A numerical approach for testing and evaluation of mild steel material by thermal wave imaging

Abstract

Among the widely used active infrared non-destructive testing and evaluation methods, coded thermal wave imaging modalities have proved to be an efficient testing and evaluation methods for characterization of various solid materials. These techniques makes use of relatively low peak power heat sources in a moderate time compared with the conventional pulsed based and sinusoidal modulated thermographic approaches respectively. This present work introduces a 11-bit Barker coded thermal wave imaging approach for characterization of mild steel sample having flat bottom holes as defects. Capabilities of the proposed approach has been studied on a mild steel sample containing flat bottom holes as sub-surface defects located at different depths and it has been modeled using a finite element method. Results show the defect detection capabilities of the proposed 11-bit Barker coded excitation scheme as a promising testing and evaluation method to detect the subsurface defects.