Damage severity of monitored fatigue load spectra

Many military aircraft are used more severely and over a longer periodthan originally intended. Consequently, a careful life management, including service load monitoring has become indispensable. This paper describes the development of a simple method to quantify the severity in terms of "potential crack growth" of recorded load spectra. This...

Useful lifetime prediction software for plane semi-cracks in 3-D solid configurations

Computer programs are described to be used for fracture control purposes. Crack growth lifetimes can be predicted for plane cracks in 3-D structures. Values for stress intensity (K-) distributions at crack fronts are derived from data being available from literature for a restricted number of simple configurations. For arbitrary configurations...

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...