返回
类型 基础研究 预答辩日期 2017-11-21
开始(开题)日期 2014-12-11 论文结束日期 2017-09-04
地点 机械楼第一会议室 论文选题来源 973、863项目     论文字数 6.6 (万字)
题目 螺栓连接力学特性建模及在数控刀架系统中的应用
主题词 螺栓固定结合面,有限元建模,非线性模型验证,动力学分析,数控刀架
摘要 现代数控装备正在向高速、高精度、高可靠性方向发展,而机床功能部件性能保持能力在很大程度上阻碍了我国机床行业的发展。数控刀架作为最重要的功能部件之一,其动、静态特性在很大程度上直接影响和决定机床整机的精度和刚度匹配。相关研究表明螺栓结合面对机床整机以及数控刀架力学特性影响显著。螺栓连接成本低、制造简单,并广泛应用于现代装备结构中,螺栓连接的动态特性直接影响整机的性能。螺栓连接力学特性的建模方法一直是机床及数控刀架整机建模研究的重点和难点。 为了建立较为准确的整机模型,必须对螺栓固定结合面的建模方法以及非线性力学行为进行研究。本文在国家科技重大专项(No.2012ZX04002032,No.2013ZX04012032)的资助下开展螺栓固定结合面建模方法和非线性特性分析的研究和探索工作。从螺栓固定结合面的有限元建模方法研究出发,对螺栓固定结合面的动态特性和非线性振动开展研究工作。围绕预紧力、外载荷和螺栓设计参数对螺栓连接动力学特性影响、螺栓固定结合面非线性参数识别方法、螺栓固定结合面非线性动力学实验以及螺栓固定结合面有限元建模应用于数控刀架端齿盘结构优化等关键问题逐步展开研究。论文的主要内容包括以下几个方面: 1、研究了7种不同的螺栓有限元建模方法,包括预紧力模型、热应力模型、梁单元模型、MPC约束法、刚性连接模型、等效接触面积方法、虚拟材料模型等,并通过模态实验验证建模方法的准确性。以模态试验结果为依据,对比和讨论了不同螺栓连接有限元模型的优缺点,为后续数控刀架整机建模和端齿盘结构优化分析提供研究手段和依据。 2、通过扫频和脉冲激励实验方法研究螺栓结合面动力学行为,研究预紧力和外载荷力等因素对螺栓固定结合面振动传递特性的影响。分析结果表明,螺栓连接结构的动力学特性直接受到预紧力和外载荷的影响,并表现出不同程度的非线性,这为后续螺栓固定结合面非线性动力学实验和参数识别方法的研究提供了重要的依据和支撑。同时,讨论公称直径、螺栓数目等设计参数对螺栓连接力学特性的影响,将焊接的连接方式和螺栓连接方式进行相比。 3、提出等效线性函数法的非线性动力学参数识别方法。等效线性函数法基于谐波平衡法理论,识别精度高,表现出较好的工程应用前景。非线性弹簧和阻尼力通过谐波平衡法的一阶近似展开可推到出等效线性函数,等效线性刚度和阻尼随着响应幅值的变化而改变,可完成非线性动力学模型确认和参数识别。数值分析结果证明等效线性函数法可完成典型数值案例非线性参数识别,包括立方刚度、五次方刚度、库伦摩擦阻尼、分段线性刚度、双线性刚度、复合非线性等7种非线性模型。数值案例成功证明等效线性函数法可用于不同类型非线性的参数识别,并取得理想的识别精度,可有望用于实际非线性结构的检测和建模,解决螺栓固定结合面动力学模型确认问题。 4、搭建螺栓固定结合面非线性振动实验平台,并完成螺栓固定结合面非线性动态特性实验。等效线性函数法应用于螺栓固定结合面非线性参数识别研究。识别结果具有一定的精度,在一定程度上反映螺栓固定结合面软刚度和硬阻尼的非线性特性,并证明螺栓连接结合面高阶多项式非线性弹簧和阻尼力的存在。提出恒响应扫频实验方法,恒响应扫频实验需不断调整基础激励输入的大小以严格控制响应点输出,适合一些精密设备和仪器的非线性测试。这也为等效线性函数法用于其他工业装备非线性参数的识别研究提供了重要的实验和理论依据。 5、根据数控刀架的结构特点、工作原理、端齿盘设计原则及工作状态下的受力状态,应用螺栓结合面建模方法,建立数控刀架有限元模型,辨识刀架刚度薄弱环节,优化端齿盘齿形结构,包括齿形角、齿数、内外齿长比、齿根宽。依据国标规范和相关测试标准,提出数控刀架静刚度测试方案,搭建静刚度测试平台,完成数控刀架静刚度测试,验证了数控刀架有限元模型的合理性,同时试验结果也为端齿盘结构优化和刀架可靠性分析提供数据。 论文从数控刀架整机建模出发,开展螺栓连接力学特性关键技术研究。在螺栓固定结合面有限元建模方法、螺栓连接动态特性影响因素,螺栓结合面非线性动力学实验及参数识别方法等方面取得了阶段性成果。
英文题目 MODELING OF MECHANICAL PROPERTIES OF BOLTED JOINT INTERFACE AND ITS APPLICATION IN CNC TURRET SYSTEM
英文主题词 bolted joint interface, finite element modelling, nonlinear model validation, dynamic analysis, CNC turret
英文摘要 Modern CNC (Computer Numerical Control) equipment has the property of high-speed, high precision and high reliability, while its supplementary machine tool component’s performance has hindered the development of China’s machine tool industry for long. As one of the most important functional components of machine tool, the CNC turret directly influences the machine tool’s precision and stiffness matching. It is shown that bolted joint interface has a significant effect on the dynamics of machine tool or CNC turret system. Due to its low cost and easy fabrication, bolted joint has been widely used in modern structural equipment, and its dynamics directly influences the whole machine’s performance. The modelling of bolted joint interface is one of the most subject problems that need to be solved for machine tool or servo turret’s modeling. In order to establish a more accurate model of machine tool, modeling of bolted joint interface must