Analytical solution of some delamination scenarios in thick structural sandwich plates

The first-order shear deformation plate theory is applied in this work to model thick rectangular sandwich plates with through-width delamination. The model is based on the concept of the four equivalent single layers and the system of exact kinematic conditions. Three different scenarios are considered: the failure of the core, the delamination between the top facesheet and the core, and finally, the case when the delamination takes place in the local midplane of the top facesheet. A general model is derived and applied to sandwich plates with Lévy type boundary conditions. The governing equations are summarized and the state-space model of the system is created. The mechanical fields are calculated and compared to finite element results. The comparison shows that the first order sandwich plate model is acceptable only in the case of the face-face delamination. The J-integral distribution is also calculated along the delamination front and it is concluded that the analytical model gives only a rough approximation of the results by finite element analysis and the virtual crack closure technique