有较大的影响。为了体现工程应用中结合面的影响,本文应用ANSYS分析软件,对存在结合面的机构和没有结合面的刚性体进行了对比分析。展示了二者固有频率和模态振型的差别。为把结合面的理论研究转换为实际应用奠定了基础。
Mechanical joints are natural structure in all Mechanical System. The dynamical characteristic of rigidity and damping will behave when loaded, which will affect greatly on the whole system. The elasticity and the damping in mechanical joints are often stronger than that in itself. So mechanical joints have an important effect on the dynamic characteristic of the whole machine tools. Therefore, there are great influences on studying the dynamic characteristic of the machine joints. It is a precondition to accurately predict characteristic and improve the functions of mechanical structures. The research of mechanical joints is divided into two parts, the macro part and the micro part. For the macro part, springs and dampers model are introduced to express mechanical joints and the vibration system model is built. For the other part, characteristic of the mechanical joints are analyzed through experiments which are based on theories of the mechanism in physics and damping attributions of the mechanical joints. Generally speaking, in order to recognize characteristic of mechanical joints, the research in micro fields usually comes first.
This thesis is a part of basic applied researching projects of Yunnan Province, which is named "The theory and applied research of dynamic characteristic of the mechanical joints". Based on the research status at home and abroad, this paper studies the dynamic characteristic of the typical plane mechanical joints. Equivalent parameters of the mechanical joints are identified through the combination of finite element analysis and experimental modal analysis. By studying the dynamic characteristic of interactive mechanical joints which have different surface roughness, contact area and vertical pressure, the effect of surface roughness, different contact areas and vertical pressure on equivalent parameters is analyzed. Through the analysis, we know that elasticity and damping of the mechanical joints are enhancing along with increasing of the vertical pressure and contact surface area, declining along with increasing of the surface roughness.
This thesis, aiming at the fractal feature which exists in mechanical surface and using the fractal theory, two mutually contacts surfaces are transformed into numerous random contractual micro convex bodies. Theoretical contact model of numerous irregular array micro convex bodies is established according to the classics contact theories from the analysis of a pair of micro convex body contact. From the micro aspect, the elasticity and the damping causes and changing rules are preliminary explored, and the micro contact deformation theory is put forward through the analysis of empirical datum and the simulated data. The damping production reasons are exploratory manner analyzed from the energy loss angle in the foundation of the predecessor studied.
In the actual working environment, the whole structure will be greatly influenced by mechanical joints. In order to show the effects of the mechanical joints in engineering applications, in this thesis, ANSYS software is used to analyze the distinction between the rigid body and joints, and the distinction between the natural frequencies and modal is showed. The foundation of converting theoretical study of mechanical joints to the practical application has been laid.
本课题是云南省应用基础研究计划项目“机械结合面动态特性理论及应用研究”的一部分。本文结合目前国内外研究现状,对典型的平面结合面动态特性进行研究。利用有限元分析与实验模态分析相结合的方法对结合部等效参数进行识别。通过对不同表面粗糙度、不同结合面积和不同法向压力的相互作用的结合面动态特性的研究,分析了表面粗糙度、结合面积和法向压力对结合面特性参数的影响。通过分析可知：结合面刚度和阻尼随着结合面法向压力的增大而增大,随着结合面粗糙度的增大而减小；随着结合面面积的增大而增大。
本文抓住机械加工表面存在分形特征的特点,运用分形理论把两个相互接触的表面转化为无数对随机接触的微凸体。并结合经典的接触理论,从对一对微凸体的接触分析入手,进而建立无数对无规则排列的微凸体的理论接触模型。从微观方面入手,通过对实验数据和仿真数据对比分析,初步探索了结合面刚度和阻尼的产生原因和变化规律。并提出了微观接触变形理论。也在前人研究的基础上从能量损耗的角度对阻尼的产生原因进行了探索性分析。
实际的工作环境下,结合面对整个机构会有较大的影响。为了体现工程应用中结合面的影响,本文应用ANSYS分析软件,对存在结合面的机构和没有结合面的刚性体进行了对比分析。展示了二者固有频率和模态振型的差别。为把结合面的理论研究转换为实际应用奠定了基础。
Mechanical joints are natural structure in all Mechanical System. The dynamical characteristic of rigidity and damping will behave when loaded, which will affect greatly on the whole system. The elasticity and the damping in mechanical joints are often stronger than that in itself. So mechanical joints have an important effect on the dynamic characteristic of the whole machine tools. Therefore, there are great influences on studying the dynamic characteristic of the machine joints. It is a precondition to accurately predict characteristic and improve the functions of mechanical structures. The research of mechanical joints is divided into two parts, the macro part and the micro part. For the macro part, springs and dampers model are introduced to express mechanical joints and the vibration system model is built. For the other part, characteristic of the mechanical joints are analyzed through experiments which are based on theories of the mechanism in physics and damping attributions of the mechanical joints. Generally speaking, in order to recognize characteristic of mechanical joints, the research in micro fields usually comes first.
This thesis is a part of basic applied researching projects of Yunnan Province, which is named "The theory and applied research of dynamic characteristic of the mechanical joints". Based on the research status at home and abroad, this paper studies the dynamic characteristic of the typical plane mechanical joints. Equivalent parameters of the mechanical joints are identified through the combination of finite element analysis and experimental modal analysis. By studying the dynamic characteristic of interactive mechanical joints which have different surface roughness, contact area and vertical pressure, the effect of surface roughness, different contact areas and vertical pressure on equivalent parameters is analyzed. Through the analysis, we know that elasticity and damping of the mechanical joints are enhancing along with increasing of the vertical pressure and contact surface area, declining along with increasing of the surface roughness.
