附件化超声振动工作台设计及有限元优化分析

超声振动辅助加工为合金材料、硬脆材料和复合材料等难加工材料提供了有效的机械制造解决方案，超声振动辅助加工装置结构复杂、专业化程度高、使用可靠性差等因素制约了超声加工技术的推广及民用化历程。为了推广超声振动辅助加工的应用范围，基于超声能量传播原理，设计了一种机床附件化的超声振动工作台，能够方便地安装于加工中心上为工件提供超声振动辅助加工。首先，选用2种材料对工作台进行整体结构设计，通过模态分析确定工作台的工作频率及振动形式，使用谐响应分析揭示工作台工作时的稳定情况。其次，采用多目标优化方法对工作台进行结构优化，在保证总模态变形量不变的情况下降低振动台的质量，以减小超声能量损耗的同时提高振动状态的可靠性。最后，对比优化前后的有限元分析结果确定工作台材料并进行尺寸调整，使其更加符合实际加工需要。分析结果表明，45#钢工作台在工作时的振动稳定性要好于Cr12Mov钢工作台，但Cr12Mov钢工作台具有较大振幅。通过多目标优化使得振动台的总体质量降低27%，其工作频率同时降低11%，优化后2种工作台的共振频率带宽相差较小。 

Design and finite element optimization analyses of accessory ultrasonic vibration working table

Ultrasonic vibration assisted machining provides effective manufacturing solutions for difficult-to-machine materials such as alloy materials, brittle materials and composite materials, which is widely used in aerospace, defense, electronics and other high-technology fields. The complex structure, high degree of specialization and poor reliability of ultrasonic vibration assisted machining device restrict the promotion of ultrasonic processing technology. In order to popularize the application scope of ultrasonic vibration assisted machining, an accessory ultrasonic vibration working table is designed based on the principle of ultrasonic energy transmission, which can be conveniently installed in the machining center to provide ultrasonic vibration assisted machining for the workpiece. First, two types of materials were applied to structural design of the table, the working frequency and vibration form were determined through the modal analysis, and the working stability was presented by harmonic response analysis. Second, the working table structure optimization was carried out by the method of multi-objective optimization. The quality of the working table was reduced under the condition of guaranteeing invariable total deformation, in order to reduce the loss of ultrasonic energy and improve the working reliability. Finally, in order to make the working table more suitable for the actual machining needs, the material of the working table was selected and the table size was adjusted by comparing the results of finite element analysis before and after optimization. The results of analysis indicate that 45 # steel vibration working table has better vibration stability and smaller vibration amplitude. The overall mass of the vibration table was reduced by 27%, the working frequency was reduced by 11% through multi-objective optimization. The bandwidth difference of resonance frequency between the two workbenches is quite small.