Non-Monotonic Switching between Symmetric and Asymmetric Modes in Thermal Buckling of an Annular Plate on a Partial Foundation

A precise understanding of the thermal buckling of annular plates on partial foundations is crucial for ensuring the safety and reliability of many critical engineering systems. This paper investigates this phenomenon on a partial Pasternak foundation, establishing the governing equations and the boundary conditions based on the first-order shear deformation theory and the von Kármán geometric nonlinearity, and solving them via the differential quadrature method. A key finding, distinguishing this work from previous studies, is the non-monotonic switching between symmetric and asymmetric fundamental buckling modes induced by the partial foundation. This mode switching is attributed to the evolution of the radial buckling shape. Specifically, high Winkler Spring stiffness can alter the radial buckling shape, impacting symmetric modes more than asymmetric modes. Crucially, the potential to induce a reversion to a symmetric mode by the Winkler Spring exists only under a partial foundation. The influence of the shear layer is also related to its coverage. In contrast to the monotonic effect of a complete shear layer, the influence of a partial shear layer is mode-dependent. For symmetric modes, a partial shear layer can lead to a lower critical buckling temperature rise, while for asymmetric modes, the trend is a consistent increase. This mode-dependent behavior, also originating from the alteration of the radial buckling shape, further contributes to the overall symmetry switching phenomenon.