Thermoelastic formulation of stiffened, unsymmetric composite panels for finite element analysis of high speed aircraft

An emerging technology need for capturing 3-D panel thermoelastic response with 2-D planar finite element models (FEMs) is aided with an equivalent plate stiffness and thermal coefficient formulation. The formulation is general and applies to all material types and stiffened and sandwich panel concepts. Included with the formulation is the ability to provide membrane-bending coupling of unsymmetric sections and calculation of all thermal expansion and bending responses from in-plane and through-the-thickness temperature gradients. Thermal residual strains for both the laminates and plies are included. The general formulation is defined and then applied to a hat- shaped, corrugated stiffened, metal matrix, fiber-reinforced composite panel. Additional formulations are presented where required to include all of the hat''s unique characteristics caused by the cell shear flow in the closed section such as the in-plane shear and bending-twisting response. Each formulation is validated independently with 3-D FEA.