Effects of rivet hole arrangement on fatigue performance of thin sheets for fuselage: DIC and numerical calculation

Abstract

The fatigue performance and fracture mechanics of 2198-T8 Al-Li thin sheet with multi-diameter rivet holes were studied experimentally and numerically, which is mainly used in the new generation of C919 aircrafts. Firstly, the fatigue crack propagation mode under uniaxial fatigue load was investigated based on digital image correlation and virtual extensometer. Then, the Stress Intensity Factor (SIF) formula was modified and the applicable range was determined based on the tests and finite element method simulation results for the specimen with single rivet hole. Finally, the modified SIF formula was applied to predict the fatigue life of specimen with multi-diameter rivet holes. The results show that the crack propagation mode transforms from mode I to mode I+II, and the modified SIF formula could be used to obtain a more conservative fatigue result for single rivet hole when the angle of pre-crack is less than 5°. For the specimen with multi-diameter rivet holes, the fatigue life decreases with the rise of diameter of the larger rivet hole Φ1, and it also decreases with the increase of difference between larger and smaller hole Φ1−Φ2 when larger diameter Φ1 is constant. The fatigue life of HH-type specimen is generally smaller than that of the SS-type under the same rivet hole arrangement. The prediction result is conservative with a maximum relative error less than 7.0%