A method was proposed which was aimed at modeling the size-effect in the long-term strength of rods subjected to uniaxial tension. The method was based upon the analysis of the diffusion of media in the rod material. Approximate solutions to the diffusion equation were obtained in axisymmetrical form for 2 types of boundary condition based upon the introduction of the diffusion front. Analysis of the data for 2 series of tests showed that the proposed method correctly described the observed size-effect. The approximate nature of the diffusion equation was responsible for an error, in the predicted times-to-fracture, which was equal to an average of 5%.

Evaluation of Long-Term Strength on the Basis of Approximate Solution of the Diffusion Equation. A.M.Lokoshchenko, D.O.Platonov: Materials Science, 2003, 39[1], 8-16