Some tests to assess the effect of crack stoppers on the fatigue life of centre-notched sheetspecimens

Several simple crack stopping methods were evaluated In fatigue crack propagation tests on 2024-T3 Alclad sheet specimens. After precracklng until a crack of 40 mm was obtained crack stoppers were Installed and the fatigue test was continued. Crack stoppers Installed In stop holes were: a blind rivet, a hard driven rivet, a heavily tightened...

Flight simulation fatigue tests on lugs with holes expanded according to the split-sleeve cold work method

Flight simulation tests on 2024-T3 and 7075-T6 lug specimens indicated significant fatigue life improvements obtained by expanding the holes in accordance with the split-sleeve cold work method. Geometrical distortions induced by the expansion were measured. The significance of residual stresses is analysed with reference to depth of penetration...