Semnan University Press Journal of Modeling in Engineering 2008-4854 8 22 2010 10 23 NUMERICAL AND EXPERIMENTAL STUDY ON THE EFFECT OF OVERLOAD RATIO ON FATIGUE LIFE NUMERICAL AND EXPERIMENTAL STUDY ON THE EFFECT OF OVERLOAD RATIO ON FATIGUE LIFE 51 58 1567 10.22075/jme.2017.1567 FA Journal Article 2017 01 28 Fatigue life and crack growth retardation due to periodic tensile overloads which are superposed on constant amplitude cycles have been investigated. In the numerical analysis the Forman/Mettu equation with the generalized Willenborg model is used. Analyses and experiments are performed on C(T) specimens made of 7075 aluminium. In the experiments and analyses the periodicity of overloads was remained constant and the effect of overload ratio on the fatigue life has been researched. Results of the experiments and analyses reveal that the N/NCA versus OLR curve has a maximum which indicates that there are greater retardation effects in intermediate OLR values. Also the numerical and experimental results show that in occurrence ratio of 1/50 the overload ratio of 1.5 lead to the maximum interaction. Fatigue life and crack growth retardation due to periodic tensile overloads which are superposed on constant amplitude cycles have been investigated. In the numerical analysis the Forman/Mettu equation with the generalized Willenborg model is used. Analyses and experiments are performed on C(T) specimens made of 7075 aluminium. In the experiments and analyses the periodicity of overloads was remained constant and the effect of overload ratio on the fatigue life has been researched. Results of the experiments and analyses reveal that the N/NCA versus OLR curve has a maximum which indicates that there are greater retardation effects in intermediate OLR values. Also the numerical and experimental results show that in occurrence ratio of 1/50 the overload ratio of 1.5 lead to the maximum interaction. https://modelling.semnan.ac.ir/article_1567_3cf31ca348db33e05cac985e46fa8119.pdf