Effects of an Artificial Small Defect on Torsional Fatigue Strength of Steels

Endo, Mitsuru; Murakami, Yukitaka

doi:10.1115/1.3225951

Cited by 57 publications

(47 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The ratio  shows indeed an increase with the defect size. This is coherent with the trends observed in the literature by Endo et al [18] and Billaudeau et al [19] on other steels and represented in Fig. 6.…”

Section: Results and Discussion Of The Fatigue Testssupporting

confidence: 93%

Competition between microstructure and defect in multiaxial high cycle fatigue

Morel¹,

Guerchais²,

Saintier³

2015

Frattura Ed Integrità Strutturale

View full text Add to dashboard Cite

ABSTRACT. This study aims at providing a better understanding of the effects of both microstructure and defect on the high cycle fatigue behavior of metallic alloys using finite element simulations of polycrystalline aggregates. It is well known that the microstructure strongly affects the average fatigue strength and when the cyclic stress level is close to the fatigue limit, it is often seen as the main source of the huge scatter generally observed in this fatigue regime. The presence of geometrical defects in a material can also strongly alter the fatigue behavior. Nonetheless, when the defect size is small enough, i.e. under a critical value, the fatigue strength is no more affected by the defect. The so-called Kitagawa effect can be interpreted as a competition between the crack initiation mechanisms governed either by the microstructure or by the defect. Surprisingly, only few studies have been done to date to explain the Kitagawa effect from the point of view of this competition, even though this effect has been extensively investigated in the literature. The primary focus of this paper is hence on the use of both FE simulations and explicit descriptions of the microstructure to get insight into how the competition between defect and microstructure operates in HCF. In order to account for the variability of the microstructure in the predictions of the macroscopic fatigue limits, several configurations of crystalline orientations, crystal aggregates and defects are studied. The results of each individual FE simulation are used to assess the response at the macroscopic scale thanks to a probabilistic fatigue criterion proposed by the authors in previous works. The ability of this criterion to predict the influence of defects on the average and the scatter of macroscopic fatigue limits is evaluated. In this paper, particular emphasis is also placed on the effect of different loading modes (pure tension, pure torsion and combined tension and torsion) on the experimental and predicted fatigue strength of a 316 stainless steel containing artificial defect.

show abstract

Section: Results and Discussion Of The Fatigue Testssupporting

confidence: 93%

Competition between microstructure and defect in multiaxial high cycle fatigue

Morel¹,

Guerchais²,

Saintier³

2015

Frattura Ed Integrità Strutturale

View full text Add to dashboard Cite

show abstract

“…Hence, initiation occurs in the material matrix.This change in damage mechanism as a function of the applied loading condition (i.e. torsion or bending) has also been observed and discussed by Endo and Murakami [21] For the untreated material loaded in shear with defects of 100µm in radius, observations…”

Section: Shear Loadssupporting

confidence: 64%

The effect of quenching and defects size on the HCF behaviour of Boron steel

Pessard

Abrivard

Morel

et al. 2014

International Journal of Fatigue

View full text Add to dashboard Cite

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. AbstractThis work investigates the effect of natural and artificial surface defects and quenching on the fatigue strength of a Boron Steel (22MnB5). A vast experimental campaign has been undertaken to study the high cycle fatigue behaviour and more specifically the fatigue damage mechanisms observed in quenched and untreated materials, under different loading conditions and with differents artificial defects sizes (from 25µm to 370 µm radius). In order to test the sheet metal in shear an original test apparatus is used. The critical defect size is determined to be 100±50µm. This critical size does not appear to depend on the loading type or the microstructure of the material (i.e. ferritic-perlitic or martensitic). However, for large defects, the quenched material is more sensitive to the defect size than the untreated material. For a defect size range of 100µm to 300µm the slope of the Kitagawa-Takahashi diagram is approximately -1/3 and -1/6 for the quenched and untreated materials respectively. A probabilistic approach that leads naturally to a probabilistic Kitagawa type diagram is developed. This methodology can be used to explain the relationship between the influence of the heat treatment and the defect size on the fatigue behaviour of this steel.

show abstract

“…Majumdar et al, [23] Narasaiah et al, [24] and Endo and Murakami [25] have shown that crack initiation could also occur while the strain amplitudes are kept below the fatigue limit, but these cracks would not propagate and are, thus, called nonpropagating cracks. However, there are no reports on the corresponding dislocation structures near the fatigue limit to the best of our knowledge.…”

Section: Discussionmentioning

confidence: 99%

The Study of Fatigue Behaviors and Dislocation Structures in Interstitial-Free Steel

Shih

Huang

2010

Metall Mater Trans A

View full text Add to dashboard Cite

There are three types of cyclic hardening for cyclically deformed interstitial-free (IF) steels. The magnitude of cyclic hardening was unobvious and dislocation cells smaller than 2 lm were very hard to find when total strain amplitude (De/2) was controlled to within 0.1 pct. When De/2 is increased to 0.125 to 0.3 pct, secondary cyclic hardening takes place prior to fatigue failure. De/2 = 0.6 pct, following an initial rapid-hardening stage. Dislocation cells smaller than 2 lm tend to develop near grain boundaries and triple junction of the grains while cycling just above De/2 = 0.125 pct. Such dislocation development results in secondary hardening. However, no failure occurs if cycling just below De/2 = 0.1 pct; hence, the fatigue limit for IF steel should be very close to De/2 = 0.1 pct.

show abstract

Effects of an Artificial Small Defect on Torsional Fatigue Strength of Steels

Cited by 57 publications

References 0 publications

Competition between microstructure and defect in multiaxial high cycle fatigue

Competition between microstructure and defect in multiaxial high cycle fatigue

The effect of quenching and defects size on the HCF behaviour of Boron steel

The Study of Fatigue Behaviors and Dislocation Structures in Interstitial-Free Steel

Contact Info

Product

Resources

About