A novel high sensitivity sensor for remote field eddy current non-destructive testing based on orthogonal magnetic...

Area of Science:

• Non-destructive testing
• Electromagnetism
• Materials science

Background:

• Conventional remote field eddy current testing (RFECT) has limitations in signal-to-noise ratio and sensitivity to axial cracks in ferromagnetic tubes.
• Existing sensors struggle to detect subtle defects, impacting structural integrity assessments.
• Improved non-destructive testing (NDT) methods are crucial for reliable inspection of critical infrastructure.

Purpose of the Study:

• To develop a novel high-sensitivity sensor for RFECT of ferromagnetic tubular structures.
• To overcome the limitations of conventional sensors, particularly for detecting axial cracks.
• To enhance the overall effectiveness and reliability of NDT for tubular components.

Main Methods:

• Three-dimensional finite element simulation to analyze the remote field effect under orthogonal magnetic field excitation.
• Optimization of key parameters including frequency, exciting currents, and shielding modes.
• Design and analysis of various pick-up coils, including a novel self-differential mode pick-up coil.
• Experimental verification using a ferromagnetic tube with manufactured defects.

Main Results:

• The proposed sensor demonstrates significantly improved sensitivity for defect detection, especially for axial cracks shallower than 40% of the wall thickness.
• The orthogonal magnetic field excitation effectively enhances the remote field effect.
• A self-differential mode pick-up coil provides nearly equal sensitivity across different defect types.
• Experimental results validate the simulation findings and the sensor's performance.

Conclusions:

• The novel high-sensitivity sensor based on orthogonal magnetic field excitation is effective for NDT of ferromagnetic tubes.
• The sensor offers superior detection capabilities for critical defects like shallow axial cracks.
• The developed sensor technology advances the field of non-destructive testing for industrial applications.