Abstract
If small fatigue cracks initiated at welded structures are retrofitted by closing crack surface, it would lead to improving structural integrity with less cost. Fatigue tests were carried out on notched bead-on plates to develop a surface fatigue crack. Then, the sides of the crack were plastically deformed by impact tool to close the crack surface. With this treatment no fatigue crack growth was observed over ten million cycles of loading, otherwise only around two million cycles were needed for the crack to penetrate to plate thickness. The technique, named as Impact Crack Closure Retrofit Treatment, or ICR Treatment, may open the way to retrofit welded joints with small fatigue cracks.
