ENERGYMETHOD OF TRIGONOMETRIC SERIES ABOUT THREEDIMENSIONALPROBLEMS OF INNER DELAMINATION IN COMPOSITE LAMINATES

By means of the principle of superposition, the stress state of a composite laminate with inner delamination is decomposed and the problem of delamination can be reduced to the analysis of an additional stress state of the original laminate subjected to additional shear load along the delamination surfaces. The trigonometric series is applied to describe the displacement mode satisfying the boundary conditions and the principle of minimum potential energy is used to determine the unknown coefficients of the above series. The convergency tests are carried out. From the computational results, it can be shown that all of the displacement components are convergent and the deflection converges more rapidly.