Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • 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
A fracture mechanical life prediction method for rolling contact fatigue based on the asperity point load mechanism
KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.).
KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.).ORCID iD: 0000-0001-6896-1834
2012 (English)In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 83, 62-74 p.Article in journal (Refereed) Published
Abstract [en]

The purpose was to develop a fracture mechanics based method for determining the life of surface initiated rolling contact fatigue or spalling. The life simulations were based on the asperity point load mechanism, a mode I crack growth assumption and LEFM. The life prediction was verified against the spalling life in some gear teeth, which had been measured for the simulation data. The computational tool required an equivalent mixed-mode life parameter. Such are suggested in the literature and some of these were evaluated. Also, the work required material properties for crack growth at stress cycles with highly compressive minimum loads. An experimental series was performed for crack growth at R < 0. Negative crack closure limits K-I,K-cl were suggested by the compliance but not the crack growth rate. Simulations with small negative closure limits (K-I,K-cl = -0.1 MPa root m) predicted the spalling life in the gears. It was however noted that the life predictions depended more on K-I,K-cl than the equivalent mixed-mode life parameter.

Place, publisher, year, edition, pages
2012. Vol. 83, 62-74 p.
Keyword [en]
Rolling contact fatigue, Spalling, Asperity, Crack closure, Fatigue life, Plane mixed-mode
National Category
Applied Mechanics
Identifiers
URN: urn:nbn:se:kth:diva-95123DOI: 10.1016/j.engfracmech.2011.12.012ISI: 000302515000006Scopus ID: 2-s2.0-84857916030OAI: oai:DiVA.org:kth-95123DiVA: diva2:526782
Funder
Swedish Research Council
Note
QC 20120515Available from: 2012-05-15 Created: 2012-05-14 Last updated: 2017-12-07Bibliographically approved
In thesis
1. On fatigue crack growth modelling of surface initiated rolling contact fatigue using the asperity point load mechanism
Open this publication in new window or tab >>On fatigue crack growth modelling of surface initiated rolling contact fatigue using the asperity point load mechanism
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Load transfer in applications or between machine components is generally achieved through contact. In case of recurrent high contact loads in combination with a rolling motion, i.e. with a relatively small amount of slip, the contact surface may eventually suffer from rolling contact fatigue (RCF). The damage consists then of cracks and craters or spalls, which can cause dysfunctionality of the application leading to inefficiency or increased maintenance costs. Ultimately the damage may cause total failure of the machine component. The damage process is still not fully understood due to the complexity of the problem. Different mechanisms have been suggested to explain initiation and propagation of RCF damage. The current work focused on crack growth modelling of surface initiated RCF in case hardened gear steel. The study was based on the asperity point load mechanism, which emphasizes the importance of the surface roughness in the damage process. Asperities on the contact surface act as stress raisers inducing locally high tensile surface stress when entering the contact. Improved understanding of the damage process and further validation of the asperity point load mechanism was achieved.

In Paper A, the crack path of surface initiated RCF was simulated in the symmetry plane of the damage with the trajectory of the largest principal stress in the uncracked material. The mode I fracture mechanism was found applicable as well as linear elastic fracture mechanics (LEFM). The evolvement of the asperity contact parameters during the load cycle was determined through a finite element (FE) contact model based on an equivalent contact geometry. The predicted RCF crack path agreed with experimental spall profiles both in entry details as in overall shape. An experimental series was performed in Paper B to investigate the crack closure behaviour in presence of large negative minimum loads. The experimental results suggested a crack closure limit close to zero. The choice of the equivalent mixed-mode stress intensity factor range and especially the crack closure limit had a significant effect on the predicted RCF or spalling life. The two-dimensional crack growth model was further developed in Paper C and used to investigate the influence of asperity size, friction and residual surface stress on the simulated RCF damage. The simulations agreed qualitatively with experimental observations where reduced surface roughness, improved lubrication and compressive residual surface stress increased RCF resistance. In Paper D, a three-dimensional stationary crack was studied using an FE model and a simplified RCF load. A new crack geometry was proposed allowing the investigation of the spall opening angle of the typical vshaped damage. Crack arrest through crack closure was suggested as explaining mechanism. A qualitative study indicated increased spread of the surface damage with increased friction. The results also depended on the crack inclination angle. The different studies supported the asperity point load mechanism to explain not only fatigue initiation but also fatigue crack propagation.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. 46 p.
Series
TRITA-HFL. Report / Royal Institute of Technology, Solid Mechanics, ISSN 1654-1472 ; 0551
National Category
Applied Mechanics
Identifiers
urn:nbn:se:kth:diva-141151 (URN)978-91-7501-999-4 (ISBN)
Public defence
2014-02-20, Sal F3, Lindstedtsvägen 26, KTH, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20140210

Available from: 2014-02-10 Created: 2014-02-10 Last updated: 2014-02-10Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Authority records BETA

Alfredsson, Bo

Search in DiVA

By author/editor
Hannes, DaveAlfredsson, Bo
By organisation
Solid Mechanics (Dept.)
In the same journal
Engineering Fracture Mechanics
Applied Mechanics

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 94 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • 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