Multiaxial high cycle fatigue threshold with small defects and cracks

Yanase, K.; Endo, Mitsuru

doi:10.1016/j.engfracmech.2014.03.017

Cited by 38 publications

(37 citation statements)

References 29 publications

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“…It is seen from this figure that for the same value of

\sqrt{area}

, torsional fatigue limit of specimens with a 0° scratch is higher than the line corresponding to Equation and the experimental fatigue limit for circumferential notches under uniaxial loading . The value of τ w / σ w is approximately 1.2 to 1.3 that is much higher than the reported value of 0.73 to 0.94 for round shape, small defects . This is a unique characteristic of fatigue behavior of a specimen with a 0° scratch subjected to cyclic torsion.…”

Section: Resultsmentioning

confidence: 57%

“…Pure torsion fatigue is in essence biaxial fatigue of tension and compression so that the compressive stress ( σ 2 in Figure ) sometimes acts to decrease the fatigue limit, compared to that of the uniaxial fatigue . However, it is considered that in the case of the present material, SWOSC‐V, the effect of compressive stress was rather negligible presumably because of its high strength, and the torsional fatigue limit was the same as the uniaxial fatigue limit.…”

Section: Resultsmentioning

confidence: 84%

“…32 The value of τ w /σ w is approximately 1.2 to 1.3 that is much higher than the reported value of 0.73 to 0.94 for round shape, small defects. [16][17][18][19][20][21][22][23][24]42 This is a unique characteristic of fatigue behavior of a specimen with a 0°scratch subjected to cyclic torsion. Figure 12 shows the S-N data of specimens with 45°s cratches, and torsional fatigue limit decreased significantly in the presence of scratch.…”

Section: Effect Of 0°scratches On Torsional Fatigue Strengthmentioning

confidence: 99%

“…On the other hand, Endo and Murakami discussed this problem from the fracture mechanics point of view with consideration of the phenomenological fact that the fatigue limit of steel specimens with a small defect is not a critical condition for crack initiation but a threshold condition for the propagation of a crack emanating from the defect. Subsequently, Endo et al and Yanase et al showed that using the

\sqrt{area}

parameter model and a newly proposed multiaxial criterion, the fatigue limit for ferrous and nonferrous materials containing small defects under combined axial and torsional fatigue loadings was reasonably predicted. Beretta and Murakami re‐evaluated the experimental results in view of the threshold condition based on the results of 3D stress intensity factor (SIF) calculation for a crack emanating from drilled holes or semispherical pits.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Fatigue strength of spring steel with small scratches

Nishimura

Yanase

Ikeda

et al. 2018

Fatigue Fract Eng Mat Struct

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In compression coil springs subjected to cyclic load, fatigue cracks can sometimes initiate and propagate from scratch‐like small defects produced during the manufacturing process and degrade the fatigue strength. In this study, torsional and rotating bending fatigue tests were conducted to examine the fatigue behavior of a high‐strength spring steel (JIS G 3561, SWOSC‐V) in the presence of small scratches. The sensitivity of the HCF and VHCF strength to small scratches was evaluated based on the area parameter model.

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“…It is seen from this figure that for the same value of

\sqrt{area}

Section: Resultsmentioning

confidence: 57%

Section: Resultsmentioning

confidence: 84%

Section: Effect Of 0°scratches On Torsional Fatigue Strengthmentioning

confidence: 99%

\sqrt{area}

Section: Introductionmentioning

confidence: 99%

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Fatigue strength of spring steel with small scratches

Nishimura

Yanase

Ikeda

et al. 2018

Fatigue Fract Eng Mat Struct

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View full text Add to dashboard Cite

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“…It has been reported that for various metallic materials, the fatigue limit as a crack‐growth threshold can accurately be predicted by the

\sqrt{area}

parameter model . This model states that Δ Κ th at a stress ratio of −1 depends on the size of the initial crack or defect and the hardness of the material, expressed by the following equation:

normalΔ Κ_{th} = 3.3 \times 10^{- 3} ((), italicHV + 120) {(\sqrt{area})}^{1 / 3} .

The unit is MPa

\sqrt{m}

for Δ Κ th .…”

Section: Resultsmentioning

confidence: 99%

Effect of defects on the fatigue limit of Ni‐based superalloy 718 with different grain sizes

Kevinsanny

Okazaki

Takakuwa

et al. 2019

Fatigue Fract Eng Mat Struct

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Tension‐compression fatigue tests were performed on two types of Ni‐based superalloy 718 with different microstructures in which small artificial defects of various sizes and shapes were introduced. The susceptibility of the fatigue strength to the defects varied significantly with the microstructure morphology, ie, a smaller grain size made the alloy more susceptible to defects. The fatigue limit as a small‐crack threshold was successfully predicted using the area parameter model. The evaluation of the fatigue limit was classified into the following three stages depending on the defect size: (a) harmless defect regime, (b) small‐crack regime, and (c) large‐crack regime. Such a classification enabled comprehensive evaluation of the fatigue limit in a wide range of defect size, considering (a) defect size over a range of small crack to large crack and (b) characteristics of matrix represented by grain size and hardness.

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