An analytic homogenisation model for shear–torsion coupling problems of double corrugated core sandwich plates

The homogenisation of shear–torsion behaviours for orthotropic sandwich plates such as corrugated cardboards is a difficult task, even numerically. We decompose the plate torsion into two beam torsions in order to analytically calculate its torsion rigidity. A simple but fairly accurate model based on Bredt theory is proposed for the torsion rigidity of double corrugated core plates. The in-plane shear rigidity is also analytically determined using beam theory. For non-symmetric plate sections, an analytical formulation is developed for the shear–torsion coupling problem. Very good agreement is obtained between the three-dimensional shell simulations and our fast H-model for a non-linear buckling problem coupling the membrane-shear-bending-torsion effects.