Development of an efficient methodology and tool to determine stress intensity correction factors for complex aircraft structures

Abstract

Damage tolerance analysis (DTA) of complex aircraft structures requires stress intensity correction factor (β-factor) solutions that cannot be accurately or practically determined with handbook solutions. Typically, these β-factors can be related to the load transfer to adjacent structures and to irregular geometries. A methodology based on ratios between stress intensity factors obtained from StressCheck finite element models is proposed to efficiently determine such factors, which can then be compounded with handbook solutions. Three CC-130 fatigue critical location examples are presented, showing that the results from the proposed methodology are in good agreement with those of other approaches and that the studied β-factors have an important impact on the total compounded stress intensity factor. Various approaches for calculating the β-factors for the complex structures are investigated. Finally, an automated parametric tool, which is able to efficiently generate special factors for typical aircraft critical locations, is presented.