Numerical Investigation of the Effect of Uniform Cutout on Performance of Ultrasonic Horn for Machining Nomex Honeycomb Core Material

Abstract

Ultrasonic horn is utilized in order to enhance the amplitude of vibration transmitted by the transducer in an ultrasonic machining system. It plays a vital role in vibration amplification to a magnitude suitable for efficient machining of materials. Ultrasonic machining system has to operate at a frequency of at least . Therefore, horn may be subjected to high magnitude of stresses leading to failure. Mechanical horn is designed to get optimum vibration amplification while keeping stresses in acceptable limits. In this research an ultrasonic compound horn was designed with through cutout of uniform diameter. The performance of ultrasonic horn was observed by varying the cutout diameter by modelling horns of four different materials: titanium, aluminum, steel and stainless steel respectively. Modal analysis was performed for computing modal frequencies in the axial direction, whereas harmonic analysis was carried out in order to determine vibration amplitude, stresses and factor of safety. The effect of varying frequency ratio on vibration magnification, stresses, and factor of safety were also investigated. The axial modal frequency was observed to increase, whereas amplitude of vibration and stresses were observed to decrease by increasing the cutout size. Titanium was found to be the most suitable material for ultrasonic horns, because it provided up to 159.4 % more amplitude of vibration and 3 times higher safety factor thus operating life as compared to other materials.