Mughal Khurram Hameed, Shirinzadeh Bijan, Qureshi Muhammad Asif Mahmood, Munir Muhammad Mubashir, Rehman Muhammad Shoaib Ur
Robotics and Mechatronics Research Laboratory (RMRL), Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, VIC 3800, Australia.
Mechanical Engineering Department, University of Engineering and Technology, Lahore 54890, Pakistan.
Sensors (Basel). 2024 Sep 18;24(18):6027. doi: 10.3390/s24186027.
The use of advanced brittle composites in engineering systems has necessitated robotic rotary ultrasonic machining to attain high precision with minimal machining defects such as delamination, burrs, and cracks. Longitudinal-torsional coupled (LTC) vibrations are created by introducing helical slots to a horn's profile to enhance the quality of ultrasonic machining. In this investigative research, modified ultrasonic horns were designed for a giant magnetostrictive transducer by generating helical slots in catenoidal and cubic polynomial profiles to attain a high amplitude ratio (TA/LA) and low stress concentrations. Novel ultrasonic horns with a giant magnetostrictive transducer were modelled to compute impedances and harmonic excitation responses. A structural dynamic analysis was conducted to investigate the effect of the location, width, depth and angle of helical slots on the Eigenfrequencies, torsional vibration amplitude, longitudinal vibration amplitude, stresses and amplitude ratio in novel LTC ultrasonic horns for different materials using the finite element method (FEM) based on the block Lanczos and full-solution methods. The newly designed horns achieved a higher amplitude ratio and lower stresses in comparison to the Bezier and industrial stepped LTC horns with the same length, end diameters and operating conditions. The novel cubic polynomial LTC ultrasonic horn was found superior to its catenoidal counterpart as a result of an 8.45% higher amplitude ratio. However, the catenoidal LTC ultrasonic horn exhibited 1.87% lower stress levels. The position of the helical slots was found to have the most significant influence on the vibration characteristics of LTC ultrasonic horns followed by the width, depth and angle. This high amplitude ratio will contribute to the improved vibration characteristics that will help realize good surface morphology when machining advanced materials.
在工程系统中使用先进的脆性复合材料使得有必要采用机器人旋转超声加工，以实现高精度并将诸如分层、毛刺和裂纹等加工缺陷降至最低。通过在变幅杆轮廓上引入螺旋槽来产生纵向 - 扭转耦合（LTC）振动，以提高超声加工质量。在这项研究中，通过在悬链线和三次多项式轮廓中生成螺旋槽，为超磁致伸缩换能器设计了改进的超声变幅杆，以获得高振幅比（TA/LA）和低应力集中。对带有超磁致伸缩换能器的新型超声变幅杆进行建模，以计算阻抗和谐波激励响应。基于块 Lanczos 和全解方法，使用有限元方法（FEM）进行结构动力学分析，研究螺旋槽的位置、宽度、深度和角度对不同材料的新型 LTC 超声变幅杆的固有频率、扭转振动幅度、纵向振动幅度、应力和振幅比的影响。与具有相同长度、端部直径和工作条件的贝塞尔和工业阶梯式 LTC 变幅杆相比，新设计的变幅杆实现了更高的振幅比和更低的应力。发现新型三次多项式 LTC 超声变幅杆由于振幅比高 8.45%而优于其悬链线对应物。然而，悬链线 LTC 超声变幅杆的应力水平低 1.87%。发现螺旋槽的位置对 LTC 超声变幅杆的振动特性影响最大，其次是宽度、深度和角度。这种高振幅比将有助于改善振动特性，有助于在加工先进材料时实现良好的表面形貌。
