Methodical Approach to the Analysis of Experimental Data Associated with the Fatigue Cracks Propagation Under Overload Conditions

The paper presents an analysis how overloads affect of fatigue cracks propagation rate where the analysis is carried out with use of the retardation model. The completed analysis covered the results of experimental examination of RCT-type samples made of the WT3-1 titanium alloy and was intended to determine interrelationships between individual parameters of the applied model. Comparison between theoretical calculations and experimental data was carried out for two options: with the analysis of samples for the entire range of lifetime until the sample was destroyed, and with a separate analysis of data for time intervals between the overload moments, whereby the values of C, m and n coefficients were determined each time for the retardation model. Finally, the dependence of coefficient values on the stress intensity factor during overload cycles is developed.