Quantifying Hole-Edge Crack of Bolt Joints by Using an Embedding Triangle Eddy Current Sensing Film

Area of Science:

• Aerospace Engineering
• Non-Destructive Testing
• Electromagnetism

Background:

• Accurate quantification of hole-edge cracks in aircraft bolt joints is essential for structural integrity assessment.
• Existing eddy current sensor arrays face limitations in precisely determining crack parameters, particularly the crack angle.

Purpose of the Study:

• To introduce and evaluate a novel triangular eddy current sensor array for enhanced hole-edge crack quantification.
• To improve the accuracy in determining crack parameters, with a specific focus on crack angle, depth, and length.

Main Methods:

• Development of a new eddy current sensor array utilizing triangular coils instead of traditional rectangular coils.
• Optimization of the sensor array configuration, including excitation current directions and winding shape, through simulation.
• Validation of the sensor's performance using finite element simulations and experimental testing.

Main Results:

• The triangular coil configuration demonstrated superior sensor linearity and resolution compared to rectangular coils.
• Optimal performance was achieved with specific current direction configurations in circumferentially and axially adjacent coils.
• The sensing film proved effective in identifying crack depth and length with good accuracy.

Conclusions:

• The proposed triangular eddy current sensor array offers a significant advancement in quantifying hole-edge cracks in aircraft bolt joints.
• This technology shows strong potential for improving non-destructive evaluation and structural health monitoring in aerospace applications.