Research on Alternating Current Field Measurement Method for Buried Defects of Titanium Alloy Aircraft Skin

Area of Science:

• Materials Science
• Aerospace Engineering
• Non-Destructive Testing

Background:

• Titanium alloys are critical for aerospace components like engines and structures.
• Aircraft skins face degradation from corrosion and stress, leading to cracks and defects.
• Effective detection of these defects is crucial for flight safety.

Purpose of the Study:

• To design and validate an alternating current field measurement (ACFM) probe for detecting surface and buried defects in thin-walled titanium alloy plates.
• To investigate the impact of defect characteristics and excitation frequency on ACFM signals.
• To optimize the ACFM probe for enhanced sensitivity and reliability in detecting flaws in aircraft skins.

Main Methods:

• Development of an ACFM detection probe based on alternating current field measurement principles.
• Establishment of a finite element simulation model using COMSOL 5.6 for TC4 titanium alloy plates with buried defects.
• Systematic investigation of defect length, depth, and excitation frequency effects on characteristic ACFM signals.
• Optimization of the detection probe design through simulation and experimental validation.

Main Results:

• The ACFM probe demonstrated high sensitivity to varying lengths and depths of buried defects.
• Successfully detected small cracks (3 mm length, 2 mm depth) and deeper flaws (10 mm length, 4 mm depth).
• Simulation and experimental data confirmed the probe's effectiveness in identifying subsurface flaws.

Conclusions:

• The designed ACFM probe is a viable tool for detecting both surface and buried defects in thin-walled titanium alloy structures.
• The study confirms the probe's capability to identify critical flaws in aircraft skins, enhancing safety and maintenance protocols.
• This ACFM technology offers a promising solution for non-destructive evaluation in the aerospace industry.