Decay rates in a bimaterial circular cylinder

Decay rates in a bimaterial circular cylinder under axisymmetric torsion loading are considered via an eigen-expansion near the end of the cylinder. The decay rates depend on the shear modulus ratio of the materials and the radius ratio of inner and outer cylinders. Following the derivation of the traditional Saint-Venant end effect of an isotropic bimaterial cylinder, cases of anisotropic material (transversely isotropic material) and non-traditional Saint-Venant end effect (displacement prescribed on the side surface) are considered. This study sheds some light on the decay studies for other geometric configurations and the deformation modes of composite structures.