Laminated Partially-Composite Plate Theory (LPCPT)-An extension of the classical laminated plate theory for flexible n-layer plates with partial interlayer interaction

Journal article, 2026

This paper introduces the Laminated Partial-Composite Plate Theory (LPCPT), as an extension of the classical laminated plate theory (CLPT), incorporating the effects of partial-interaction imperfection at the constituting layers' interfaces. The interlayer interaction effects are modelled through out-of-plane shear stresses based on a shear spring model in terms of the relative displacements/slips at the interfaces. The proposed LPCPT extends a recently developed model for multilayer composite beam/column elements with interlayer partial-interaction imperfection. The model's governing equations, as well as the extended classical boundary conditions, are formulated. Analytical solution schemes are introduced for free vibrations and buckling of partial-composite plates. The analytical solutions can flexibly capture any number of constituent layers. The validity and high accuracy of the established approach are demonstrated via comparative numerical results based on 3-D finite element analysis (FEA). It is shown how the buckling loads and natural vibration frequencies degrade from those predicted based on CLPT with perfect-bonding ideal assumptions, considering different levels of interlayer interaction. For a special case where the interlayer interaction modulus is set to the equivalent layers' transverse shear modulus, the results of the present model are shown to match those of thick integrated plates based on higher-order shear deformation theory (HSDT).