Fast Terahertz Reflection Imaging for In-Line Detection of Delaminations in Glass Fiber-Reinforced Polymers.

Area of Science:

• Materials Science
• Non-destructive Testing
• Terahertz Technology

Background:

• Terahertz (THz) technology is emerging for non-destructive inspection of polymer inner structures.
• Industrial applications require adapted THz imaging systems and more application studies.
• Glass fiber-reinforced polymers (GFRPs) are widely used but can develop defects.

Purpose of the Study:

• To present a fast and flexible THz imaging system for industrial applications.
• To demonstrate the system's capability in investigating defects in GFRPs.
• To specifically detect drilling-induced delaminations in GFRPs.

Main Methods:

• Developed a THz imaging system with integrated hardware and software.
• Acquired 3D volumetric data by raster scanning GFRP samples.
• Compared THz images with X-ray computed tomography (XCT) reference data.

Main Results:

• THz imaging successfully identified artificial defects (aluminum and Teflon inlays).
• The system detected real defects, including drilling-induced delaminations in GFRPs.
• Volumetric THz images provided detailed defect visualization.

Conclusions:

• The presented THz imaging system is suitable for non-destructive testing of GFRPs.
• THz imaging can reliably detect critical defects like delaminations in industrial settings.
• This technology holds significant potential for quality control in polymer composite manufacturing.