Advances in Electromagnetic Acoustic Transducers Enhance NDE Capabilities

Strategic Insights -

Researchers at the Indian Institute of Technology Madras have developed electromagnetic acoustic transducers (EMATs) that can generate ultrasonic bulk waves and inspect metallic specimens at elevated temperatures. The new EMAT configurations enhance the Lorentz force and ultrasonic wave generation by optimizing the magnetic field in the region of eddy current generation. The study has the potential to improve the capabilities of non-destructive evaluation (NDE) techniques in challenging industrial environments.

Key Takeaways:

  • The research proposes the development of EMATs to generate ultrasonic bulk waves and inspect metallic specimens at elevated temperatures.
  • The new EMAT configurations enhance the Lorentz force and ultrasonic wave generation by optimizing the magnetic field in the region of eddy current generation.
  • Finite Element (FE) simulations were performed in aluminum samples to study the eddy current through varying coil widths, liftoffs, and static magnetic field intensity concentration.
  • The FE simulations revealed that eddy current intensity is independent of the coil widths.
  • Different EMAT configurations were designed and developed by concentrating the static magnetic field intensity in the region of the eddy current generation based on the simulation results.
  • Various EMAT configurations were fabricated and tested on 26 mm and 50 mm aluminum samples to measure their Signal-to-Noise Ratio (SNR).
  • The configuration with the highest SNR was further tested at elevated temperatures under proper insulation techniques.
  • The research concluded that these advancements have the potential to enhance the capabilities of NDE techniques in challenging industrial environments.
  • The study was conducted at the Indian Institute of Technology Madras and was peer-reviewed.
  • Vinay Mudapaka, Thulsiram Gantala, and Krishnan Balasubramaniam were involved in the research.
  • The study has been published in the journal Ultrasonics, with the paper titled "Development of bulk wave EMAT sensors with enhanced Lorentz force through magnetic field concentration in eddy current regions."

Statistics:

  • The research focused on the development of EMATs for generating ultrasonic bulk waves and inspecting metallic specimens at elevated temperatures.
  • 26 mm and 50 mm aluminum samples were used in the experimental study.
  • The Signal-to-Noise Ratio (SNR) was measured for various EMAT configurations.
  • The configuration with the highest SNR was further tested at elevated temperatures under proper insulation techniques.

Sources:

  • "Development of bulk wave EMAT sensors with enhanced Lorentz force through magnetic field concentration in eddy current regions." Ultrasonics, 2025;154:107687. Ultrasonics can be contacted at: Elsevier, Radarweg 29, 1043 Nx Amsterdam, Netherlands. (Elsevier - www.elsevier.com; Ultrasonics - www.journals.elsevier.com/ultrasonics/)
  • Indian Institute of Technology Madras. "Reports Findings in Science (Development of bulk wave EMAT sensors with enhanced Lorentz force through magnetic field concentration in eddy current regions)." Chemicals & Chemistry. June 13, 2025; p 1570.