Influence of the Fillet Radius on the Performance of an Ultrasonic Stepped Velocity Transformer

Authors

DOI:

https://doi.org/10.20535/2521-1943.2025.9.4(107).343198

Keywords:

ultrasound, velocity transformer, fillet radius, resonance frequency, amplification coefficient, finite element method.

Abstract

This study presents the results of a numerical investigation into the influence of geometric parameters, particularly the fillet radius, on the dynamic characteristics of an ultrasonic stepped velocity transformer. Such transformers are employed in high-frequency electromechanical systems to match the acoustic impedances between the transducer and the load, as well as to increase the amplitude of mechanical vibrations. Modeling was carried out using the finite element method (FEM), which enables consideration of the spatial distribution of stresses and strains within the transformer volume. The effects of the step diameter and acoustic length on the resonance frequency and amplification coefficient were analyzed. It has been established that an increase in the step diameter leads to a decrease in the resonance frequency, whereas an increase in the fillet radius results in its rise. Quantitative relationships between the fillet radius, transformation coefficient, and resonance frequency were obtained, allowing for approximate determination of optimal design parameters. It was shown that enlarging the fillet radius reduces stress concentration in the transition zone between steps, thereby enhancing the fatigue strength of the structure. An empirical relationship was proposed for preliminary estimation of the fillet radius to ensure agreement between the actual and the calculated resonance frequencies. The results obtained can be applied in the design and optimization of ultrasonic amplification systems and transducers used in ultrasonic welding, material processing, and surface modification technologies.

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Published

2025-12-29

How to Cite

[1]
A. Movchanuk, O. Luhovskyi, A. Shulha, and A. Novosad, “Influence of the Fillet Radius on the Performance of an Ultrasonic Stepped Velocity Transformer”, Mech. Adv. Technol., vol. 9, no. 4(107), pp. 425–431, Dec. 2025.

Issue

Vol. 9 No. 4(107) (2025)

Section

Mechanics

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Copyright (c) 2025 Андрій Мовчанюк, Олександр Луговський, Аліна Шульга, Андрій Нововсад

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