Automated Foreign Object Detection for Carbon Fiber Laminates Using High-Resolution Ultrasound Testing

Area of Science:

• Materials Science
• Non-Destructive Testing
• Aerospace Engineering

Background:

• Carbon fiber laminates offer excellent properties but are susceptible to manufacturing defects like foreign object debris (FOD).
• Such defects act as stress concentrators, potentially leading to premature part failure.
• Effective detection and quantification of FOD are critical for quality control in manufacturing.

Purpose of the Study:

• To develop and validate a high-resolution pulse-echo ultrasound testing method for detecting and quantifying FOD in carbon fiber laminates.
• To demonstrate the capability of a portable, out-of-immersion tank ultrasound system for this application.
• To assess the accuracy of the method in identifying FOD dimensions and depth.

Main Methods:

• Utilized a portable, out-of-immersion tank, high-resolution pulse-echo ultrasound scanning system.
• Generated high-resolution C-scans from full-waveform datasets.
• Employed an automatic edge detection technique to extract FOD depth and planar dimensions.
• Used CT imaging for verification of FOD placement and integrity.

Main Results:

• Successfully detected all embedded foreign objects, including those typically considered undetectable.
• Accurately identified the layer depth of the FOD.
• Achieved a typical error of less than 1.5 mm for the primary dimension of the detected FOD.
• Validated detection for circular and triangular FOD shapes within specified size ranges.

Conclusions:

• The developed high-resolution ultrasound method is effective for detecting and quantifying FOD in carbon fiber laminates.
• The portable system provides capabilities comparable to full immersion systems, enabling field applications.
• This technique enhances quality control by reliably identifying critical manufacturing defects, improving structural integrity and safety.