Effect of anisotropy on stresses in rotating discs

Stresses and deformations resulting from centrifugal forces in rotating specially orthotropic circular plates are determined. The classical laminated plate theory is employed in the analysis, and the results are presented in a manner which illustrates the effect of anisotropy. The plate is assumed to be rigidly fixed to a concentric rod allowing no deformation in its central region. The outer boundary is either free of any constraints or the plate is placed in a stiff casing which prevents radial deformation. A stiffness ratio, which is defined as the ratio of circumferential stiffness to radial stiffness, is used as the parameter to indicate the degree of anisotropy. Having a stiffness ratio greater than one eliminated the stress build-up on the boundaries. Higher stiffness ratios reduced the compressive stresses which began to occur near the outer boundary when the boundary was restrained from radial expansion, thus contributing to stability against local buckling. The results of Tsai-Wu failure analysis also showed that the choice of a stiffness ratio higher than one gives higher resistance against ply failure in tension.