liu.seSearch for publications in DiVA
Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Modelling of fatigue crack propagation in Inconel 718 under hold time conditions
Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, Hållfasthetslära. Linköpings universitet, Tekniska högskolan.
2014 (engelsk)Licentiatavhandling, med artikler (Annet vitenskapelig)
Abstract [en]

In this thesis an investigation and modelling of the fatigue crack propagation in the nickel based superalloy Inconel 718, with a special emphasis on the effect of hold times, is presented. The modelling work has been concentrated on describing the hold time fatigue crack propagation by using the concept of a damaged zone in front of the crack tip, which is believed to have a lowered resistance against crack propagation.

The modelling framework is built on physically motivated parameters, which are all easy to calibrate through one specially designed test type. Later evaluation through many experimental tests has also shown that the model is capable, within reasonable scatter level to predict, the hold time fatigue crack propagation for many different temperatures and loading conditions. Further evaluation of a complex flight spectrum, with the incorporation of crack closure within the model, was also predicted with a satisfying result.

This thesis is divided into two parts. First, a background and a somewhat deeper discussion of the modelling of fatigue crack growth under hold time conditions is presented. The second part consists of ve appended papers, which describe the work completed so far in the project.

sted, utgiver, år, opplag, sider
Linköping: Linköping University Electronic Press, 2014. , s. 48
Serie
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1645
HSV kategori
Identifikatorer
URN: urn:nbn:se:liu:diva-104814DOI: 10.3384/lic.diva-104814ISBN: 978-91-7519-403-5 (tryckt)OAI: oai:DiVA.org:liu-104814DiVA, id: diva2:699351
Presentation
2014-03-21, A34, Hus A, Campus Valla, Linköpings universitet, Linköping, 10:15 (engelsk)
Opponent
Veileder
Tilgjengelig fra: 2014-02-27 Laget: 2014-02-27 Sist oppdatert: 2014-03-14bibliografisk kontrollert
Delarbeid
1. High temperature fatigue crack growth behaviour of Inconel 718 under hold time and overload conditions
Åpne denne publikasjonen i ny fane eller vindu >>High temperature fatigue crack growth behaviour of Inconel 718 under hold time and overload conditions
2013 (engelsk)Inngår i: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 48, s. 178-186Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Inconel 718 is a frequently used material for gas turbine applications at temperatures up to 650°C. For such components, the main load cycle is typically defined by the start-up and shut-down of the engine. In this main loading cycle, hold times at high temperature are commonly present in critical components. These high temperature hold times may greatly increase the fatigue crack growth rate with respect to the number of cycles unless other beneficial factors such as for example initial overloads are present. The latter can be caused by abnormal service conditions but can also occur on a more regular basis and are then typically observed in components with strong thermal transients during engine start-up. In this paper, focus has been placed on the effect of overloads on the hold time fatigue crack growth behaviour and its subsequent description. More specifically, crack propagation in Inconel 718 has been studied at the temperatures 550°C and 650°C with and without an overload at the start of the cycle. The effect of initial overloads was found to be substantial. A simple model for describing the effect of these loading conditions has also been developed based on the concept of the damaged zone, present around the crack tip. Irregular crack fronts and unbroken ligaments left on the fracture surfaces seen in complementary microscopy studies seem to support this approach. Furthermore, the stress state in front of a crack tip in a 2D model was investigated both with and without an initial overload. The results were related to the observed crack growth retardation behaviour found in the material testing.

