Detection of short cracks in riveted connections using Lock?In?Thermography

Although many riveted bridge structures made of old structural steel from the 19th and early 20th centuries are still in use today, there is usually no need to replace them. When assessing these with regard necessary refurbishment or strengthening measures, engineers information about remaining fatigue lifetime particular. Often sufficient life can be determined based on normative S-N-curve assessment. An initiation cracks has assumed. These occur primarily at edge rivet holes. In phase crack growth below head, cannot found a visual inspection structure. For this reason, cyclic fracture mechanics assuming start length beyond head. This paper reports investigations using thermoelastic stimulated Lock-In-Thermography as NDT method for detection hidden joints. The results have shown that heads detected. possible despite presence corrosion protection coating. detectable depends mainly level stress loading frequency.