Analysis of the effects of thin sealant layers in aircraft structural joints

A general method is devised for determining the effects of thin layers of sealants or adhesives on the mechanical behavior of riveted lap joints using finite element analysis. The resulting method, thin adhesive layer analysis (TALA), models the sealant layer with normal and shear spring elements. The TALA method is validated by comparison with existing solutions for both linear high-modulus, and nonlinear low-modulus, adhesives. It is then used to model sealants for aircraft-riveted lap joints. The analyses reveal that sealant layers introduce large increases in the in- and out-of-plane displacements, reduce bending and stress concentration factors (SCF), and increase the fatigue life of riveted lap joints.