Estimation of the Plain High-Cycle Fatigue Propagation Resistance in Steels

Chapetti, Mirco Daniel

doi:10.1590/s1516-14392002000200003

Cited by 2 publications

(4 citation statements)

References 14 publications

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“…According to the plot of Kitagawa and Takahashi and Chapetti, the material threshold for crack propagation is defined as

Δ K_{italicth} = Δ K_{th - s} + Δ K_{th - cl}

Δ K_{th - cl} = (Δ K_{italicthR} - Δ K_{th - s}) [1 - e^{- k (a - d)}]

where Δ K th is the material threshold of short fatigue crack, Δ K th − cl is the component of the stress intensity factor range corresponding to crack closure, as a function of crack length, Δ K thR is the threshold for long crack under the stress ratio R and k is the level of the crack closure.…”

Section: Methods Of Analysismentioning

confidence: 99%

“…51 A physically short crack threshold and propagation driving force model are proposed by Chapetti. [24][25][26][27][28] In his model, the physically short crack behaviour is obtained from the microstructure and the long crack propagation. However, the model did not include the effects of plasticity.…”

Section: The Threshold Value For Short Crack Propagationmentioning

confidence: 99%

“…Chapetti [24][25][26][27][28] proposed a physically short crack threshold and propagation driving force model. In his model, the physically short crack behaviour is obtained from the long crack propagation, just introducing the reduced threshold due to crack closure.…”

Section: N O M E N C L a T U R Ementioning

confidence: 99%

“…According to the plot of Kitagawa and Takahashi 50 and Chapetti, [24][25][26][27][28] the material threshold for crack propagation is defined as…”

Section: The Threshold Value For Short Crack Propagationmentioning

confidence: 99%

See 3 more Smart Citations

Prediction of short fatigue crack growth of Ti‐6Al‐4V

Wang

Cui

et al. 2014

Fatigue Fract Eng Mat Struct

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A B S T R A C T It is observed that the short fatigue cracks grow faster than long fatigue cracks at the same nominal driving force and even grow at stress intensity factor range below the threshold value for long cracks in titanium alloy materials. The anomalous behaviours of short cracks have a great influence on the accurate fatigue life prediction of submersible pressure hulls. Based on the unified fatigue life prediction method developed in the authors' group, a modified model for short crack propagation is proposed in this paper. The elastic-plastic behaviour of short cracks in the vicinity of crack tips is considered in the modified model. The model shows that the rate of crack propagation for very short cracks is determined by the range of cyclic stress rather than the range of the stress intensity factor controlling the long crack propagation and the threshold stress intensity factor range of short fatigue cracks is a function of crack length. The proposed model is used to calculate short crack propagation rate of different titanium alloys. The short crack propagation rates of Ti-6Al-4V and its corresponding fatigue lives are predicted under different stress ratios and different stress levels. The model is validated by comparing model prediction results with the experimental data.Keywords crack propagation threshold; fatigue crack propagation rate; short fatigue cracks; titanium alloy; unified fatigue life prediction method. N O M E N C L A T U R Ea = the crack length A = a material-sensitive and environmentally sensitive constant of dimensions in the crack growth rate model A 0 , A 1 , A 2 , A 3 = the coefficients defined to calculate the crack opening function f op d = THE intrinsic crack length da/dN = Fatigue crack growth rate f op = a crack opening function defined as the ratio K op /ΔK k = a material constant that reflects the rate of crack closure development with crack advance K cf = the fracture toughness of the material K max = the maximum stress intensity factor K min = the minimum stress intensity factor m = a constant representing the slope of the corresponding fatigue crack growth rate curve dimensions in the crack growth rate model n = the index indicating the unstable fracture in the crack growth rate model r e = an empirical material constant of the inherent flaw length of the order of 1μm R = the stress ratio defined by σ min /σ max Y = a geometrical factor to calculate the stress intensity factor α = a parameter used to calculate the 'virtual strength' of the material α ′ = the plane stress/strain constraint factor ΔK effth = the effective range of the stress intensity factor at the threshold level

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“…According to the plot of Kitagawa and Takahashi and Chapetti, the material threshold for crack propagation is defined as