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The dynamic behavior of soft-core sandwich plates is investigated. A high-order finite element concept that has been developed for the dynamic analysis of multi-layered plate structures with stiff and compliant layers is applied to the soft-core sandwich plate. The application to sandwich plates aims to validate the general model through comparison with experimental and analytical benchmarks and to throw light on the unique structural response of the sandwich plate. The model introduces the core’s three-dimensional stress and deformation fields using a high-order kinematic assumption that is based on the closed-form solution of the static governing equations of the core. The first-order shear deformation laminated plate theory is used for the face sheets. The combination of the high-order theory with the finite element concept aims to extend the application of the theory to more general layouts, to reduce the computation effort needed for a three-dimensional analysis, and to address some of the obstacles due to differences in length scales and elastic properties. The validity and the capabilities of the formulation are examined through comparison with experimental and analytical results taken from the literature. In addition, the static, free vibration, and dynamic behaviors of an ‘L’ shaped sandwich plate subjected to localized loads and boundary conditions are numerically studied. The formulation, the comparison with experimental and analytical benchmarks, and the numerical study highlight the three-dimensional effects and reveal unique aspects of the dynamic response of soft-core sandwich plates.

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The role of the adhesive layers in active panels with surface-mounted (bonded) piezoelectric layers is studied. The investigation focuses on the strain transfer mechanism between the active layers and the host structure, the stress concentrations involved, and the influence of the geometrical and mechanical properties of the adhesive layers on the static response of the panel. The analysis is based on the High-Order approach and uses 2D elasticity to model the adhesive layers. The mathematical formulation is derived using variational principles, compatibility requirements, and the piezoelectric constitutive equations. Confirmation of the analytical model is achieved through an experimental study that reveals good agreement between the theoretical predictions and the behavior of the active structure. Numerical results are presented for a typical piezoelectric active panel and compared to detailed 2D finite element analysis. The results reveal the high-order effects and the stress concentrations in the transition zone near the edge of the panel and indicate that a careful selection of the adhesive's properties can improve the behavior of the structure and reduce the severity of the stress concentrations involved. The paper concludes with a summary and recommendations for the analysis, design, and use of smart structures with bonded actuators.

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