Improved High-Cycle Fatigue (HCF) Life Prediction

Gallagher, John P.; Stone, R. H. Van; deLaneuville, Robert E.; Gravett, Phillip W.; Bellows, Richard S.

doi:10.21236/ada408467

Cited by 40 publications

(27 citation statements)

References 10 publications

(21 reference statements)

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“…For the duplex Ti-6Al-4V microstructure, the material parameters that have been shown to correlate the data are m = 0.45, A = 0.75, B = 0.5, C = 0.75, D = 0.5 [18,39]. The P MSSR is essentially a generalization of the Findley critical plane model [42] that was found to correlate Ti-6Al-4V multiaxial plain fatigue data well [1,2,36],…”

Section: Predicting Fretting Crack Formationmentioning

confidence: 94%

“…Since shear cracking is promoted in the crack nucleation of Ti-6Al-4V, shear-based critical plane parameters, particularly ones that include a normal stress parameter to account for normal mean stress effects, tend to work the best in predicting the location and orientation of the crack as well as correlating cycles to failure based on smooth specimen data [1,2,18,[36][37][38][39]. The two parameters that have exhibited the best success in correlating lives of Ti-6Al-4V include the FSK (FatemiSocie-Kurath) parameter [40,41], Key Engineering Materials Vols.…”

Section: Predicting Fretting Crack Formationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…% secondary lamellar α+β domains about 10 to 15 µm in size composed of alternating lathes of α and bcc-structured β. This was the baseline microstructure used for several projects carried out under the Air Force High Cycle Fatigue (HCF) program from 1995 to 2005 [1,2]. Unless noted otherwise, the majority of the data reported in this review was generated on this or similar microstructure.…”

Section: Introductionmentioning

confidence: 99%

“…Unless noted otherwise, the majority of the data reported in this review was generated on this or similar microstructure. The microstructure has an initial random texture with yield strength 930 MPa, ultimate tensile strength 978 MPa, and cyclic yield strength of 797 MPa [1].The fretting fatigue process can be divided into two parts. The first is the formation of fretting cracks and the second is the growth of fretting fatigue cracks.…”

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confidence: 99%

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The Fretting Fatigue Behavior of Ti-6Al-4V

Neu

2008

KEM

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Abstract. This paper reviews the understanding of fretting fatigue with an emphasis on the behavior of Ti-6Al-4V. Advances in life prediction and assessment approaches are highlighted. The role of microstructure on fretting fatigue and its use to detect fretting fatigue damage can now be considered in assessment strategies. Various palliatives are used to enhance the fretting fatigue resistance. These include treatments to introduce compressive residual stress and surface coatings that reduce friction and/or protect the underlying structural material. IntroductionThis paper reviews the tremendous progress over the past decade to understand and predict the fretting fatigue behavior of Ti-6Al-4V, a common alloy used in applications requiring high specific strength. Fretting fatigue is of particular concern for dovetail attachments between the blades and disks in compressors of aerospace gas turbines, spline couplings of shafts, and mechanical joints in orthopedic implants. In the past decade there has been considerable focus on the fretting fatigue behavior of the duplex microstructure consisting of 60 vol. % equiaxed primary α (hcp structure) and 40 vol. % secondary lamellar α+β domains about 10 to 15 µm in size composed of alternating lathes of α and bcc-structured β. This was the baseline microstructure used for several projects carried out under the Air Force High Cycle Fatigue (HCF) program from 1995 to 2005 [1,2]. Unless noted otherwise, the majority of the data reported in this review was generated on this or similar microstructure. The microstructure has an initial random texture with yield strength 930 MPa, ultimate tensile strength 978 MPa, and cyclic yield strength of 797 MPa [1].The fretting fatigue process can be divided into two parts. The first is the formation of fretting cracks and the second is the growth of fretting fatigue cracks. The drivers for each of these processes are different. Both processes must occur to realize a catastrophic fretting fatigue failure. If fretting cracks do not form, fretting fatigue will not occur. But even if fretting cracks form, a catastrophic fretting fatigue failure will not occur if these cracks do not grow outside of the fretting fatigue process volume (FFPV) associated with the formation of the crack. Hence, the fretting fatigue limit is associated with the threshold limit for propagating the fretting cracks. In most fretting fatigue experiments and in applications, the drivers for fretting crack formation and crack growth outside of the FFPV cannot be easily separated, so there is an apparent coupling between the two. However, experiments involving the independent control of the drivers for fretting crack formation and crack growth (e.g., [3,4]) suggest that these two processes can be separated for the purposes of material response and prediction analyses. This is extremely helpful in understanding how different palliatives mitigate the fretting drivers. Some palliatives are aimed at fretting crack formation while others at reducing the fretting fatigue crack...

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