Crack arresting capability is experimentally examined using center cracked tension specimens and varying the placement of the dimple ahead of the crack tip. It is confirmed that the dimple gives a greater crack arrest effect than that of the stop hole method. Next, the fatigue life of smooth specimens is compared, both with and without dimples. It is indicated that the dimple has a benefit only to the repair case after the crack is initiated. Finally, stress intensity factors of a crack due to a dimple are numerically evaluated, and a guiding principle is clarified for placing dimples.

Keywords:
aluminium alloys, sheet materials, crack-edge stress field analysis, fatigue cracks, fatigue testing, crack detection, internal stresses, numerical analysis, Crack Arrest, Crack Growth, Dimple, Fatigue Life, Pinching Force, Stop Hole, Stress Intensity Factor
Topics:
Fracture (Materials), Stress, Fatigue life
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 by ASME
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