Development of internal defect detection equipment for composite materials based on shear speckle interference.

Area of Science:

• Materials Science
• Optical Engineering
• Nondestructive Testing

Background:

• Traditional composite defect detection systems suffer from slow phase-shifting speeds and limited hardware integration.
• Shear speckle interferometry is a powerful technique for defect detection but can be limited by processing speed and noise.

Purpose of the Study:

• To develop a portable, high-speed composite defect detection system overcoming traditional limitations.
• To improve real-time phase unwrapping algorithms for enhanced shear speckle interferometry measurements.

Main Methods:

• Integration of a Wollaston prism shearing module with a high-speed liquid crystal phase retarder.
• Development of an embedded GPU platform for accelerated processing.
• Implementation of a novel phase unwrapping algorithm combining gradient-adaptive smoothing and graph-cut optimization.

Main Results:

• The new algorithm reduced root mean square error (RMSE) by 27.34%–33.20% under hybrid noise conditions.
• Single-frame analysis was completed within 0.36 seconds.
• Achieved 97% accuracy in detecting internal defects (≥2mm diameter) in aluminum and composite specimens under heat loading.

Conclusions:

• The developed portable device offers high-speed, high-sensitivity nondestructive testing capabilities.
• The integrated hardware-software design provides submillimeter resolution and field-deployable portability.
• This system meets critical requirements for aerospace applications demanding efficient defect detection.