Criteria for determining the long-term strength under conditions of complex loading

Abstract

It has been pointed out that the problem of determining the long-term strength under complex conditions of loading consists in the simultaneous choice of an equivalent stress σ_e and the nature of the dependency of the failure time t^* on the value of σ_e. This is best described by a series of experimental data taken at constant temperature. The problem can be solved by introducing a parameter D which characterizes the total discrepancy between the experimental and theoretical values of t^*, and through the use of a technique for determining the material constants which will lead to a minimum value of D. As an example of this approach, a quantitative treatment of the experimental data given by I.I. Trunin and A. A. Lebedev is presented.