Publication

Abstract : Thermal barrier coatings for the objects operating at elevated temperatures require proper non-contact condition monitoring to avoid catastrophic failures. Thermal wave imaging is evolving as a reliable testing mechanism to cater to these types of industrial applications. Among various flaws, non-uniform thickness variations occur either during the manufacturing process or during the operational period. In present work, a numerical simulation is carried out to model a thermal barrier coatings sample with wedge shaped structure excited by quadratic frequency modulated (QFM) heat flux. The quantitative and depth resolution capability of QFMTWI over thermal barrier coating is analyzed using pulse compression and provided an empirical model for thickness estimation. Further, the enhanced detection of thickness variations with reduced dimensionality is achieved by employing proper orthogonal decomposition (POD) over pulse compression sequence.