GEOMETRICALLY NONLINEAR-ANALYSIS OF ADHESIVELY BONDED DOUBLE CONTAINMENT CANTILEVER JOINTS

Under an increasing load, the adhesively bonded joints may undergo lar ge rotations and displacements while strains are still small and even all joint members are elastic. In this case, the linear elasticity the ory cannot predict correctly the nature of stress and deformation in t he adhesive joints. In this study, an attempt was made to develop an a nalysis method considering the large displacements and rotations in th e adhesive joints, assuming all joint members to be still elastic. An incremental finite element method was used in the application of the s mall strain-large displacement theory to the adhesively bonded joints. An adhesively bonded double containment cantilever (DCC) joint was an alysed using this incremental finite element method under two differen t loadings: a tensile loading at the horizontal plate free end, P-x an d one normal to the horizontal plate plane, P-y. The adhesive and plat es were assumed to have elastic properties, and some amount of adhesiv e, called spew fillet, that accumulated at the adhesive free ends was also taken into account. The analysis showed that the geometrical non- linear behaviour of adhesively bonded joints was strictly dependent on the loading and boundary conditions. Thus, a DCC joint exhibits a hig h non-linearity in the displacements, stresses, and strains in the cri tical sections of the adhesive and horizontal plate under a tensile lo ading at the free end of the horizontal plate, P-x, while a similar be haviour in these regions was not observed for a loading normal to the horizontal plate plane, P-y. However, an increasing non-linear variati on in the stresses and deformations of the horizontal plate appeared f rom the free ends of the adhesive-horizontal plate interfaces to the f ree end of the horizontal plate for both loading conditions. Consequen tly, joint regions with a low stiffness always undergo high rotations and displacements, and if these regions include any adhesive layer, th e non-linear effects will play an important role in predicting correct ly the stresses and deformations in the joint members, especially at t he adhesive free ends at which high stress concentrations occurred. In addition, the DCC joint exhibited a higher stiffness and lower stress and strain levels in the joint region in which the support and horizo ntal plate are bonded than those in the horizontal plate.