Issue 37

N.R. Gates et alii, Frattura ed Integrità Strutturale, 37 (2016) 160-165; DOI: 10.3221/IGF-ESIS.37.22 165 for other multiaxial loading conditions. It was found that by changing σ y to G Δ γ in the FS parameter, the correlation of high tensile mean stress data was improved while retaining all the same physical interpretations of the parameter and adding no new material constants. Additionally, a limited number of discriminating load path tests, performed using 2024- T3 aluminum alloy, suggest that the modified FS parameter may also be able to better account for some of the effects of axial and shear stress interaction on fatigue damage. Although the results of this study are encouraging, more experimental data and analysis are still needed, for different materials and loading conditions, to verify these findings. Figure 3 : Fatigue life correlations for 2024-T3 aluminum alloy based on (a) FS and (b) modified FS parameters with uniaxial strain-life properties and k = 1. A CKNOWLEDGEMENTS pecial thanks are given to the United States Naval Air Systems Command (NAVAIR) for financial support of this study and to Nam Phan for serving as a technical point of contact. REFERENCES [1] You, B.-R., Lee, S.-B., A critical review on multiaxial fatigue assessments of metals, Int. J. Fatigue 18 (1996) 235–244. [2] Socie, D.F., Marquis, G.B., Multiaxial Fatigue, Society of Automotive Engineers Inc., Warrendale, PA, (2000). [3] Fatemi, A., Socie, D.F., A critical plane approach to multiaxial fatigue damage including out-of-phase loading, Fatigue Fract. Eng. Mater. Struct. 11 (1988) 149–165. [4] Zhao, T., Jiang, Y., Fatigue of 7075-T651 aluminum alloy, Int. J. Fatigue 30 (2008) 834–849. [5] Meyer, N., Effects of Mean Stress and Stress Concentration on Fatigue Behavior of Ductile Iron, MSc Thesis, University of Toledo, Toledo, OH, (2014). [6] Shamsaei, N., Multiaxial Fatigue Deformation Including Non-proportional Hardening and Variable Amplitude Loading Effects, PhD Dissertation, University of Toledo, Toledo, OH, (2010). [7] Gates, N.R., Fatemi, A., Multiaxial variable amplitude fatigue life analysis including notch effects, Int. J. Fatigue (In Press 2016). DOI: 10.1016/j.ijfatigue.2015.12.011. [8] Gates, N.R., Fatemi, A., Friction and roughness induced closure effects on shear-mode crack growth and branching mechanisms, Int. J. Fatigue (In Press 2016). DOI: 10.1016/j.ijfatigue.2016.01.023. S (a) (b)