纵-扭复合超声振动加工系统设计及频率简并研究

纵-扭复合超声振动加工技术在硬脆性材料的加工中受到越来越多的重视，针对该种需求，设计了一种纵-扭复合超声振动加工系统，基于有限元方法对该类系统普遍存在的频率简并问题进行了研究。利用数值解析方法设计出超声换能器和超声变幅杆，之后在变幅杆上做出螺旋槽，一部分纵向振动转换为扭转振动；以目标频率附近的纵、扭谐振频率尽量接近为原则，利用有限元软件分析系统的结构参数对纵、扭谐振频率的影响规律，实现频率简并；在此基础上对系统进行模态分析和瞬态动力学分析，结果表明系统可以实现纵-扭复合超声振动，验证了此种频率简并方法的有效性和实用性。

Design of Longitudinal -Torsional Ultrasonic Vibration Machining System and Research on Resonant Frequency Degeneration

Longitudinal-torsional ultrasonic vibration machining has attracted more and more attention on hard and brittle materials machining, for this kind of need, a longitudinal-torsional ultrasonic vibration system was designed, researches were made on the frequency degeneration issue which is ubiquitous in this kind of system based on finite element analysis. An ultrasonic transducer and a composite horn were designed using analytical method, after that, helical slots were made on the horn, which made part of the longitudinal vibration convert to torsional vibration; Based on the principle of “the closer the longitudinal-torsional resonant frequencies, the better”, the relationship between longitudinal, torsional resonance frequency and structural parameters was researched using finite element analysis software, which led the achievement of frequency degeneration; After that, modal analysis and transient analysis showed the system could achieve longitudinal-torsional ultrasonic vibration, which verified the effectiveness and practicality of this kind of frequency degeneration method.