Research on gear defect detection using electromagnetic induction eddy current and infrared thermography

• A non-destructive testing method for detecting gear defects is presented, leveraging electromagnetic induction eddy current infrared thermography . • A multi-physics numerical model is established to analyze the characteristic responses of gear surfaces using excitation coils with diverse structures. • An experimental platform validates the method’s effectiveness in detecting and quantitatively assessing gear defects at various locations and depths. During the processing, manufacturing, and service life of gears, defects such as cracks may appear both on the surface and within the interior due to external factors or material properties. Consequently, gear inspection and safety evaluation are of critical importance. This paper presents a non-destructive testing method for detecting gear defects based on electromagnetic induction eddy current infrared thermography, which integrates key principles such as electromagnetic induction and Joule’s law. By designing excitation coils with different structures, a multi-physics numerical model of the detection system is established to observe the characteristic responses of the gear surface. On this basis, the study analyzes the effects of defect location, depth, and burial position on the detection results. The findings indicate that the temperature response on the gear surface is influenced by the distribution of induced eddy current density, induced current interaction with defects, and the heat transfer mechanism. To validate the effectiveness of this detection method, an experimental platform is constructed. Results confirm that the proposed method can simultaneously detect defects at various locations on the gear surface and quantitatively assess defect depths up to 4 mm and burial depths up to 1.3 mm from the surface. The induced eddy current heating allows for one-time imaging of the entire gear surface, providing intuitive and clear visualization of defect shapes, sizes, and depths. This method significantly enhances the scope of comprehensive non-destructive testing technologies by utilizing multi-physics coupling.