Theoretical Investigations of the Ultrasonic Wave Generation by an Electromagnetic Acoustic Transducer

Abstract

Background. The article considers the analysis of the electromagnetic acoustic (EMA) converter with controlled angular input of acoustic waves, using parameters influencing the formation of an acoustic wave. Objective. The aim of the paper is to analyze the formation of an acoustic wave with angular input in the EMA converters of non-destructive testing systems. Methods. Mathematical modelling was used to investigate the influence of the distance from the yarn-emitters to the control object surface. The influence of various factors (current magnitudes, external magnetic field values, distance from the yarn-emitter and the grating to the control object surface) is investigated with the help of mathematical modeling. Results. The optimal value of the magnetic induction of an external magnetic field is shown. The calculation of the pressure created by the yarn-emitters and the grating on the controlled object surface was carried out. A formula for the ultrasonic wave input angle was obtained. The formula depends on the parameters of the control environment, the distance between the emitters, the phase shift between the harmonic current signals applied to the adjacent emitters and the harmonic signal frequency. It was found that a change in the angle between the EMA transducer and the surface of the control object leads to a significant deterioration in the acoustic wave generation on the surface of the controlled object. Conclusions. We investigated the possibility of the angular input of an ultrasonic wave using system of parallel-arranged yarn-emitters. A decrease in the acoustic pressure, with increasing distance from the yarn-emitters to the controlled object surface was observed.

Keywords

• EMA transducer
• Acoustic pressure
• Non-destructive testing
• Angular input
• Ultrasonic wave