Abstract:

ESDU 79024 describes the analysis of the cumulative frequency loading spectrum in preparation for the damage calculation. The data for cumulative frequency gust and manoeuvre loading are obtained from ESDU 69023 and for the ground manoeuvre loading from ESDU 75008. A method is suggested for deriving the ground-air-ground cycle, which is the most damaging in the wing loading spectrum, and the method of extracting that from the other cumulative frequency data is explained. The residual up-gust and manoeuvre and ground manoeuvre spectra follow. The problem of incorporating local loads due to undercarriage or flap tracks is discussed. A comprehensive worked example illustrates the application of the method to providing a life estimate for a wing lower skin joint.