Finite Element Analyses of Structural Stresses near Dissimilar Spot Joints in Lap-Shear Specimens 2019-01-1112
Structural stress distributions near rigid, nearly rigid, dissimilar and similar spot joints in lap-shear specimens are investigated by three-dimensional finite element analyses. A set of accurate closed-form structural stress solutions is first presented. The closed-form structural stress solutions were derived for a rigid inclusion in a square thin plate under various loading conditions with the weak boundary conditions along outer edges or semi-circular boundaries by satisfying the equilibrium conditions. Finite element analyses with different joint material behaviors, element types and mesh designs are conducted to examine the structural stress solutions near the rigid, nearly rigid, dissimilar and similar spot joints in lap-shear specimens. The results of the finite element analyses indicate that the computational structural stress solutions on the edge of the joint depend on the joint material behavior, element type, and mesh design but the solutions do not significantly depend on the joint material behavior, element type, and mesh design at the radius distance of one or two joint radius away from the joint where fatigue failures of mechanical joints such as flow drill screw and self-piercing rivet joints may occur.