Stability Analysis of Composite-Plate Foundation Interaction by Mixed FEM

Abstract

The main objective of this research was to investigate the stability analysis of the composite laminated plate-Pasternak-type (two-parameter) foundation interaction and the influence of the second parameter on the critical buckling loads. Two-parameter foundation models are more accurate than the one-parameter (Winkler) foundation model. A functional for thin laminated composite plates was obtained with the proper dynamic and geometric boundary conditions using the Gateaux differential via potential operator concept. The functional was linearized by the incremental formulation, and the necessary steps of the stability analysis for the mixed finite-element method were given. As a special case, if the second parameter was neglected, the mechanical modeling of the foundation using the Pasternak formulation converged to the Winkler formulation. A four-noded quadrilateral, isoparametric, C-sup-0 class element with 4-by-9 degrees of freedom was generated. The independent variables per node were three translations, three membrane forces, and three moments. The element was verified by the numerical studies existing in the literature. It was observed that the influence of the second parameter on the critical buckling loads was noticeable, and the results were closely related to the foundation modeling.