Evaluation of equivalent (by residual life) periods of thermal soaking during complex fatigue tests of samples of structural components

Abstract

For the purpose of the substantiation of the parameters of forced fatigue tests, equivalent (by residual life) periods of thermal soaking during complex fatigue tests of smooth samples were determined by the calculation method. The variation of the lifetimes of samples with a hole and samples of riveting joints of D16AT and AK4-1AT1 aluminum alloys was experimentally investigated as a function of the previous stress history. The effect of aging processes on the fatigue strength of the samples that occur during soakings with different durations under natural conditions during the action of heightened temperature was evaluated. During the selection of the parameters of forced fatigue tests, it was shown to be necessary to take into account the different nature of the variation of the mechanical characteristics of structural components, which depended on the type of the structural component, the alloy, the soaking temperature, and modes of the fatigue tests. The results can be used during the design of experiments for the evaluation of effects of various factors on the fatigue life of structural components and during the forecasting of their operational life.