Competition between microstructure and defect in multiaxial high cycle fatigue
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 s...
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Gruppo Italiano Frattura
2015-07-01
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| Series: | Fracture and Structural Integrity |
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| Online Access: | http://www.gruppofrattura.it/pdf/rivista/numero33/numero_33_art_45.pdf |
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| author | F. Morel R. Guerchais N. Saintier |
| author_facet | F. Morel R. Guerchais N. Saintier |
| author_sort | F. Morel |
| collection | DOAJ |
| description | 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. |
| format | Article |
| id | doaj-art-26cf8fa728d74d8f82a130e27dc9c1cd |
| institution | Kabale University |
| issn | 1971-8993 1971-8993 |
| language | English |
| publishDate | 2015-07-01 |
| publisher | Gruppo Italiano Frattura |
| record_format | Article |
| series | Fracture and Structural Integrity |
| spelling | doaj-art-26cf8fa728d74d8f82a130e27dc9c1cd2025-01-02T23:01:25ZengGruppo Italiano FratturaFracture and Structural Integrity1971-89931971-89932015-07-01933404414Competition between microstructure and defect in multiaxial high cycle fatigueF. Morel0R. Guerchais1N. Saintier2LAMPA, Arts et Métiers ParisTech,FranceLMS, Ecole Polytechnique, Palaiseau, FranceI2M, Arts et Métiers ParisTech, Talence, FranceThis 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.http://www.gruppofrattura.it/pdf/rivista/numero33/numero_33_art_45.pdfHigh cycle fatigueMultiaxial loadingDefectPolycrystalline aggregateProbabilistic fatigue criterion |
| spellingShingle | F. Morel R. Guerchais N. Saintier Competition between microstructure and defect in multiaxial high cycle fatigue Fracture and Structural Integrity High cycle fatigue Multiaxial loading Defect Polycrystalline aggregate Probabilistic fatigue criterion |
| title | Competition between microstructure and defect in multiaxial high cycle fatigue |
| title_full | Competition between microstructure and defect in multiaxial high cycle fatigue |
| title_fullStr | Competition between microstructure and defect in multiaxial high cycle fatigue |
| title_full_unstemmed | Competition between microstructure and defect in multiaxial high cycle fatigue |
| title_short | Competition between microstructure and defect in multiaxial high cycle fatigue |
| title_sort | competition between microstructure and defect in multiaxial high cycle fatigue |
| topic | High cycle fatigue Multiaxial loading Defect Polycrystalline aggregate Probabilistic fatigue criterion |
| url | http://www.gruppofrattura.it/pdf/rivista/numero33/numero_33_art_45.pdf |
| work_keys_str_mv | AT fmorel competitionbetweenmicrostructureanddefectinmultiaxialhighcyclefatigue AT rguerchais competitionbetweenmicrostructureanddefectinmultiaxialhighcyclefatigue AT nsaintier competitionbetweenmicrostructureanddefectinmultiaxialhighcyclefatigue |