Thermal buckling of uniformly heated unidirectional and symmetric cross-ply laminated fiber-reinforced composite uniaxial in-plane restrained simply supported rectangular plates

Geometrically perfect plates that are restrained from in-plane expansion when slowly and uniformly heated generally develop compressive stresses and then buckle at a specific temperature. The equivalent mechanical loading concept is used to straightforwardly develop solutions to several fundamental thermal buckling problems involving simple laminated plate configurations and the most simple heating environment, namely uniform heating throughout the plate volume. The analysis is restricted to linear elastic stress-strain behavior and constant orthotropic lamina material properties at a specific temperature. Results are obtained for unidirectional and symmetric cross-ply laminated fiber-reinforced composite rectangular plates that are uniaxially restrained in their plane on two of the four edges, but have no edge rotational restraint on any edge. Those boundary conditions constitute two of the four possible types of simply supported edges that differ only in their in-plane conditions. The results are presented in the form of buckling temperature change from the stress-free temperature (at which no stress is generated against the restraint) versus plate aspect ratio curves festooned for different buckling mode shapes for all laminates. Anomalous examples include unidirectionally laminated plates that actually buckle upon cooling instead of heating and cross-ply laminated plates that do not buckle irrespective of whether they are heated or cooled. Those examples are of interest because of their intriguing possible design applications.