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An analytical model for determining adhesive stress distributions within the adhesive-bonded single-lap composite joints was developed. ASTM D3165 ‘‘Strength Properties of Adhesives in Shear by Tension Loading of Single-Lap-Joint Laminated Assemblies’’ test specimen geometry was followed in the model derivation. In the model derivation, the composite adherends were assumed linear elastic while the adhesive was assumed elastic-perfectly plastic following von Mises yield criterion. Laminated Anisotropic Plate Theory was applied in the derivation of the governing equations of the bonded laminates. The adhesive was assumed to be very thin and the adhesive stresses are assumed constant through the bondline thickness. The entire coupled system of equations was determined through the kinematics relations and force equilibrium of the adhesive and the adherends. The overall system of governing equations was solved analytically with appropriate boundary conditions. Computer software Maple V was used as the solution tool. The developed stress model was verified with finite element analysis using ABAQUS by comparing the adhesive stress distributions.

Based on the laminated anisotropic plate theory, an analytical model is proposed to determine the stress and strain distributions of adhesive-bonded composite single-lap joints under tension. The laminated anisotropic plate theory is applied 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. Based on the proposed model, the stress and strain distributions of the adherends and the adhesive can be predicted. The coupling effect between the external tension and the induced bending due to the asymmetry of composite laminates are also included. The two adherends can also have different materials and properties. An existing FEA code, “ALGOR,” is used as a comparison with this proposed analytical model. Results from this developed model are also compared with Goland and Reissner’s as well as Hart-Smith’s papers.

Several important issues regarding damage simulation of composite laminates due to low velocity impact were investigated including contact law, damage initiation and the corresponding change of stiffness, and damping. Continuum damage mechanics was applied to account for the change of mechanical properties of damaged materials. The Hertzian contact law was modified in order to accommodate the serious damage in the plate. A semi-empirical delamination damage criterion was introduced. A finite element program was written in FORTRAN using twenty-noded solid elements with layered structure to analyze the transient dynamic response of composite laminates. In the simulation computations, variable material damping coefficients were applied to the elements according to damage in order to stabilize the computation. Damage in the forms of matrix cracking, delamination, and fiber breakage were included and analyzed. Results including the force history and delamination areas were found to correlate well with the experiments.

A model for predicting the contact duration, force, indentation, and displacement under impact has been developed for impact of a composite laminated plate with a hemispherical indenter. The governing equations were first proposed and then solved with the initial conditions along with the peak force condition. An expression for each parameter has been obtained in a simple expression through straightforward derivation. Both static and dynamic tests have been conducted. Ten impact tests were conducted using a weight drop tower tester. Comparison between the model predictions and the experimental data on the impact duration and impulse are provided, and were found to be within 14% for all tests involved. Comparison of the impact force-history also shows good accord.

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