| on-Destructive Evaluation (NDE) methods are being used in aerospace industry to inspect flaws and damages for various materials including composites. An NDE method which is capable of detecting defects in C/C composites was developed. This method employs transient infrared thermography. The methodology, experimental setup, and the tests performed on both CAFS-CVI C/C and commercial C/C composites are presented in this thesis.;FEA modeling was used as a tool to refine measurements for the thermography system for a better understanding of the system. The modified flash thermography method, a unique method, was used. It combines both flash and step heating thermography methods into one by applying more heat than flash but at a shorter duration than step heating. Results show that drilled side hole defects with minimum size of 1.588mm in diameter at a depth of 1 to 2mm, and a maximum depth of 6 mm (12.7 mm in diameter) can be reasonably detected by this method. Blind hole defects with minimum size of 3.175mm in diameter at 2mm deep, and a maximum depth of 3mm (12.7mm in diameter) can also be detected. These results vary from types of C/C due to material make up and processing, as these affect the material properties. Based on the results, a unique transient thermography NDE method and setup to detect these defects in C/C composite materials costing... |
