Abstract:

In order to meet the functional requirements of the ultrasonic vibration assist integrated heating/molding processes（UVAIMPs） of thermoplastic FMLs for a variable-dimensional ultrasonic machining system， a novel design method by cooperating the frequency offset compensation with stepwise hierarchical optimization was put forward. After the stepped wide blade ultrasonic sonotrode designed by using the above method was assembled with the specified ultrasonic generator and transducer， the corresponding vibration characteristics were measured with a laser vibrometer. The results show that the above sonotrode may operate stably at a resonance frequency of 20 101 Hz. Under the 50% output power of ultrasonic generator， the maximum vibration displacement reaches 16 μm on end faces and 12.7 μm on lateral faces under the condition that the amplitude uniformity is larger than 90%， and the corresponding effective working regions are 110 mm×30 mm and 110 mm×16 mm. Thus， the sonotrodes with both of end and side working faces are realized to satisfy the demands of the variable-dimensional ultrasonic machining system for UVAIMPs of thermoplastic FMLs. The present work verifies the feasibility and effectiveness of the proposed design method.

Key words: thermoplastic fiber metal laminate（FML）, ultrasonic vibration, wide blade sonotrode, structural parameter optimization, frequency offset compensation

摘要：

为满足热塑性纤维金属层合板材料超声振动辅助加热/成形一体化工艺（UVAIMP）中变维超声加工系统的功能要求，提出频率偏移补偿协同分步逐级优化的端/侧两面加工宽刃超声工具头设计方法。所设计加工的超声工具头在与超声发生器、换能器组成超声加工系统后，采用激光测振仪对其进行振动特性测量，结果表明：超声工具头可在20 101 Hz谐振频率下稳定工作，在50%的超声发生器功率输出情况下，其输出端面和侧面振动位移均匀区域的最大振幅分别达到16 μm和12.7 μm，有效工作区域分别达到110 mm×30 mm和110 mm×16 mm，振幅均匀度高于90%，满足前述变维超声加工系统对超声工具头端/侧两面加工的振动特性要求，证实了所提出的设计方法的可行性和有效性。

关键词: 热塑性纤维金属层合板, 超声振动, 宽刃工具头, 结构参数优化, 频率偏移补偿