On the use of infrared thermography for the analysis of fatigue damage processes in welded joints

The paper presents an experimental approach for the analysis of localized fatigue damage processes during fatigue testing of welded steel structures by thermographic investigations of thermomechanical coupling phenomena. Special data processing of the recorded infrared sequences is proposed to separate linear and nonlinear damage-indicating effects. The method has been successfully applied to analyze the damage progress during fatigue testing of welded components. On the tested components localized damage processes could be observed as early as 10–30% of the total fatigue lifetime. The results confirm the high potential of the methodology for the determination of fatigue damage initiation. The technique provides a powerful experimental tool to investigate localized inhomogeneous damage and to analyze complex fatigue processes.