This thesis, aiming at the fractal feature which exists in mechanical surface and using the fractal theory, two mutually contacts surfaces are transformed into numerous random contractual micro convex bodies. Theoretical contact model of numerous irregular array micro convex bodies is established according to the classics contact theories from the analysis of a pair of micro convex body contact. From the micro aspect, the elasticity and the damping causes and changing rules are preliminary explored, and the micro contact deformation theory is put forward through the analysis of empirical datum and the simulated data. The damping production reasons are exploratory manner analyzed from the energy loss angle in the foundation of the predecessor studied.
In the actual working environment, the whole structure will be greatly influenced by mechanical joints. In order to show the effects of the mechanical joints in engineering applications, in this thesis, ANSYS software is used to analyze the distinction between the rigid body and joints, and the distinction between the natural frequencies and modal is showed. The foundation of converting theoretical study of mechanical joints to the practical application has been laid.
引文
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[3]V. I. Ostrovskii. The Influence of Machining Methods on Slideway Contact Stifness, Machine and Tooling[J].1965,36(1):9-17
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[2]Z. M. Levina. Research on the Static Stiffness of Joints in Machine Tools[C].8th Interm. Con-r. M. T. D. R,1967
[3]V. I. Ostrovskii. The Influence of Machining Methods on Slideway Contact Stifness, Machine and Tooling[J].1965,36(1):9-17
[4]M. P. Dolbey, R. Bell. The Contact Stiffness of Joints at Low Apparent Interface Pressure[C]. Annals of CIRP,1970
[5]伊藤,周三.机床螺钉联接部位的静态特性[J].机床译丛,1980(2)：34～37
[6]F.希柯贝格,J.特鲁斯泰著.机床结构[M].北京：机械工业出版社,1982
[7]C. F. Beads. Damping in structural joints [J].The Shock and Vibration Digest, 1985:52(6):21～23
[8]R. Connoly, R. H. Thomley. Determining the Normal Stiffness of Joint Faces[J], ASME. Paper,1967.67:6～13
[9]R. H. Thomley, R. Connlly. M. M. Barash and F. Koenigsberger. The Effect of Surface Topography upon the Static Stiffness of Machine Tool Joints[J]. Interm. J. M. T. D. R.1965(5):57～74
[10]R. Connoly, R. E. Schofield and R. H. Thornley. The Approach of machined Surfaces with Particular Reference to Their Hard-Bess[J]. Proc.8th Interm. Confer. M. T. D. R.1967
[11]R. E. Schofield and R. H. Thomley. Mathematical Expression of Surface-finish Characteristics[J]. Confer. on Properties and Mechanical Engineers.1968
[12]R. E. Schofield. R. H. Thomley. Calculating the Elastic and Plastic Components of Deflection of Plane Joints Formed Machined Surfaces[C]. Proc.12th Confer. M. T. D. R.1971
[13]Huang Yumei etc. An Analytic Method of Joint Condition Damping Parameters in Dynamic Design of Mechanical System. Proc.3rd Inter. Conf. on High Tech. Chiba,1992:511～515
[14]黄玉美等.机床结构设计效果预断中结合条件的处理方法.机床,1990(6)：8 ～12
[15]堤正臣,伊东谊,益子正已.机床螺栓结合部的动态特性—固体接触状态.精密机械,1977(1)：105～111
[16]林耀民.机械结构结合面特征特征参数识别及系统动态特性研究：[硕士学位论文].北京：北京工业大学,1998
[17]伊东谊等.现代机床基础技术[M].北京.机械工业出版社,1987
[18]堤正臣.机床螺栓结合面的阻尼机理[J].机床译丛,1980,47(2)：26～29
[19]P. F. Rogers, G. Boothroyd. Damping at metallic interfaces subjected to oscillating tangential loads [J]. Eng. for Industry, Tran (ASME),1975,78(4):1087～1093
[20]C. Dekonick. Deformation properties of metallic contact surfaces of joints under the influence of dynamic tangential loads [J]. Mach. Des. Res,1975(3): 193～199
[21]P. B. ъликв.机床螺纹联接的阻尼[J].机床译丛,1980,47(2)：6～9
[22]戴德沛.阻尼减振降噪技术[M].西安：西安交通大学出版社,1986
[23]伊藤.周三.机床螺钉连接部位的静态特性[J].机床译丛,1980,47(4)：34～37
[24]刘晓萍.基于正交条件识别机械结构结合面参数方法的改进.应用力学学报,1996(3)：103～109
[25]刘晓萍.机械结构结合面阻尼系数识别的研究.振动与冲击,1995(3)；61～65
[26]张学良,温淑花.机械结构局部物理参数的一种识别方法.太原重型机械学院学报,1993,14(4)：85～88
[27]张学良,黄玉美等.机械结合面阻尼参数识别的一种方法.西安理工大学学报,1999,15(1)：98～100
[28]张学良,黄玉美机械结合面动态参数识别的优化方法.太原重型机械学院学报,1995,16(4)：85～88
[29]宋健伟.机械结构动力修改方法及实验模态分析技术的研究[D].天津：天津大学,1989
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