【作者】 张冠英；

【导师】 康仁科；

【作者基本信息】 大连理工大学 ， 机械工程， 2012， 硕士

【摘要】 超声波加工已广泛应用于各种工程领域,并且在半导体和不导电非金属硬脆材料的精密加工中,体现出了普通加工无法比拟的工艺优越性。超声振动磨削加工是超声加工方法中的一种,其与传统磨削加工相比在提高材料去除率、提高工件表面加工质量等方面具有十分显著的优势。杯形磨削工具在硬脆材料加工中具有十分广泛的应用,例如可用于平面的超声辅助磨削加工、大直径孔和圆柱棒料的套料加工等,但其尺寸通常较大且形状较为复杂,对超声系统的振动状态影响较大。因此,为了获得准确的超声系统谐振频率、稳定均匀的超声振幅输出,将杯形磨削工具与变幅杆进行一体化设计。本文基于超声波纵弯模态转换,对杯形工具变幅杆振动系统进行了理论设计、有限元仿真、振动状态验证试验以及设计仿真软件的开发,主要工作及研究内容如下：1.结合杯形工具变幅杆振动系统的结构特点,对超声波在中间段薄圆盘中的振动模态进行分析,推导出描述薄板弯曲振动模态的位移方程,并进一步分析得出超声波在系统中的模态转换形式,以此为基础并结合系统三段的位移函数以及相应的边界条件,通过变幅杆的传统设计法推导出杯形工具变幅杆振动系统的频率方程,并带入预设的已知材料属性参数与尺寸参数对系统进行了理论设计。2.利用大型通用有限元分析软件ANSYS对理论设计的杯形工具变幅杆振动系统进行有限元仿真分析,建模参数为预设的材料属性参数及利用所推导频率方程计算出的系统尺寸参数,有限元分析类型选择模态分析,仿真出的振动系统振动状态良好,振幅放大作用明显,仿真频率(22370Hz)与理论设计频率(25000Hz)较为接近,验证了系统的模态转换理论。3.搭建杯形工具变幅杆振动系统振动状态验证试验平台,试验平台由超声波发生器、压电陶瓷超声换能器、杯形工具变幅杆振动系统、激光位移传感器以及示波器组成。试验测量结果显示,系统输出端面振幅为6μm,系统谐振频率为20223Hz,略低于有限元仿真频率22370Hz,系统振动状态良好,输出端面振幅均匀,与理论设计与有限元仿真分析结果符合的很好。4.基于MATLAB与ANSYS的联合调用,开发了一款变幅杆设计软件,软件主要用于对杯形工具变幅杆振动系统及常用的各种类型变幅杆进行理论设计与有限元仿真分析,软件界面友好,操作简便,功能强大。更多还原

【Abstract】 Ultrasonic processing has been widely used in all kinds of engineering fields, which shows great superiority over the traditional processing, especially in the precision processing of semiconductors and non-conducting nonmetallic hard brittle materials. Ultrasonic vibration aided grinding is one of ultrasonic processing methods, which has greater advantage in increasing material removal rate and making the quality of processing surface higher compared with the traditional grinding.Cup grinding tools are widely used in the processing of hard brittle materials, such as the ultrasonic vibration aided grinding of parts’surface, the nesting processing of the large diameter hole and the cylindrical bar. But the size of the cup grinding tools are always big, which has big effect on the vibrating condition of the ultrasonic vibration system. So for getting an accurate resonant frequency, stable and average output, integrated design of the horn and the cup grinding tool is proposed.This article is based on the longitudinal-bending mode transition of the ultrasonic in the vibration system, which performs a theoretical design, finite element simulation and develops a design software for the cup tool horn vibration system. The main work and results are as follows:1. According to the structural characteristics of the cup tool horn vibration system, analysis has been performed on the ultrasonic vibration mode in the thin disk of the vibration system, the bending mode displacement equation of the thin disk is given, eventually the mode transition form of the ultrasonic in the vibration system is. figured out. Based on the mode transition form and combined with the displacement equation of the vibration system’s three parts and their relevant boundary conditions, using the traditional horn design method the frequency equation of the vibration system is derived. With the default material attribute parameters and size parameters bringing into the derived frequency equation, the theoretical design of the vibration system is finally accomplished.2. Finite element simulation is performed using ANSYS on the vibration system that has been theoretically designed, the modeling parameters are from the default material attribute parameters and the derived size parameters, simulation type is chosen as the mode analysis. The analysis results reveal that the vibration system performs quite good vibrating condition and the magnification factor is quite big. The simulation resonant frequency(22370Hz) is quite close to the theoretically designed resonant frequency(25000Hz), proving the mode transition theory of the vibration system. 3. The vibrating condition testing experimental platform for the designed vibration system is set up, the platform is made up of ultrasonic generator, piezoelectric ceramic transducer, cup tool horn vibration system, laser displacement sensor and oscilloscope. The measuring results show that the amplitude of the output surface is6μm, the resonant frequency the vibration system is20223Hz which is a little lower than the simulation resonant frequency, the vibrating condition of the vibration system is excellent, the amplitude of the output surface is quite even. The experimental results correspond perfectly with the results of finite element simulation and theoretical design.4. Based on the combined use of the MATLAB and ANSYS, a horn design software has been developed. This software is used for the theoretical design and finite element simulation of the cup tool horn vibration system and other common types of horns, it provides friendly interface, convenient operation and strong function.更多还原