دانلود رایگان مقاله تشخیص آسیب تاثیر بر مواد کامپوزیت توسط تصویربرداری تراهرتز

Abstract

This paper presents a Non-Destructive Testing (NDT) method based on the penetration properties of terahertz (THz) waves. A CW raster-scanning THz imaging setup, using a 3.8 THz Quantum Cascade Laser as a source, is used to perform NDT of polypropylene/polypropylene composite samples. Results from transmission and reflection THz imaging are compared to ultrasound C-scan. THz images in reflection give similar results to C-scan whereas THz transmission.

5. Conclusion

Impact damage detection on composite fiber polypropylene/polypropylene plates was performed by THz imaging in transmission and in reflection. The results were compared with ultrasonic C-scan NDT, followed by microscopic observation of induced damage. The C-scan reveals damage parallel to the plate, thus delamination. In the case of unidirectional laminates, this damage is sharp and flat and as such it is easily detected by C-scan. In the case of fabrics, where the damage is more complex with cracks between pleats but also in the fold, between the two directions of weave called meta-delamination [18], the C-scan gives an indication about the damaged area but without specifying the nature and location of the damage. The THz reflection reverse side appears to give the same indication as the C-scan while the THz transmission appears to highlight the fiber cracks. The two THz imaging techniques are complementary and can provide a NDT with information about the location and type of the damage, crucial for understanding damage in composite structures.