An aging aircraft's wing under complex multiaxial spectrum loading: Fatigue assessment and repairing

The structural responses of an aging aircraft's wing due to operational loading cycles are determined using flight measurement. The stressing in the crack initiation locations in the chemically milled wing skin is a combination of compression, tension and shear. The uniaxial fatigue assessment and observed cracking behaviour indicates that the fatigue assessment should include the multiaxial loading effects. In this paper, the multiaxial fatigue effects are considered by combining the flight measurement results with FE method and engineering judgement. To avoid or repair the cracking of the chemically milled wing skin composite patching is presented for the reconstructive action.