be considered for investigation of machine tool’s dynamic characteristic. The modeling of bolted joint interface and its nonlinear property are investiaged under the fund of “National Science and Technology major projects” (No.2012ZX04002032,No.2013ZX04012032). The project begans with the finite element modeling of bolted joint interface, the vibration peoperty and nonlinear behavior of bolted joint is studied then. Some subjects are carried out in this paper , such as the effect of preload, exterior loading and corresponding design method of bolted joint’s dynamics, nonlinear parameter identification method, modeling of bolt joint interface and optimization of CNC turret. The main contents are as follows: 1、Seven kinds of finite element modeling methods for bolted joint interface are studied, such as preload model, thermal stress model, beam element model, MPC constraint, equivalent contact area method and virtual material method, which can be validated by modal test process. The modelling accuracy of different modelling technique is compared with each other according to modal test results, which supplies the finite element technique for subsequent turret’s modeling and indexing tool optimization. 2、The effect of bolted joint interface on structural dynamic response is investigated by hammer and sine sweep test procedure, and the effect of both preload and external loading on vibration transmission is also studied. It shows that the vibration property of bolted joint interface is directly affected by preload and external loading levels, and the nonlinear behavior of bolted joint interface can be observed during test procedure, which provides the foundation of subsequent nonlinear parameter identification and vibration test for bolted joint interface. Meanwhile, the effects of some design parameters, such as nominal diameter, number of bolted joints on the vibration response are discussed, and the welded joints’ dynamics are compared with bolted joints. 3、The equivalent linear function method based on the first-order approximation of harmonic balance method is proposed for nonlinear parameter identification, which shows a satisficed identification precision and promising engineering value. The nonlinear stiffness and damping will be regarded as the function of response amplitude, proposes a representation of the internal non-linear force and provide its harmonic response prediction, which can be used for the nonlinear parameter identification and non-linear inspection. Some numerical simulation of typical nonlinear numerical models, such as cubic stiffness, five order stiffness, coulomb damping, pieacwise stiffness, bilinear stiffness and combined nonlinearity are carried out by simulation process for validity of this method. The equivalent linear function method can be used for parameter identification for various nonlinearities according to numerical results, and the identification resuts is so satisfied that it can be used for inspecting and modelling of nonlinear structures and solution of problems within characterization of nonlinearity of bolted jont interface. 