Fatigue damage in composites under different loading conditions

The damage development In notched (± 45, 0„, 90, 0-) carbon-epoxy coupon specimens tested under different loading conditions was determined. Constant amplitude tests at R = -1 and R = 0.1 as well as flight simulation tests were performed to establish those stress values for which no damage growth occurs.

Patch repair of corroded aircraft skin areas

Environmental conditions in Europe are conducive to corrosion attack of aircraft structures. In military aircraft corrosion problems occur especially at countersunk fastener holes. The corrosion is generally removed by grinding. A limited amount of material removal is specified by the aircraft manufacturers, but it is sometimes necessary to...

Engineering property comparisons of PM alloy X7091-T7E69 and IM alloy forgings

The engineering properties of PM alloy X7091-T7E69 forgings were compared with those of forgings of the IM alloys 7075-T73, 7175-T736, 7050-T736 and 7010-T736. The properties considered were: strength, fracture toughness, fatigue crack propagation under constant amplitude and flight simulation loading, stress corrosion crack initiation and...

Engineering property comparisons of the aluminium plate alloys 7050-T7365I, 7010-T7365I and 7010-T765I

The Al-Zn-Mg-Cu alloy 7050 produced by Alcoa is a typical plate and forging alloy because of its low quench sensitivity. In order to compare this alloy with the earlier tested plate alloy 7010 an experimental programme was performed involving tensile, fracture toughness, and fatigue testing. In addition stress corrosion crack initiation and...

The influence of different types of anodic layers on the fatigue properties of 202U-T3 and 7056-T6 sheet material

Constant amplitude and flight simulation fatigue tests have been carried out on sulphuric acid, chromic acid and phosphoric acid anodized specimens. A comparison was made with the fatigue behaviour of bare sheet material. Before fatigue testing the fracture strain of the anodic layers was determined.

Influence of corrosion damage on fatigue crack initiation

The influence of previous corrosion on fatigue crack initiation has been determined. Cylindrical specimens and flat specimens with a central hole of the aluminium alloy T075-T6 were corroded in a 3.5 % NaC1 solution. The cylindrical specimens were tested under constant amplitude loading while for the specimens with a central hole a block...