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The Nonlinear Theory of the Snoek Relaxation Effect under the Strong and Homogeneous Bias Stress System

Ogurtani, Tarik Ömer
The nonlinear theory of energy dissipation associated with the mobile paraelastic octahedral interstitial atoms in inhomogeneous interaction fields is applied to the specific problem of the ordinary Snoek relaxation under the influence of the uniform static stress system (an external bias field). In the case of a uniaxial static bias stress system, an extremely accurate and simple analytical expression is deduced for the logarithmic decrement which indicates strong dependence on the magnitude, sign, and direction of the externally applied bias stress with respect to the direction of the excitation field in body centered cubic lattices. It is also demonstrated that by the internal friction measurements in single crystals, utilizing the large on‐line (parallel) and/or off‐line (orthogonal) static bias fields, the direct information about the symmetry, shape and strength of the elastic dipole tensor associated with the equilibrium‐point configurations (intrinsic) can be obtained.