liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Evaluation and prediction of crack length in a Ni-based superalloy for sustained loading
Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, The Institute of Technology.
Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, The Institute of Technology.
2014 (English)Manuscript (preprint) (Other academic)
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.

Place, publisher, year, edition, pages
2014.
Keyword [en]
Fatigue crack propagation, Inconel 718, Sustained load, Hold time effects, Crack length evaluation
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:liu:diva-104813OAI: oai:DiVA.org:liu-104813DiVA: diva2:699339
Available from: 2014-02-27 Created: 2014-02-27 Last updated: 2014-02-27Bibliographically approved
In thesis
1. Modelling of fatigue crack propagation in Inconel 718 under hold time conditions
Open this publication in new window or tab >>Modelling of fatigue crack propagation in Inconel 718 under hold time conditions
2014 (English)Licentiate thesis, comprehensive summary (Other academic)
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.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2014. 48 p.
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1645
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-104814 (URN)10.3384/lic.diva-104814 (DOI)978-91-7519-403-5 (ISBN)
Presentation
2014-03-21, A34, Hus A, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2014-02-27 Created: 2014-02-27 Last updated: 2014-03-14Bibliographically approved

Open Access in DiVA

No full text

Authority records BETA

Lundström, ErikSimonsson, Kjell

Search in DiVA

By author/editor
Lundström, ErikSimonsson, Kjell
By organisation
Solid MechanicsThe Institute of Technology
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 85 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf