Influence of mean stress and variable amplitude loading on the fatigue behaviour of a high-strength steel in VHCF regime

Sander, Manuela; Müller, Thomas; Lebahn, Jens

doi:10.1016/j.ijfatigue.2013.04.015

Cited by 64 publications

(58 citation statements)

References 34 publications

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“…For example, in the case of VHCF for a medium-carbon structural steel tested by rotary bending (52.5 Hz) in laboratory air with the stress ratio of R = À1, fatigue crack initiated from the subsurface or the interior of specimen with FiE pattern but without FGA morphology [24]. A similar case is the VHCF for a mediumcarbon structural steel tested by ultrasonic axial cycling (21 kHz) in laboratory air with the stress ratios of R = À1 and R = 0, for which cracks nucleated at non-metallic inclusions in the interior of specimen with FiE morphology but FGA was not visible on fracture surfaces [25]. Another interesting case [26] is that, for a high-carbon bearing steel with axial cycling (50 Hz) under the stress ratios of R = 0 and R = 0.5, fatigue cracks initiated from the interior of specimen with FiE pattern and FGA morphology at the failure cycles of 6.22 Â 10 7 at R = 0, whereas the initiation region was with FiE but without FGA morphology at the failure cycles of 2.57 Â 10 5 at R = 0.…”

Section: Introductionmentioning

confidence: 91%

The formation mechanism of characteristic region at crack initiation for very-high-cycle fatigue of high-strength steels

Hong

Liu

Lei

et al. 2016

International Journal of Fatigue

232

165

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a b s t r a c tFor high-strength steels, the crack initiation of very-high-cycle fatigue (VHCF) is commonly at the interior of material with fish-eye (FiE) morphology containing a fine-granular-area (FGA) surrounding an inclusion as crack origin, and FGA is regarded as the characteristic region of crack initiation. Here, we carefully examined the micro-morphology of FGA and FiE for two high-strength steels. The results revealed that the microscopic nature of FGA is a thin layer of nanograins. Then we proposed the formation mechanism of FGA: Numerous Cyclic Pressing (NCP) between originated crack surfaces, which causes grain refinement at originated crack wake and therefore the formation of FGA. The results of second set experiment showed that the cases with negative stress ratios exhibit the prevalence of nanograin layer in FGA region and the nanograin layer vanishes for the cases with positive stress ratios, which is a verification of the proposed NCP model.

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Section: Introductionmentioning

confidence: 91%

The formation mechanism of characteristic region at crack initiation for very-high-cycle fatigue of high-strength steels

Hong

Liu

Lei

et al. 2016

International Journal of Fatigue

232

165

View full text Add to dashboard Cite

show abstract

“…In the crack initiation and early growth stage of VHCF, the crack growth rate is much lower than 10 −10 m/cycle [13,[17][18][19][20]. This indicates that the crack growth in the FGA region occurs first for the most favorable path and does not always extend in all directions in each fatigue cycle.…”

Section: Model and Analysismentioning

confidence: 96%

“…It was shown that the stress intensity factor range at the front of the FGA was a constant and was close to the threshold value of the crack propagation K th . In crack initiation and early growth stage of VHCF, the crack growth rate is much lower than 10 −10 m/cycle [13,[17][18][19][20], and more than 90 % of fatigue life is consumed to form the FGA [21][22][23][24][25]. Therefore, it is essential to develop a model to predict the fatigue life in relation to FGA.…”

Section: Introductionmentioning

confidence: 99%

A two-parameter model to predict fatigue life of high-strength steels in a very high cycle fatigue regime

2015

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In this paper, ultrasonic (20 kHz) fatigue tests were performed on specimens of a high-strength steel in very high cycle fatigue (VHCF) regime. Experimental results showed that for most tested specimens failed in a VHCF regime, a fatigue crack originated from the interior of specimen with a fish-eye pattern, which contained a fine granular area (FGA) centered by an inclusion as the crack origin. Then, a two-parameter model is proposed to predict the fatigue life of high-strength steels with fish-eye mode failure in a VHCF regime, which takes into account the inclusion size and the FGA size. The model was verified by the data of present experiments and those in the literature. Furthermore, an analytic formula was obtained for estimating the equivalent crack growth rate within the FGA. The results also indicated that the stress intensity factor range at the front of the FGA varies within a small range, which is irrespective of stress amplitude and fatigue life.

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“…Firstly, a new procedure to rebuild the induction hardening induced residual stress was formulated onto a powered axle made of 34CrNiMo6 steel [16,17]. To derive the remaining life of sampled axles, a fatigue crack growth (FCG) model based on low cycle fatigue (LCF) response from open data was employed [9,18].…”

Section: Introductionmentioning

confidence: 99%

On the residual life assessment of high-speed railway axles due to induction hardening

Liu

et al. 2018

International Journal of Rail Transportation

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Surface hardening treatment can significantly increase the hardness of axle surface and introduce negative residual stress field into the axle. This work proposed an integrated stress rebuilding strategy of unit pressure and proportional integral approach to conduct the residual life prediction of an induction hardened axles and a load spectrum. A large crack aspect ratio a/c = 0.9 at the transition was used to predict the residual lifetime. It is well found that the hardened layer can provide a considerable fatigue resistance. Moreover, the critical stress region transfers to the inside of the axle or beneath the hardening layer rather than the free surface. Due to compressive residual stress, the evolved crack shape of hardened axles is completely different from original axles, showing a large aspect ratio. Totally, surface strengthened axles can acquire a prospective extended residual life. ARTICLE HISTORY

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Influence of mean stress and variable amplitude loading on the fatigue behaviour of a high-strength steel in VHCF regime

Cited by 64 publications

References 34 publications

The formation mechanism of characteristic region at crack initiation for very-high-cycle fatigue of high-strength steels

The formation mechanism of characteristic region at crack initiation for very-high-cycle fatigue of high-strength steels

A two-parameter model to predict fatigue life of high-strength steels in a very high cycle fatigue regime

On the residual life assessment of high-speed railway axles due to induction hardening

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