• Damnjanović, Vesna
• Karkalic, Radovan
• Jovanovic, Dalibor
• Kovacevic, Branko
• Radakovic, Sonja
• Tomic, Ljubisa
• Filipovic, Dalibor

Abstract

<jats:p>Nondestructive thermal examination can uncover the presence of defects viatemperature distribution profile anomalies that are created on the surface asa result of a defect. There are many factors that affect the temperaturedistribution map of the surface being tested by Infrared Thermography.Internal defect properties such as thermal conductivity, heat capacity anddefect depth, play an important role in the temperature behavior of thepixels or regions being analyzed. Also, it is well known that other externalfactors such as the convection heat transfer, variations on the surfaceemissivity and ambient radiation reflectivity can affect the thermographicsignal received by the infrared camera. In this paper we considered a simplestructure in the form of flat plate covered with several defects, whosesurface we heated with a uniform heat flux impulse. We conducted atheoretical analysis and experimental test of the method for case of defectson an aluminum surface. First, experiments were conducted on surfaces withintentionally created defects in order to determine conditions and boundariesfor application of the method. Experimental testing of the pulsed flashthermography (PFT) method was performed on simulated defects on an aluminumtest plate filled with air and organic compound n-hexadecane, hydrocarbonthat belongs to the Phase Change Materials (PCMs). Study results indicatethat it is possible, using the PFT method, to detect the type of materialinside defect holes, whose presence disturbs the homogeneous structure ofaluminum.</jats:p>

Topics

• impedance spectroscopy
• surface
• compound
• phase
• experiment
• aluminium
• organic compound
• defect
• thermal conductivity
• heat capacity
• thermography