Comparative Studies of GFRP Composites Using Pulsed Thermography and Transmission Terahertz Non-Destructive Testing Methods

Abstract

Composites are materials that have replaced traditional construction materials in numerous applications in various fields. Due to the possibility of creating the required material properties, fiber-reinforced composites are most often used. Despite competition from carbon and aramid fibers, the earliest glass fibers produced are used in many applications. One of the areas where glass fiber reinforced composites (GFRP) make a significant contribution to structural applications is aviation. Because both during production and operation, composites are exposed to damage, which often occurs in the internal structure of the composite, works are being carried out to develop the most effective method of non-destructive testing to detect such damage. The article presents a comparison of the results of non-destructive testing of glass fiber-reinforced composite samples. A comparison of the results of the possibility of detecting defects in the form of milled holes of different diameters and depths inside the samples was made. These damages are not optically visible on both surfaces of the samples. In non-destructive testing, infrared thermography and transmission terahertz methods were used. The obtained results indicate a great possibility of using terahertz radiation, especially in thicker structures of the GFRP composite, where thermographic methods are not as effective as in thin ones.