In the present work, fatigue crack growth behaviors of AA6061 are studied at different stress ratios, R = 0.1, 0.5 and 0.9. The fatigue crack growth rate and stress intensity factors at steady-state regime were determined by fatigue test on compact tension specimens. Fatigue tests were performed according to ASTM standards using Biss 25-kN, servo-hydraulic testing machine with graphic interface and auto-calibration. Lower fatigue crack growth rate as well as a higher fatigue crack growth threshold for stress ratio, R = 0.1, was observed and compared to R = 0.5 and 0.9. The dependency of crack growth on stress ratio is also modeled based on Walker approach, and Walker exponent was identified to model the dependency of fatigue crack growth rate of AA6061-T6 on stress ratios. The mathematical model developed shows 95% adj R square, which is acceptable.
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Moreira PMGP, de Jesus AMP, Ribeiro AS, de Castro PMST (2008) Fatigue crack growth in friction stir welds of 6082-T6 and 6061-T6 aluminium alloys: a comparison. Theoret Appl Fract Mech 50:81–91CrossRefGoogle Scholar
Rodopoulos Chris A, Alexis T (2007) Kermanidis: understanding the effect of block overloading on the fatigue behaviour of 2024-T351 aluminium alloy using the fatigue damage map. Int J Fatigue 29:276–288CrossRefGoogle Scholar
Jogia BF, Brahmankar PK, Nanda VS, Prasad RC (2008) Some studies on fatigue crack growth rate of aluminum alloy 6061. J Mater Process Technol 201:380–384CrossRefGoogle Scholar
Thomas WM (1986) The effect of single overloads upon fatigue cracks in 5083-H321 aluminium. Eng Fract Mech 23(6):1015–1029CrossRefGoogle Scholar
Borrego LP, Ferreira JM, Costa JM (2001) Fatigue crack growth and crack closure in an AlMgSi alloy. Fatigue Fract Eng Mater Struct 24:255–266CrossRefGoogle Scholar
Noroozi AH, Glinka G, Lambert S (2005) A two parameter driving force for fatigue crack growth analysis. Int J Fatigue 27:1277–1296CrossRefzbMATHGoogle Scholar
Bergner F, Zouhar G, Tempus G (2001) The material-dependent variability of fatigue crack growth rates of aluminium alloys in the Paris regime. Int J Fatigue 23:383–394CrossRefGoogle Scholar
Mann T (2007) The influence of mean stress on fatigue crack propagation in aluminium alloys. Int J Fatigue 29:1393–1401CrossRefGoogle Scholar
Kujawski D (2001) A new (ΔK + Kmax)0.5 driving force parameter for crack growth in aluminium alloys. Int J Fatigue 23:733–740CrossRefGoogle Scholar
Kujawski D, Stoychev S (2003) Parametric study on the variability of opening load determination. Int J Fatigue 25:1181–1187CrossRefGoogle Scholar
Schijve J (1981) Some formulas for the crack opening stress level. Eng Fract Mech 14(3):461–466CrossRefGoogle Scholar