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In this article, a multilayered and higher-order-deformable finite element is developed for free vibration analysis of multilayer-deformable laminates such as laminated plates with constrained viscoelastic interlayers. The developed finite element (FE) is based both on the multilayer theory and on the higher-order theory, in which the cubic variations of the in-plane displacements and the quadratic of the out-of-plane displacements are assumed for each discrete layer. In the present multilayer FE, the displacement continuity constrains at the layer interfaces are enforced through the penalty function method. For numerically predicting modal loss factors as damping effectiveness of laminates, the modal strain energy method is also implemented into the present FE analysis. In addition to the FE development, well-devised experimental measurements are conducted to obtain dynamic properties of several actually fabricated laminated coupons and sandwich panels, which contain some viscoelastic layers for improving damping performance. Comparisons of the numerical results by the present and the conventional FEs with the experimental results obtained are made to investigate the accuracy and validity of both the present FE and the experiment itself for dynamic characterization of such special-purpose, multilayer-deformable laminates and sandwiches as are dealt with in this study. [ABSTRACT FROM AUTHOR]

The aim of this paper is to show an accurate method to predict thermal deformations of honeycomb sandwich panels having composite skins. First of all, some problems of the conventional method using the laminate theory are pointed out. In order to develop an effective predicting method, a model on detailed structure of a unit cell for sandwich panels is developed utilizing the 3D finite element method. A periodic boundary condition is introduced to the model to represent the repetitive structures of the sandwich panel. The effective elastic modulus of the cell foil is obtained from the result of an out-of-plane compressive test on the honeycomb core. The adhesives between skin and core is modeled by considering its shape and quantity. The difference between the CTE according to this model and the actually measured one is approximately 0.1 × 10[sup -6]/K. The paper further attempts to explain the anisotropic character of the sandwich panel. The result of this analysis suggests that the direction-dependency of the CTE is underestimated with the fact that the effective elastic modulus at a portion where a ribbon is bonded with another one is different from the effective elastic modulus at a portion where the ribbon is on its own. [ABSTRACT FROM AUTHOR]