sted, utgiver, år, opplag, sider
Elsevier, 2013
Emneord
Nickel-base superalloys, fatigue crack propagation, Inconel 718, hold times, grain boundary embrittlement, crack propagation modelling, Finite Element modelling
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-85931 (URN)10.1016/j.ijfatigue.2012.10.018 (DOI)000315617500020 ()
Tilgjengelig fra: 2013-03-13 Laget: 2012-12-03 Sist oppdatert: 2017-12-07bibliografisk kontrollert
2. Modelling of high temperature fatigue crack growth in Inconel 718 under hold time conditions
Åpne denne publikasjonen i ny fane eller vindu >>Modelling of high temperature fatigue crack growth in Inconel 718 under hold time conditions
2013 (engelsk)Inngår i: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 52, s. 124-130Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Inconel 718 is a frequently used material for gas turbine applications at temperatures up to 650 °C. The main load cycle for such components is typically defined by the start-up and shut-down of the engine. It generally includes hold times at high temperatures, which have been found to have a potential for greatly increasing the fatigue crack growth rate with respect to the number of load cycles. However, these effects may be totally or partly cancelled by other load features, such as overloads or blocks of continuous cyclic loading, and the actual crack propagation rate will therefore depend on the totality of features encompassed by the load cycle. It has previously been shown that the increased crack growth rate found in hold time experiments can be associated with a damage evolution, where the latter is not only responsible for the rapid intergranular crack propagation during the actual hold times, but also for the increased crack growth during the load reversals. In this paper, modelling of the hold time fatigue crack growth behaviour of Inconel 718 has been carried out, using the concept of a damaged zone as the basis for the treatment. With this conceptually simple and partly novel approach, it is shown that good agreement with experimental results can be found.

sted, utgiver, år, opplag, sider
Elsevier, 2013
Emneord
Nickel-base superalloys, fatigue crack propagation, Inconel 718, hold times, grain boundary embrittlement, crack propagation modelling
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-85933 (URN)10.1016/j.ijfatigue.2013.03.004 (DOI)000318831300013 ()
Tilgjengelig fra: 2012-12-03 Laget: 2012-12-03 Sist oppdatert: 2017-12-07bibliografisk kontrollert
3. A load history dependent model for fatigue crack propagation in Inconel 718 under hold time conditions
Åpne denne publikasjonen i ny fane eller vindu >>A load history dependent model for fatigue crack propagation in Inconel 718 under hold time conditions
2014 (engelsk)Inngår i: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 118, s. 17-30Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Modelling of high temperature fatigue crack growth in Inconel 718 under the interaction of fast cyclic loading and hold times at maximum load has been conducted. A model, based on the concept of a damaged zone in front of the crack tip has been applied for three different temperatures, 550, 600 and 650 ◦C, with good agreement for both calibration and validation tests. A statistical evaluation of 22 tests in total was also conducted, which shows that the developed model gives a reasonable scatter factor at a probability of failure of 0.1 %.

sted, utgiver, år, opplag, sider
Elsevier, 2014
Emneord
Fatigue crack propagation, Inconel 718, Hold time effects, Crack growth modelling, Statistics
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-104809 (URN)10.1016/j.engfracmech.2014.02.005 (DOI)000334819600002 ()
Tilgjengelig fra: 2014-02-27 Laget: 2014-02-27 Sist oppdatert: 2017-12-05bibliografisk kontrollert
4. Modelling of fatigue crack growth in Inconel 718 under hold time conditions - application to a flight spectrum
Åpne denne publikasjonen i ny fane eller vindu >>Modelling of fatigue crack growth in Inconel 718 under hold time conditions - application to a flight spectrum
2014 (engelsk)Inngår i: Advanced Materials Research, ISSN 1662-8985, Vol. 891-892, s. 759-764Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Gas turbine operating cycles at high temperatures often consist of load reversals mixed with hold times; the latter occurring either as cruise for aero engines or at continuous power output for land based turbines, but also at low frequency loading conditions, e.g. slow “ramp up” of engine thrust. The hold time conditions cause the crack to grow by intergranular fracture due to material damage near the crack tip, thus rapidly increasing the crack growth rate. Since the damaged zone will affect the crack propagation rate due to cyclic loadings as well, the complete load history of a component therefore has to be considered. The crack propagation model presented in this paper is based on the damaged zone concept, and considers the history effect in the form of damaged zone build up during hold times, and subsequent destruction as the crack propagates onwards by rapidly applied load reversals. By incorporating crack closure for handling different R-values, an aero engine component spectrum is evaluated for a surface crack at 550 C. The result shows a good correlation to model simulation, despite the complexity of the load spectrum.

