Stress Intensity Determination for MSD Riveted Stiffened Panels in the Presence of Corrosion

Abstract

Accurate stress intensity solutions for multiple site damage (MSD) cracks in riveted stiffened panels are difficult to determine due to geometric complexity along with variations in rivet load transfer and corrosion, especially the interaction of MSD cracks. A methodology was proposed for efficiently depicting rivet in stiffened panel using finite elements. Rivet material properties were determined based on an empirical force-displacement relationship, for highly refined rivet model as well as for idealized spring element representations of rivets. Parametric studies of panels with a middle crack and a central stiffener indicate that rivets can provide comparable load transfer and relative displacement if the rivets closed to the crack are explicit modeled. Using idealized combination of explicitly and spring element representations of rivets, the stress intensity factors (SIFs) for uncorroded and corroded one-bay stiffened panels were predicted. The results show that the effect of MSD and thinning of the sheet is to increase substantially SIFs values compare to that of a single crack without corrosion. But the SIF is insensitive to corrosion of stiffener. The particular rivet material has relatively little effect on SIF values, while the rivet diameter has a significant effect.