Experimental Analysis of Digitized Frequency Modulated Thermal Wave Imaging for Non-destructive Testing and Evaluation of Materials

Thermal Wave Imaging (TWI) has gained wide acceptance in the field of Non-Destructive Testing and Evaluation (NDT&E) due to its reliable, remote, fast and quantitative characterization of various materials such as semiconductors, metals, composites, etc. The present work highlights the effectiveness of Digitized Frequency Modulated Thermal Wave Imaging (DFMTWI) technique for detection of sub-surface defects in a specimen. The capability of the proposed technique has been compared with the popular pulse based and mono-frequency thermal excitation schemes by carrying out an experimental study over a specimen containing Flat Bottom Hole (FBH) defects.