LOW-CYCLE FATIGUE OF METALS-LITERATURE REVIEW

An evaluation of the data on low-cycle fatigue of metals based on type of test, cyclic rate, stress concentration, crack propagation, material property change and method of analysis indicates that (a) there is presently no general analysis applicable to all low-cycle fatigue test con- ditions; (b) the shape of the load-time curve is an important factor in analyzing low-cycle fatigue tests; (c) the extent of the time effect on low-cycle fatigue behavior, particularly with respect to creep and crack propagation, still remains to be explored; (d) the use of strain rather than stress is more desirable in low-cycle fatigue studies of coupon-type specimens because of the plastic deformation that takes place during such tests; and (e) the fatigue hypotheses based on strain, although developed from limited data, exhibit good agreement with the test results and show promise of providing a good in- dication of low-cycle fatigue behavior for selected loading conditions.