In order to develop a computation method for the corrugated core panel bending issue and solve the bending deflection and stress of such panels, an equivalent stiffness method is proposed.

First, the middle cores of these sandwich panels are taken as equivalent to orthotropic elastic materials, then the equivalent elastic modulus of the cores are solved by Castigliano's theorem and the integral stiffnesses of the sandwich panels are calculated by laminated plate theory. According to the solved integral stiffness constants, the distribution of bending deflection is achieved by solving the orthotropic plate bending equilibrium equations, and stress distribution is derived by adopting Hooke's law.

It is validated that the stiffness error evaluated by this proposed method is -6.98% compared with the method in literature(Ref.[7]), the maximum error of deflection is -2.01% and stress is 3.63%, which correspond with the FEM results.

This proposed method for calculating integral stiffness through layered accumulation not only avoids the complicated derivation of applying the method of Ref.[7] completely, but also satisfies calculation precision when computing the bending issue.