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Updated: Jun 15, 2026
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Crack Monitoring in Resonance Fatigue Testing of Welded Specimens Using Digital Image Correlation
Published on: September 29, 2019
Summary
A novel optical Fourier spectrum analyzer system detects tiny, 0.5 micrometer fatigue cracks in titanium. This advanced technique uses laser light diffraction patterns for reliable crack signature analysis without precise focusing.
Area of Science:
- Materials Science
- Optical Physics
- Non-Destructive Testing
Background:
- Fatigue cracks in titanium alloys pose significant risks in various engineering applications.
- Early detection of micro-cracks is crucial for ensuring structural integrity and preventing catastrophic failures.
- Current detection methods may require complex procedures or lack sensitivity for micro-scale defects.
Purpose of the Study:
- To introduce and validate a 1-D optical Fourier spectrum analyzer system for detecting small fatigue cracks in titanium.
- To demonstrate the system's capability in identifying micro-cracks with high sensitivity.
- To analyze the optical signatures generated by surface cracks and understand their underlying physics.
Main Methods:
- Utilizing a 1-D optical Fourier spectrum analyzer system.
- Scanning reflected laser light diffraction patterns from titanium test samples.
- Employing analytic modeling of crack surface profiles to interpret optical signatures.
Main Results:
- Successfully detected fatigue cracks as small as 0.5 micrometers in titanium.
- Observed distinct signature features in diffraction patterns correlated with the presence of surface cracks.
- Demonstrated robustness of signature characteristics, unaffected by critical focusing or precise optics-to-sample positioning.
Conclusions:
- The 1-D optical Fourier spectrum analyzer is a sensitive and robust tool for detecting micro-scale fatigue cracks in titanium.
- Laser light diffraction pattern analysis provides reliable signatures for crack identification.
- Analytic modeling effectively explains the observed optical phenomena related to crack surface profiles.
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