Mixed mode delamination in plates: a refined approach

Energy release rate and its mode partition in layered plates are analysed by using an improved laminated plate model. The adhesion between layers is modelled by means of a linear interface acting in the opening and sliding failure mode directions. Stress singularities at the crack tip are recovered when the stiffness of the interface approaches infinity. Kirchhoff or Reissner-Mindlin plate models are employed to describe the layers. Analytical solutions of the relevant governing equations are obtained through a variational formulation of an augmented total potential energy, in which the stiffness of the interface introduces kinematics constraints in the form of a penalty functional. Closed form solutions for energy release rates are given evidencing the effectiveness and the simplicity of the proposed model. Comparisons with fracture mechanics results-when available-are shown discussing the validity of the proposed mechanical model to predict mode partition. Interesting features emerging with the introduction of the layer-wise Reissner-Mindlin model are also highlighted, particularly with reference to coupling terms arising from shear effects. (C) 2001 Elsevier Science Ltd. All rights reserved.