Stress-Strain Analysis of Adhesive-Bonded Composite Single-Lap Joints Under Various Loadings.

The objective of this study is to develop mathematical relations for stress and strain distributions of adhesive-bonded single-lap joints under cylindrical bending and tension. Based on the Theory of Mechanics of Composite Materials and Anisotropic Laminated Plate Theory, elastic models are proposed to predict the stress-strain distributions of the laminates and the adhesive under cylindrical bending and tension. A simplified elastic-plastic model is also recommended for the case of tension loading. For each case, the Laminated Anisotropic Plate Theory is first used in the derivation of the governing equations of the two bonded laminates. The entire coupled system is then obtained through assuming the peel stress between the two laminates. With the Fourier series and appropriate boundary conditions, the solutions of the system are obtained. In this analytical study, the effects due to the transverse shear deformation as well as the coupling effects of external tension and bending of an asymmetric laminate are included. These developed elastic models are compared to the finite element models. An existing finite element analysis code, ALGOR, is used as a comparison with these developed elastic models. Results from the developed model for tension are also compared with Goland and Reissner and Hart-Smith\u27s theories. Based on the developed models, the effects of the overlay length and laminate properties on the maximum adherend and adhesive stresses under both cylindrical bending and tension are evaluated