| Abstract | An elastic deformation analysis of bonded composite butt joints in tension was carried out. Theoretical expressions of the effective Young’s modulus and bending stiffness for laminated composite beam panels were derived under both plane-strain and plane-stress conditions. Secondary bending deformation for bonded composite butt joints was analyzed theoretically. Joint elongation was estimated using a theoretical expression presented herein. An approach was proposed to eliminate the strain discontinuity at the joint overlap end, an artifact of inappropriate use of the Euler–Bernoulli beam theory. Expressions for the four coefficients arising from the coupled adhesive stress differential equations used were provided, and two strategies were proposed to explore the complete closed-form adhesive stress solutions in a general composite butt joint configuration. Two butt joint cases are presented. The case 1 joint was fabricated using identical laminated composite panels for both the adherends and the doubler, while the thickness of the doubler of the case 2 joint was 50% thicker. Three-dimensional finite element models were created for analysis of the unit-width joints under a plane-strain condition. Good agreement for the predicted joint deformation (deflection, elongation, and strain) was achieved between the three methods. Finite element results showed that high peak adhesive stresses were developed at the inner overlap edge area, and they suggested that appropriate reinforcement should be made in this region to ensure structural integrity. |
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