Using square wave inductive thermography techniques to monitor the dynamic growth of cracks in steel welded structures

Monitoring crack growth is essential for maintaining steel structures subjected to cyclic loading, such as bridges, cranes, offshore platforms, and wind energy towers. A reliable crack detection method ensures the timely identification of crack initiation and propagation in critical structural components, allowing for necessary repairs or restorations before they cause service interruptions, accidents, or structural failures. This paper presents a real-time crack detection system based on inductive thermography to monitor crack growth in an SM490 steel welded specimen under cyclic loading. The system operates by generating eddycurrents, which inducelocalized heating at the crack tips. This temperature increase is captured using an infrared (IR) camera, and the analysis of IR images enables precise identification of crack location and growth in real time. Additionally, the system is highly efficient, with a low power consumption of only 200 W, making it a practical and effective solution for on-site crack monitoring. These characteristics emphasize its strong potential for non-destructive testing (NDT) applications.