Postbuckling behavior of 3D braided rectangular plates subjected to uniaxial compression and transverse loads in thermal environments

Postbuckling behavior of the 3D braided rectangular plates subjected to uniaxial compression combined with transverse loads in thermal environments is presented. Based on a micro-macro-mechanical model, a 3D braided composite may be treated as a cell system and the geometry of each cell is deeply dependent on its position in the cross-section of the plate. The material properties of the epoxy are expressed as a linear function of temperature. Uniform, linear and nonlinear temperature distributions through the thickness are involved. The lateral pressure (three types of transverse loads, i.e. transverse uniform load; transverse patch load over a central area; and transverse sinusoidal load) is first converted into an initial deflection and the initial geometric imperfection of the plate is taken into account. The governing equations are based on Reddy’s higher-order shear deformation plate theory with a von Karman-type of kinematic nonlinearity. Two cases of the in-plane boundary conditions are also taken into account. A perturbation technique is employed to determine buckling loads and postbuckling equilibrium paths of simply supported 3D braided rectangular plates. The results reveal that the temperature rise, geometric parameter, fiber volume fraction, braiding angle, the character of the in-plane boundary conditions and different types of initial transverse loads have a significant effect on the buckling and postbuckling behavior of the braided composite plates.