Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • 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
Estimation of fatigue life by using a cyclic plasticity model and multiaxial notch correction
Linköping University, Department of Management and Engineering, Solid Mechanics.
2019 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Mechanical components often possess notches. These notches give rise to stress concentrations, which in turn increases the likelihood that the material will undergo yielding. The finite element method (FEM) can be used to calculate transient stress and strain to be used in fatigue analyses. However, since yielding occurs, an elastic-plastic finite element analysis (FEA) must be performed. If the loading sequence to be analysed with respect to fatigue is long, the elastic-plastic FEA is often not a viable option because of its high computational requirements.

In this thesis, a method that estimates the elastic-plastic stress and strain response as a result of input elastic stress and strain using plasticity modelling with the incremental Neuber rule has been derived and implemented. A numerical methodology to increase the accuracy when using the Neuber rule with cyclic loading has been proposed and validated for proportional loading. The results show fair albeit not ideal accuracy when compared to elastic-plastic finite element analysis. Different types of loading have been tested, including proportional and non-proportional as well as complex loadings with several load reversions.

Based on the computed elastic-plastic stresses and strains, fatigue life is predicted by the critical plane method. Such a method has been reviewed, implemented and tested in this thesis. A comparison has been made between using a new damage parameter by Ince and an established damage parameter by Fatemi and Socie (FS). The implemented algorithm and damage parameters were evaluated by comparing the results of the program using either damage parameter to fatigue experiments of several different load cases, including non-proportional loading. The results are fairly accurate for both damage parameters, but the one by Ince tend to be slightly more accurate, if no fitted constant to use in the FS damage parameter can be obtained.

Place, publisher, year, edition, pages
2019. , p. 75
Keywords [en]
Multiaxial load, fatigue, notch, elastic-plastic, stress-strain, non-proportional load, incremental Neuber, damage parameter
National Category
Applied Mechanics
Identifiers
URN: urn:nbn:se:liu:diva-158095ISRN: LIU-IEI-TEK-A--19/03505--SEOAI: oai:DiVA.org:liu-158095DiVA, id: diva2:1329866
External cooperation
Volvo Construction Equipment
Subject / course
Solid Mechanics
Supervisors
Examiners
Available from: 2019-06-26 Created: 2019-06-25 Last updated: 2019-06-26Bibliographically approved

Open Access in DiVA

fulltext(2593 kB)41 downloads
File information
File name FULLTEXT01.pdfFile size 2593 kBChecksum SHA-512
dcc770a0d9a2d54fb8949a26cafd2f922ba35469a04be9c818d968f0fbac1fb5cd94452d55dfb6c8673afb5ad7633a726230e84cc10ea0f4ff370c98e8f83cd3
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Johansson, Nils
By organisation
Solid Mechanics
Applied Mechanics

Search outside of DiVA

GoogleGoogle Scholar
Total: 41 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 122 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • 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