Stress and strain estimates for Newtonian and non-Newtonian materials in a rotational shear zone

Stress and shear strain rate in a rotational shear zone between two concentric circular boundaries are estimated for both Newtonian and non-Newtonian materials. Tangential shear stress in the shear zone τ_rθ is proportional to 1/r², where r is distance from the centre of rotation. The principal stresses σ₁ and σ₃ at a point are oriented at 45° to the radius through the point from the centre of rotation. The shear strain rate over(γ, ̇) is proportional to 1/r²ⁿ, where n is the stress exponent in the constitutive equation. The distribution of strain ellipses systematically varies from place to place as a function of the total angle of rotation of the circular boundaries and of n. Deformation appears prominently concentrated in a narrow zone close to the interior boundary when n becomes large.