Mixed mode delamination in plates: a refined approach

Energy release rate and its mode partition in layered plates are analysed b y using an improved laminated plate model. The adhesion between layers is m odelled by means of a linear interface acting in the opening and sliding fa ilure mode directions. Stress singularities at the crack tip are recovered when the stiffness of the interface approaches infinity. Kirchhoff or Reiss ner-Mindlin plate models are employed to describe the layers. Analytical so lutions of the relevant governing equations are obtained through a variatio nal formulation of an augmented total potential energy, in which the stiffn ess of the interface introduces kinematics constraints in the form of a pen alty functional. Closed form solutions for energy release rates are given e videncing the effectiveness and the simplicity of the proposed model. Compa risons with fracture mechanics results-when available-are shown discussing the validity of the proposed mechanical model to predict mode partition. In teresting features emerging with the introduction of the layer-wise Reissne r-Mindlin model are also highlighted, particularly with reference to coupli ng terms arising from shear effects. (C) 2001 Elsevier Science Ltd. All rig hts reserved.