Investigation of electromagnetic acoustic transducer efficiency with composite magnetisation direction magnets

This study investigates Electromagnetic Acoustic Transducers (EMATs) efficiency with composite magnetisation direction magnets. EMATs are an essential technology for non-destructive testing (NDT) in industrial applications, offering advantages such as non-contact operation and suitability for harsh environments. However, the application of EMATs is often limited by weak testing signals. This research explores the optimisation of bias magnetic fields through various magnet arrangements to enhance transduction efficiency. The study uses finite element simulations to compare magnetic field distributions and their effects on EMAT performance for different magnet configurations, including periodic permanent magnets (PPM), ring-type magnets, and Halbach arrays. Results indicate that specific composite magnet configurations can significantly improve both the normal and tangential magnetic flux density, thereby increasing the strength of the generated and received ultrasonic waves. This optimisation of the bias magnetic field is crucial for advancing EMAT technology and improving testing accuracy in industrial NDT applications.