Isotropic softening model for high-cycle fatigue

As known the high cycle loading of structural elements above the fatigue limit results in catastrophic propagation of macroscopic fatigue crack(s). Therefore it is in demand to find a method, which would allow for early prediction of the fatigue life-time of particular structural element.

The series of force-driven tests carried on 30CrNiMo8 steel have shown that, although the stresses by high-cycle fatigue do not reach the tensile stress, the material strength (measured indirectly from the strain-stress loop) decreases from the begin of the test, hence the damage nucleates and propagates from the very begin of the loading history.

In this study we propose a thermodynamically consistent, strain driven constitutive model for isotropic damage accumulation by high-cycle fatigue of a homogeneous isotropic material, which should be capable to account for the above-mentioned experimental results. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)