Effect of interference and location of the crack on the Stress Intensity Factor for the 3-2-1 Lozenge pattern riveted joint

Abstract

The effect of crack size and pin-hole interference on the stress intensity factor in strap plates of a 3-2-1 Lozenge pattern riveted butt joint is discussed in this paper. A 2-D plane stress finite element analysis using ANSYS® was employed to understand the load sharing pattern at the joints in the presence of cracks and as a consequence, on the stresses and the stress intensity factor. Five different interference levels were considered to identify the optimal level of interference that reduces the stress intensity factor. The cracks were introduced in various combinations at the rivet holes of Lozenge pattern joint and its effect on stress intensity factor was examined. For a crack propagating from a joint at one extreme to the joint at the other extreme, 0.15% interference was found to be the most beneficial interference level, with a reduction of SIF by up to 11.46%. For a crack propagating symmetrically from the joint at the center towards the rivets at both extremes, an interference level of 0.1% had the most beneficial impact, reducing the SIF by up to 20%. In the presence of cracks at multiple joints, the SIF at a given joint is influenced significantly by the size of cracks at the neighboring joints than the size of crack at that joint.