Symmetric laminate buckling

The temperature-dependent Euler buckling load Pg(T) depended on the temperature-dependent bending stiffness EI(T), as demonstrated by Eq. (7.12). Owing to a symmetric laminate architecture, the neutral axis was always located at mid-depth, and therefore, the moment of inertia, I, was temperature-independent and the specimen stiffness could be determined as ... 

The buckling load will be determined for plates with various laminations specially orthotropic, symmetric angle-ply, antisymmetric cross-ply, and antisymmetric angle-ply. The results for the different lamination types will be compared to find the influence of bend-twist coupling and bending-extension coupling. As with the deflection problems in Section 5.3, different simply supported edge boundary conditions will be used in the several problems addressed for convenience of illustration. 

Normalized fundamental natural frequencies for the exampie un-symmetrical cross-piy laminated graphite-epoxy piates are shown in Figure 5-40. The vibration resuits are analogous to the buckling resuits in the same manner as explained for antisymmetric iaminates, nameiy, iesser differences for vibration frequencies because of the square-root factor. 

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