Digitised Frequency Modulated Thermal Wave Imaging for Non-destructive Testing and Evaluation of Glass Fibre Reinforced Polymers

The active thermal non-destructive testing and evaluation techniques have gained wide acceptance in health monitoring of various solids materials such as metals, composites and semiconductors. The most popular active infrared thermographic methods for non-destructive testing and evaluation applications are pulse based thermography and lock-in thermography techniques. But the usage of these techniques is limited due to their inherent limitations. To overcome the limitations of the existing approaches, the present work demonstrates the effectiveness of digitized frequency modulated thermal wave imaging technique for detection of different shaped defects in a glass fibre reinforced polymer specimen. Further, the usage of post-processing scheme facilitates defect detection with high resolution and also preserves the shape of defects.