Fatigue strength reduction factors at rivet holes for aircraft fuselage lap joints

Abstract Fatigue test results to be utilized in a fatigue life prediction model for aircraft fuselage riveted lap joints are presented. A series of fatigue tests on aluminium alloy sheet coupons with an open hole and filled hole subjected to remote tension, pin loading and out-of-plane bending have been carried out. Such loading conditions were conceived to replicate local effects of the bypass load, transfer load and secondary bending respectively at the critical rivet row. It was shown that the fatigue response of the open hole specimens could be predicted with a satisfactory accuracy employing the Neuber fatigue notch factor. For the filled hole specimens considerably longer fatigue lives were observed than for the open hole specimens under the same type of loading; however, a reduction of the notch effect due to the hole filling was found to depend on the type of loading, interference magnitude and applied load level. A concept of utilizing the obtained results to quantitatively account in the fatigue life prediction model for filling the hole by the rivet shank, in addition to geometry parameters, is presented. Finally, consideration is given to load transmission by frictional forces and its implication for the fatigue properties of riveted lap joints.