Interlaminar stresses and delamination of composite laminates under extension and bending

The metis element method (Hung 1978) has been applied to analyse free edge interlaminar stresses and delamination in composite laminates, which are subjected to extension and bending. The paper recalls Lekhnitskii?s solution for generalized plane strain state of composite laminate and Wang?s singular solution for determination of stress singularity order and of eigen coefficients Cm for delamination problem. Then the formulae of metis displacement finite element in two-dimensional problem are established. Computation of the stress intensity factors and the energy release rates are presented in details. The energy release rate, G, is computed by Irwin?s virtual crack technique using metis elements. Finally, results of interlaminar stresses, the three stress intensity factors and the energy release rates for delamination crack in composite laminates under extension and bending are illustrated and compared with<br />the literature to demonstrate the efficiency of the present method.