Correlation of Uniaxial Cyclic Torsion and Tension-Compression for Low-Cycle Fatigue

We analyze the comparison of the fatigue characteristics and, in particular, the coefficients of tensioncompression and cyclic torsion based on the data of available tests performed under low-cycle fatigue in various materials. The correlation of torsion and tension-compression fatigue strength coefficients does not depend on the relative slope of the fatigue diagrams used to describe plastic strains. On the basis of the performed analyses, we conclude that the ratio of the fatigue strength coefficients in tensioncompression varies, in most materials, within the range from 0.5 to $$ \frac{1}{1+\nu } $$ . At the same time, the correlation of the strain-based fatigue coefficients in torsion and in tension-compression strongly depends on the relative slope of the plastic strain-based curves of fatigue life.