Analysis of Stress Distribution in Simple Glued Lap Joints under Shear Load
Satoki KOHNO, Okitsugu SAKATA, Akira KIKUCHI, Kazutoyo KAWANO, Yoshibumi KINOSHITA, Kohichi MIYASHITA
This study used the Finite Element Method, modeled after shear load tension tests of simple glued lap joints, to analyze the stresses on the joints. By investigating the area of stress concentration, this study analyzed the characteristics and problems of this test. First, because of the way the joints were formed, when the joints were placed under a constant shear load, bending moment occurred and unique deformation characteristics resulted. The study showed that it was necessary to make the support portions as long as possible and the indented portions (which were not overlapped) as short as possible; this minimized the bending moment effects and made it possible to obtain comparatively pure shear strength results. Second, after analyzing the relationship between adhesive thickness and stress distribution we found that, (1) stress concentrations primarily existed at the both edges of the adhesive layer, (2) the stress concentration was greatest near the adhesive/adherent interface, and (3) in order to avoid stress concentration the adhesive layer should be thicker. The same investigation was undertaken to determine changes in Young's Modulus Ea related to adhesives. The results indicated that the smaller the Ea the greater the stress distribution. Further, the change in t and Ea, when considering the surface elasticity and stiffness of the joint, indicated that the same effects were produced in terms of stress concentration.
Key words : Adhesive Joint, Shear Test, Finite Element Method, Bending Moment, Adhesive Layer Thickness, Young's Modulus