Effect of rolling texture on bearing capacity of aircraft repair patches and replaced panels

The article combines issues related to biaxial fatigue loading, corrections for equivalent stress calculations, and the practical application of new knowledge regarding biaxial fatigue in the aviation industry. It considers the possibility and expediency of taking into account the anisotropy of metals’ mechanical characteristics in aircraft repair procedures, such as patching and replacing damaged skin panels. The biaxial loading of the skin is shown to be a significant factor that should be considered in the aircraft skin repair process. It is shown that while well-known Huber-Mises formula works well for isotropic materials, the fuselage skin made of anisotropic alloys requires corrections to the Huber-Mises method. For aircraft parts subjected to biaxial loading, the assessment of equivalent uniaxial stresses can be done by introducing the crystallographic factor into the Huber-Mises formula. This is achieved by transforming the biaxial stress components of fuselage loading due to pressurization and bending into the resolved stresses in the activated crystallographic slip systems of the dominant texture.