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...

Een tweede serie orienterende geluidsvermoeiingsproeven op een triltafel

A second series of exploratory acoustic fatigue tests using a shaker. A second series of exploratory acoustic fatigue tests was carried out, again employing simple specimens mounted on a shaker. Strain measurements were compared with calculations. Crack growth initiated by a central notch was observed. A comparison was made between three types...

The effect of sheet edge working on the fatigue life under flight-simulation loading

Fatigue tests under flight-simulation loading have been performed on unnotched Alclad 2024-T3, anodised 2.0 mm thick sheet specimens, manufactured according to several machine-shop processes applied in the air craft industry. From the results it appears that milling is preferable to stamping. Rounding off the edges is also advantageous. The...

Environmental effects on crack grwoth in flight-simulation tests on 2024-T3 and 7075-T6 material Supplement: Compilation of test data from an investigation on the effect of environment on crack growth under flight-simulation loading

Flight-simulation tests based on a standardized gust load spectrum were carried out in normal air, very dry air and salt water. Specimen thicknesses were t = 2 mm and t = 10 mm, mean stress in flight was 70 or 55 MN/m². In all cases a significant effect of the environment was found. Fatigue lives for t = 10 ram were much shorter than for t = 2...

The significance of cladding for fatigue of aluminium alloys in aircraft structures

Flight-simulation tests were carried out on sheet specimens notched "by an open hole (Kt = 2.66). The material was 2024-T3 in three conditions; Alclad, bare and chemically milled. The crack initiation period and the crack propagation period were considerably shorter for the Alclad material. The significance of the cladding, both for constant...