Fatigue strength of metals and composites under repeated high-cycle torsion

The limiting stresses are determined and constant fatigue life diagrams for high-cycle torsion with repeated stress cycle are plotted using the limiting-state models obtained based on the hypothesis of a unified constant-life diagram, which is invariant to the number of cycles to failure. The unified constant-life diagram is given by a transcendental power function whose exponent is an additional parameter characterizing the sensitivity of the material to the asymmetry of the stress cycle. The calculated results and experimental data for carbon and alloyed steels and composite materials are in good agreement