Model for Describing Fatigue Crack Growth Rate Considering Changes in the Threshold SIF

摘要

This paper considers an approach to the description of the fatigue crack growth invariant to the cycle asymmetry. For this purpose, the notion of a "current value of the threshold stress intensity factor" is introduced and a method for its determination is presented. Experimental data obtained on the basis of the approach proposed for four materials are given and a tendency to a close grouping of the data by the crack growth rate at different cycle stress ratios within one band is shown. It is assumed that the approach proposed approximates the part of the stress intensity factor to be considered to its effective value related to the crack growth rate.