Evaluation of notched fatigue strength at elevated temperature by linear notch mechanics

Chen, Qiang; Kawagoishi, Norio; Nisitani, Hironobu

doi:10.1016/s0142-1123(99)00081-x

Cited by 26 publications

(25 citation statements)

References 10 publications

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“…[13][14][15][16][17] Some authors have gone further on this topic, investigating the interactive creep-fatigue crack growth, obtaining very good results. [18] Kawagoishi and coworkers [19,20] investigated the strength of nickel-base superalloy Inconel 718 under rotating banding loading at room temperature and 500 C in air. The applicability of linear notch mechanics to the evaluation of notched fatigue strength at elevated temperature was assessed in terms of the fatigue limit for crack initiation and that for crack growth.…”

Section: Introductionmentioning

confidence: 99%

Advanced Materials for Applications at High Temperature: Fatigue Assessment by Means of Local Strain Energy Density

Gallo

Berto

2015

Adv Eng Mater

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The interest on fatigue assessment of steel and other alloys at high temperature has increased continuously in the last years. However, high cycle fatigue of notched components at high temperature has not been deeply investigated experimentally and theoretically. The present paper investigates the accuracy of Strain Energy Density (SED) averaged over a control volume approach when applied to high-temperature fatigue data from notched components. In the present work, a large bulk of high-temperature fatigue data, taken from the literature and regarding notched components made of different advanced materials, is reanalyzed. In detail: C45 carbon steel at 250°C, Inconel 718 at 500°C, and directionally solidified superalloy DZ125 at 850°C are considered. The main advantage of SED averaged over a control volume is that different geometries can be summarized in a single narrow scatter band. From an industrial viewpoint, the use of a geometry-independent parameter (and fatigue curve) leads to a considerable advantage in terms of time and cost

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Section: Introductionmentioning

confidence: 99%

Advanced Materials for Applications at High Temperature: Fatigue Assessment by Means of Local Strain Energy Density

Gallo

Berto

2015

Adv Eng Mater

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“…In [57,58], the notched fatigue strength of the nickelbase superalloy Inconel 718 was investigated under rotating bending loading at room temperature and 500°C in air. The linear notch mechanics was employed to assess the fatigue strength at elevated temperature being for that material the small-scale yielding conditions satisfied also at elevated temperature.…”

Section: High Temperature Atigue Behaviour O Cr Steelsmentioning

confidence: 99%

Some recent results on the fatigue strength of notched specimens made of 40CrMoV13.9 steel at room and high temperature

Berto

2015

Phys Mesomech

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The work summarizes a large bulk of experimental data from specimens made of 40CrMoV13.9 steel. The first part of the paper deals with multiaxial fatigue strength of notched round bars tested under combined tension and torsion loading, both in-phase and out-of-phase. The results from multi-axial tests are discussed together with those obtained under pure tension and pure torsion loading from notched specimens with the same geometry. The second part of the paper summarizes data from uniaxial-tension stress-controlled fatigue tests on specimens made of the same steel. Tests are performed varying temperature, from room temperature up to 650°C. Altogether more than 180 new fatigue data are summarised in the present work, corresponding to more than two-years of testing programme. All fatigue data are presented first in terms of nominal stress amplitudes referred to the net area and then re-analysed in terms of the mean value of the strain energy density evaluated over a given, crescent shape volume embracing the stress concentration region. For the specific steel, the radius of the control volume is found to be independent of the loading mode

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“…17,19 Figure 7 displays the stress-distance curves, at the endurance limit condition, for the notched specimens of Inconel 718 tested by Chen et al 17 The value for the critical distance shown in this chart (i.e. For the sake of completeness, it is worth observing here that the values for the net stress concentration factors estimated according to this standard numerical procedure (refer to Tables 2 and 3) were slightly different from the corresponding values reported in the original sources.…”

Section: H I G H -C Y C L E F a T I G U E S T R E N G T H O F N O T Cmentioning

confidence: 99%

“…In this context, towards the end of the 1990s, Nisitani and co-workers 17,18 have shown that, also at elevated temperatures, the high-cycle fatigue strength of notched specimens of Inconel 718 could successfully be estimated via conventional linear-elastic notch mechanics, the small-yielding conditions being satisfied for this specific material also at 300, 500 and 600°C. On the contrary, little research work has been carried out so far in order to formalise and validate appropriate design methods suitable for designing against high-cycle fatigue notched metallic components experiencing high temperatures during inservice operations.…”

Section: Introductionmentioning

confidence: 99%

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The linear‐elastic Theory of Critical Distances to estimate high‐cycle fatigue strength of notched metallic materials at elevated temperatures

Louks

Susmel

2014

Fatigue Fract Eng Mat Struct

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This paper investigates the accuracy of the linear‐elastic Theory of Critical Distances (TCD) in estimating high‐cycle fatigue strength of notched metallic materials experiencing elevated temperatures during in‐service operations. The TCD postulates that the fatigue damage extent can be estimated by directly post‐processing the entire linear‐elastic stress field acting on the material in the vicinity of the crack initiation locations. The key feature of this theory is that the high‐cycle fatigue assessment is based on a scale length parameter that is assumed to be a material property. The accuracy of this design method was checked against a number of experimental results generated, under axial loading, by testing, at 250 °C, notched specimens of carbon steel C45. To further investigate the reliability of the TCD, its accuracy was also checked via several data taken from the literature, these experimental results being generated by testing notched samples of Inconel 718 at 500 °C as well as notched specimens of directionally solidified superalloy DZ125 at 850 °C. This validation exercise allowed us to prove that the linear‐elastic TCD is successful in estimating high‐cycle fatigue strength of notched metallic materials exposed to elevated temperature, resulting in estimates falling within an error interval of ±20%. Such a high level of accuracy suggests that, in situations of practical interest, reliable high‐cycle fatigue assessment can be performed without the need for taking into account those non‐linearities characterising the mechanical behaviour of metallic materials at high temperature, the used critical distance being still a material property whose value does not depend on the sharpness of the notch being designed.

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Evaluation of notched fatigue strength at elevated temperature by linear notch mechanics

Cited by 26 publications

References 10 publications

Advanced Materials for Applications at High Temperature: Fatigue Assessment by Means of Local Strain Energy Density

Advanced Materials for Applications at High Temperature: Fatigue Assessment by Means of Local Strain Energy Density

Some recent results on the fatigue strength of notched specimens made of 40CrMoV13.9 steel at room and high temperature

The linear‐elastic Theory of Critical Distances to estimate high‐cycle fatigue strength of notched metallic materials at elevated temperatures

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