大功率纵扭复合超磁致伸缩旋转超声加工系统设计理论与加工机理

项目名称： 大功率纵扭复合超磁致伸缩旋转超声加工系统设计理论与加工机理

项目编号： No.51475260

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 机械、仪表工业

项目作者： 冯平法

作者单位： 清华大学

项目金额： 84万元

中文摘要： 旋转超声加工已被大量的理论和试验证实是硬脆材料高效精密加工的一种有效方法。前期研究表明，提高超声加工实际输出功率和附加扭转振动均对旋转超声加工性能有积极影响。超磁致伸缩换能器可以产生远高于传统压电陶瓷换能器的机械振动动率。本课题将超磁致伸缩换能设计首次引入旋转超声加工系统，研究超磁致伸缩纵扭复合振动发生模式、超声波发生器-换能器-变幅杆-磨粒工具整体结构精确协调设计方法及性能评价方法，及其相关参数对超声功率和换能效率的影响机制，开发一种超磁致伸缩大功率纵扭复合旋转超声加工系统。选取航空航天典型SiC基/增强相复合材料研究超磁致伸缩纵扭复合超声加工过程中刀具-工件界面相互作用行为、工具磨损和材料去除机理，获取加工外场量（磁路参数、纵扭复合形式、超声功率、切削参数等）对加工效率、加工表面完整性、亚表面损伤等加工特征的影响规律，为硬脆材料大功率纵扭复合超声振动高效低损伤精密加工技术提供理论指导。

中文关键词： 旋转超声加工；大功率；超磁致伸缩；纵扭复合振动；加工机理

英文摘要： Rotary ultrasonic machining (RUM), explored in many experimental and theoretical investigations, has been regarded as an effective processing method for hard-brittle materials. Previous studies showed that the increase of ultrasonic power or additional torsional vibration in rotary ultrasonic machining could have a positive impact on the machining performance. In this study, we introduce the giant magnetostrictive transducer into the traditional rotary ultrasonic machining system, and discuss the generation mode of giant magnetostrictive longitudinal torsional vibration. An accurate coordination design method and a performence evaluation method is presented to get the best structure of ultrasonic generator, transducer, horn and abrasive tool. Influence mechanisms of the design parameters on the obtained maximum ultrasonic power and the transducer efficiency are investigated. Then, a giant magnetostrictive high-power rotary ultrasonic longitudinal torsional machining system is developed. SiC matrix composites are selected to explore the interaction behavior of tool-workpiece interface, tool wear and its material removal mechanism in the developed giant magnetostrictive high-power rotary ultrasonic longitudinal torsional machining system. Effects of structural design parameters and process variable (magnetic circuit parameters, longitudinal torsional mode, ultrasonic power, cutting parameters, etc.) on the machining performance, such as cracks generation and expansion, material removal efficiency, machined surface integrity, sub-surface damage, are discussed. A theoretical guidance is proposed for high efficiency and low damage precision processing technology of hard and brittle materials using the developed high-power rotary ultrasonic longitudinal-torsional machining system, which is the research objective of this project.

英文关键词： Rotary ultrasonic machining;High-power;Giant magnetostrictive;Longitudinal-torsional composite vibration;Machining mechanism