Deformation resistance and limiting state of structural materials in multiaxial low-cycle deformation

The results are presented of investigations into the relationships governing low-cycle fatigue of VT14 alloy and 14Kh17N2 steel at T=290 K under the conditions of proportional and nonproportional rigid low-cycle loading. Symmetric and pulsed (nonzero) deformation cycles were examined. The limits of applicability of the determining equation in the form of a generalized diagram of low-cycle loading for the case of piecewise-broken flat trajectories were determined. The results show that strain asymmetry has a strong effect on the endurance (in the stage of macrocrack formation) because of the special features of the deformation resistance of structural materials in the presence of a mean strain and the effect of the properties of cyclic hardening and softening.Translated from Problemy Prochnosti, No. 10, pp. 11–16, October, 1990.