Finite Element Modeling of a Pulsed Spiral Coil Electromagnetic Acoustic Transducer (EMAT) for the Testing of Plates

R. Dhayalan[1], A. Kumar[2], B. Purnachandra Rao[3], T. Jayakumar[2]
[1]Metallurgy and Material Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, 603 102, TN, India
[2]Nondestructive Evaluation Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, 603 102, TN, India
[3]Ultrasonic Measurements Section, Nondestructive Evaluation Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, 603 102, TN, India
Published in 2013

This paper presents numerical simulation of plate wave modes in thin stainless steel plates using a racetrack spiral coil electromagnetic acoustic transducer (EMAT), which works under the principle of acousto-elastic effect, called Lorentz force mechanism. EMATs are useful for non-contact ultrasonic nondestructive testing (NDT) of metallic materials for detecting defects and measuring thickness. A 2D finite element model of the spiral coil EMAT is developed to calculate the induced eddy current and the Lorentz force density inside the steel plate, implemented using the finite element package COMSOL Multiphysics®. This model is used to predict the performance of a spiral coil EMAT that generates plate waves and is compared with experimental data, as well as extended to analyze the interaction of plate wave modes with defects.