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...

Prediction of fatigue crack growth rates under variable loading using a simple crack closure model

A model for the prediction of growth rates of fatigue cracks in aluminium alloys subjected to service loading conditions is presented. The model is based on an approximate description of the crack opening behaviour and was applied successfully in an analysis of effects of crack growth acceleration and retardation observed experimentally under...