Sensitivity Analysis of Continuum Damage Parameters on Error and Scatter-band for Predicted Low-cycle Fatigue Lifetime of AZ61A Magnesium Alloy

In the present article, the sensitivity analysis of continuum damage parameters was presented on the relative error and the scatter-band for the predicted low-cycle fatigue lifetime of the AZ61A magnesium alloy. For such an objective, experimental data of low-cycle fatigue testing were utilized under torsional and tensile-compressive loadings. Then, the continuum damage mechanics method was implemented to experiments, in order to calibrate continuum damage parameters. The objective was maximum and averaged relative errors between predicted and experimental fatigue lifetimes and also the scatter-band for 100% and 75% covering of all data. The regression analysis was done by the Minitab software to obtained optimized continuum damage parameters, in order to have lower errors and narrower scatter-bands. Obtained results indicated that the superior value for the maximum relative error was less than 90% for both loading types. However, the best value for the averaged relative error was 37% and 38% for torsional and tensile-compressive loadings, respectively. The narrowest scatter-band between experimental and calculated fatigue lifetimes was about ±2.0 for 75% of torsional and tensile-compressive data, which implied an accurate prediction for the low-cycle fatigue lifetime of the AZ61A magnesium alloy by the continuum damage mechanics approach.