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.

Effect of penetrant on fatigue of aluminium alloy lap joints

The effect of penetrant on the fatigue life of single shear riveted lap joints was investigated by flight simulation fatigue tests using the MINITWIST gust spectrum. The penetrant/material combination investigated was ARDROX 985 P3T and aluminium alloy 202U-T3 sheet material (both bare and clad) respectively. The effect of penetrant on the...

The tail of the test spectrum: The effect of different approximations of the lower end of a gust load spectrum on crack growth and fatigue life in 7075-T6 and 2024-T3 specimens

The influence of the approximation of the lower end of the load spectrum was investigated by comparative tests using the Basic F-27 test programme and an extended version, containing three times more cycles per flight. Crack growth was studied on notched sheet specimens made of Alclad 202U-T3 and Alclad TOT5-T6. Fatigue life tests were done on...

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.

Effects of variations in gust spectrum and ground-load level on fatigue life and crack propagation in 70T5-T6 and 202U-T3 specimens

The effects of systematic variations in mean stress level and in spectrum and ground load severity of a flight simulation test programme have been investigated on riveted specimens (fatigue life) and sheet specimens with central saw cut (crack growth). The fatigue life and crack propagation life in Alclad 202U-T3 compared with Alclad TOT5-T6...

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...