Thermodynamic nature of exponential empirical time dependences of strength characteristics and the failure of materials. Report 1. Creep and long-term strength

It is shown that the correlation between two parameters describing the power law of creep or the long-term-strength curve, which can be demonstrated on the basis of numerous experimental data, is governed by the thermodynamics of the processes of steady-state creep or creep-induced failure. Analytical expressions describing this correlation are obtained, and values of the parameters entering into this relationship are explained on the assumption of the logarithmic character of the dependence of the activation energy of the process on deforming stress. An independent method of evaluating the cohesive energy of the material from results of creep tests is proposed. A simple formula is presented for the a priori estimation of the slope of the long-term strength curve from the material's melting point.The paper is written as an outgrowth of a study performed by the authors, which was published in the journal Problemy Prochnosti, No. 6, 3–9 (194).Translated from Problemy Prochnosti, No. 2, pp. 5–24, February, 1996.