Fig. 13: Comparison crack propagation process for two patched specimens under fatigue loading monitored from the metallic and the patched side
Understanding the interaction between local patch detachment and crack growth in the structure is one essential goal in the patch design process. To find out, how these two effects influence one another can lead to improved design methods. Therefore, additional investigations using optical LT are made for the specimen that is monitored from the patched side. A comparison of the thermal images gained from passive IrT and phase images resulting from LT measurements are displayed in Fig. 14.