4、An experimental platform is founded for dynamic investigation for bolted joint interface. The equivalent linear function method is utilized for nonlinear parameter identification of bolted joint interface in dynamic property test. And the identification result is so satisfied that it can reveal the softening nonlinear stiffness and hardening nonlinear damping and validate the existence of nonlinear spring and damping force in polynomials form along bolted joint interface. The control system continually adjusts the level of basic input excitation to conduct the response control harmonic test, which is suitable for nonlinear test for precision equipment. The equivalent linear function method is proved experimentally that it can be used for nonlinear parameter identification for other industrical instrument. 5、Servo turret’s structural characteristics, working principle and loading condition is analyzed, and the finite element model of CNC turret is simplified to optimize the structural parameters of the end-tooth plate such as tooth profile angle, tooth number, teeth length ratio and tooth width by considering the modeling of bolted joint. According to the national standard static stiffness test platform of CNC turret is set up to complete the CNC turret performance test, which will identify the low stiffness part of the CNC turret, improve its operation performance and validate finite element model. Experimental results will provide reliability data and optimization analysis for the CNC turret structure and indexing plate. The investigation of mechanical property of bolted joint is carried out in this study, which begans with the modelling of CNC turret. Some meaningful research results of bolted joint interface have been obtained during this invstigation, such as finite element modeling method, influencing factors, nonlinear dynamic test and the nonlinear parameter identification procedure .
学术讨论
主办单位时间地点报告人报告主题
结构动态优化实验室 2016-8-2 机械楼327 刘鑫 机床滑动导轨结合面理论
结构动态优化实验室 2017-5-13 机械楼327 刘鑫 机床固定结合面基础理论研究
结构动态优化实验室 2015-5-8 机械楼327 刘鑫 数控刀架静刚度测试原理
机械工程学院 2017-5-13 纪忠楼y214 周徐斌 航天工程与卫星结构机构技术
机械工程学院 2016-5-18 机械楼南高厅 Gabor Stepan Delayed oscillators and wheel shimmy
结构动态优化实验室 2015-10-13 机械楼327 刘鑫 数控刀架静刚度分析
结构动态优化实验室 2017-6-5 机械楼327 李烈 减振刀具橡胶材料的摩擦阻尼和粘性阻尼
机械工程学院 2017-4-27 机械楼327 石灵健 不同砂光机的振动试验测试结果
     
学术会议
会议名称时间地点本人报告本人报告题目
东南大学机械学院 2016-12 机械楼南高厅 工作模态理论及工程测试方法
美国声学学会 2015-8 旧金山 Extraction and linearization of nonlinear systems based on frequency response functions
     
代表作
论文名称
Identification of Nonlinear Parameter of Mechanical Joint System Based on Vibration Tests
Experimental Investigation of Dynamics of Assembly with Typical Mechanical Joint
Extraction and linearization of nonlinear systems based on frequency response functions
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
陈南 正高 教授 博导 东南大学
李舜酩 正高 教授 博导 南京航空航天大学
张建润 正高 教授 博导 东南大学
李普 正高 教授 博导 东南大学
陆宝春 正高 教授 博导 南京理工大学
      
答辩秘书信息
姓名职称工作单位备注
陈斌 其他 学院研究生办秘书 东南大学