Calculation of long-term strength on the base of the Hoff viscous failure model

A problem on the prediction of a long-term strength of materials under stationary static loading is considered. Main approaches used under solution of such class of problems is briefly characterized. Applicability of the Henki-Hoff concept based on the unlimited viscous flow of the material is analyzed on the example of metallic materials. Modifications of the model regarding initial elastic deformation and deformation of the unsteady creep, deformation and stress limitations are considered. It is shown that the Hoff model may be used for prediction of a long-term strength of high-plastic (Eb≥20%) materials and for calculation of time before the failure of the members.