Assessment of the geometrically nonlinear behavior of thin cleavage type surface defects of anisotropic structure under shear

When designing up-to-date composite structure defects are allowable. In this case an important factor for design is in-service non-propagation of allowable defects. Thin surface defects of rectangular delamination type are examined in this paper. Defect structure is anisotropic and boundary conditions correspond to rigid support. Let us assume that tangential forces act in load-bearing composite panel plane. This investigation subject is thin surface rectangular defect. It is assumed that given shear forces act on the defect and its geometrically non-linear behavior is possible. For expert estimation of defect mode of deformation by Bubnov-Galerkin method analytical solution of non-linear problem is obtained. Expressions for rectangular panel membrane stress which appear in case of post-buckling behavior due to shear are explicitly given for mode of deformation estimation. In order to supplement practical significance of obtained analytical solution thin anisotropic panel design method based on post-buckling state with tangential forces is shown.