MODEL AND METHOD FOR CALCULATING CYCLIC DAMAGE UNDER HIGH-FREQUENCY LOADING OF HOURGLASS-SHAPED SAMPLES

Previously obtained analytical formulas for natural frequencies and vibration modes of inhomogeneous hourglass-shaped rods are applied to obtain geometric and elastic characteristics of samples and to estimate the amplitudes of axial stresses obtained during experimental studies of fatigue strength of metal alloys under high-frequency cyclic loading. A numerical method based on a multi-regime fatigue failure model is proposed for calculating damage kinetics under high-frequency cyclic tension-compression loading of hourglass-shaped specimens at different stress ratios. The calculations based on the proposed model are compared with the results of experiments on hourglass-shaped titanium alloy samples. The proposed model and calculation method make it possible to construct fatigue curves with sufficient accuracy for various cyclic loading conditions and stress ratios. This problem requires knowing the base points of the bimodal fatigue curve for a fully reverse cycle.