Integrated design and analysis of sinusoidally and circularly corrugated-core sandwich plates using multi-patch isogeometric Reissner–Mindlin shell analysis

Corrugated-core sandwich plates have attracted significant attention in engineering applications due to their exceptional lightweight properties, high stiffness-to-weight ratios and excellent impact resistance. This paper presents a novel multi-patch isogeometric analysis model for the static bending and free vibration analysis of sinusoidally and circularly corrugated-core sandwich plates, which consist of face panels, a core shell, and stiffeners. All structural components are modeled through their mid-surface representations using the Reissner–Mindlin shell theory, which accounts for transverse shear deformation effects and requires only C⁰ continuity of shape functions across element interfaces. NURBS-based discretizations are employed to represent both the mid-surfaces and displacement fields. The discretized formulations including the stiffness matrix, mass matrix and external force vector, are derived in detail. To address the non-conforming discretization at the interfaces between the face panels, core shell and stiffeners, a penalty-based weak coupling method is introduced to ensure displacement continuity. Several numerical examples are implemented to validate the developed formulations and the convergence behavior is carefully assessed. Furthermore, the impacts of shell thickness, the number of unit cells, and plate height on the deflection and dimensionless frequency parameters of the sandwich plates are thoroughly investigated. The results demonstrate that the proposed isogeometric framework offers an effective and robust tool for integrated design and analysis of sinusoidally and circularly corrugated-core sandwich plates.