sted, utgiver, år, opplag, sider
Trans Tech Publications Inc., 2014
Emneord
Fatigue crack propagation, Inconel 718, Hold time effects, Crack growth modelling
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-104812 (URN)10.4028/www.scientific.net/AMR.891-892.759 (DOI)000337767700118 ()
Tilgjengelig fra: 2014-02-27 Laget: 2014-02-27 Sist oppdatert: 2016-05-18bibliografisk kontrollert
5. Evaluation and prediction of crack length in a Ni-based superalloy for sustained loading
Åpne denne publikasjonen i ny fane eller vindu >>Evaluation and prediction of crack length in a Ni-based superalloy for sustained loading
2014 (engelsk)Manuskript (preprint) (Annet vitenskapelig)
Abstract [en]

Crack length evaluations for sustained loading have been conducted on Inconel 718 surface crack specimens for 550 and 650 ◦C. Hold times, e.g. slow ramp up of engine thrust, sustained load as continuous power output for stationary gas turbines or as cruise for aero engines, have been seen to result in material damage at the crack tip, causing the crack to grow by intergranular fracture and resulting in a strong increase of the crack growth rate. Here, sustained load tests as well as specially designed hold time tests are used to measure crack length and the size of the damaged zone (material damage) in front of the crack tip by comparing potential drop (PD) predictions with visible post-mortem beach marks on the fracture surface. Fracture surfaces were also investigated with scanning electron microscope (SEM), showing what the damaged zone most likely consists of. In addition, by applying a crack propagation model based on the damaged zone concept, crack length and damaged zone evaluations were conducted. The results show that the damaged zone must be taken into consideration, when evaluating post-mortem fracture surfaces if the test has included hold time loads, both when setting up post-mortem calibration curves and when evaluating crack propagation models.

Emneord
Fatigue crack propagation, Inconel 718, Sustained load, Hold time effects, Crack length evaluation
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-104813 (URN)
Tilgjengelig fra: 2014-02-27 Laget: 2014-02-27 Sist oppdatert: 2014-02-27bibliografisk kontrollert

Open Access i DiVA

Modelling of fatigue crack propagation in Inconel 718 under hold time conditions(2504 kB)1099 nedlastinger
Filinformasjon
Fil FULLTEXT01.pdfFilstørrelse 2504 kBChecksum SHA-512
0b70b409d072c0700caed2bfc448e552510873a107d5d2810c8dc2a26e00ebf8a8c37d17ea4ca6f93b3566515291cb3481b0e98a105edbd9ec48063fe2cb17a3
Type fulltextMimetype application/pdf
omslag(422 kB)87 nedlastinger
Filinformasjon
Fil COVER01.pdfFilstørrelse 422 kBChecksum SHA-512
2313fb658a4074117764de1976f55b2a49a98882bb75c2b7d67420896a9c951248a1121b5f3919f1bc38b330f060a338ad1cd70e8cd1bc8b390fa0fc9d6f4cda
Type coverMimetype application/pdf

Andre lenker

Forlagets fulltekst

Personposter BETA

Lundström, Erik

Søk i DiVA

Av forfatter/redaktør
Lundström, Erik
Av organisasjonen

Søk utenfor DiVA

GoogleGoogle Scholar
Totalt: 1099 nedlastinger
Antall nedlastinger er summen av alle nedlastinger av alle fulltekster. Det kan for eksempel være tidligere versjoner som er ikke lenger tilgjengelige

doi
isbn
urn-nbn

Altmetric

doi
isbn
urn-nbn
Totalt: 951 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf