纵－扭复合超声振动加工系统设计及频率简并研究

摘要

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。%Longitudinal-torsional composite ultrasonic vibration machining technique attracts more and more attentions in hard and brittle materials machining,for this kind of requirement,a longitudinal-torsional composite ultrasonic vibration machining system was designed,the frequencies merging problem existing in this kind of system was studied based on the finite element analysis.An ultrasonic transducer and a composite horn were designed using the numerical analysis method.After-ward,helical slots were made on the horn,parts of its longitudinal vibrations were converted into its torsional vibrations.Based on the principle that “the closer the longitudinal natural frequencies and the torsional natural ones,the better the results”,the offects of the system's parameters on its longitudinal natural frequencies and torsional natural ones were analyzed with a finite element analysis software to realize its natural frequencies merging. At last,the system's modal analysis and transient dynamic analysis showed that the system can realize longitudinal-torsional composite ultrasonic vibration,the effectiveness and applicability of this kind of frequencies merging method are verified.