Thermoelastic geometrically nonlinear analysis and optimization of variable stiffness composite plates in presence of buckling

The thermal environment enhances the complexity of buckling failure of variable stiffness composite plates. Influences of the high temperature and large deflection should be well considered in both the buckling analysis and optimization design. However, the thermoelastic geometrically nonlinear analysis is computationally expensive, particularly inapplicable for the optimum of curvilinear fiber trajectories with more design variables. In this work, a novel reduced-order method based on the reformulated Koiter perturbation theory is developed for thermoelastic geometrically nonlinear analysis of variable stiffness composite plates. A reduced-order model is constructed for the variable-angle tow (VAT) placed composite laminates considering an initial temperature field. The initial temperature field is transformed to be an independent degree of freedom of the variable stiffness reduced system. The thermoelastic geometrically nonlinear response is obtained at little computational cost by solving the small-scaled reduced-order model, and then used as inputs in the VAT lamination optimization. The buckling resistance and postbuckling load-carrying capability of variable stiffness plates are fully exploited.