Please use this identifier to cite or link to this item: https://doi.org/10.15480/882.2124
DC FieldValueLanguage
dc.contributor.authorCiavarella, Michele-
dc.contributor.authorPapangelo, Antonio-
dc.date.accessioned2019-03-25T09:10:11Z-
dc.date.available2019-03-25T09:10:11Z-
dc.date.issued2018-04-01-
dc.identifier.citationFrattura ed Integrita Strutturale 44 (12): 49-63 (2018-04-01)de_DE
dc.identifier.issn1971-8993de_DE
dc.identifier.urihttp://hdl.handle.net/11420/2207-
dc.description.abstractAs often done in design practice, the Wöhler curve of a specimen, in the absence of more direct information, can be crudely retrieved by interpolating with a power-law curve between static strength at a given conventional low number of cycles N0(of the order of 10-103), and the fatigue limit at a “infinite life”, also conventional, typically N∞=2·106or N∞=107cycles. These assumptions introduce some uncertainty, but otherwise both the static regime and the infinite life are relatively well known. Specifically, by elaborating on recent unified treatments of notch and crack effects on infinite life, and using similar concepts to the static failure cases, an interpolation procedure is suggested for the finite life region. Considering two ratios, i.e. toughness to fatigue threshold FK=KIc/∆Kth, and static strength to endurance limit, FR=σR/∆σ0, qualitative trends are obtained for the finite life region. Paris’ and Wöhler’s coefficients fundamentally depend on these two ratios, which can be also defined “sensitivities” of materials to fatigue when cracked and uncracked, respectively: higher sensitivity means stringent need for design for fatigue. A generalized Wöhler coefficient, k’, is found as a function of the intrinsic Wöhler coefficient k of the material and the size of the crack or notch. We find that for a notched structure, k<k’<m, as a function of size of the notch: in particular, k’=k holds for small notches, then k’ decreases up to a limiting value (which depends upon Ktfor mildly notched structures, or on FKand FRonly for severe notch or crack). A perhaps surprising return to the original slope k is found for very large blunt notches. Finally, Paris’ law should hold for a distinctly cracked structure, i.e. having a long-crack; indeed, Paris’ coefficient m is coincident with the limiting value of k’lim. The scope of this note is only qualitative and aims at a discussion over unified treatments in fatigue.en
dc.language.isoende_DE
dc.relation.ispartofFrattura ed integrità strutturalede_DE
dc.rightsinfo:eu-repo/semantics/openAccess-
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.subjectFatiguede_DE
dc.subjectWöhler curvede_DE
dc.subjectNotch Sensitivityde_DE
dc.subjectParis’ lawde_DE
dc.subjectAshby mapsde_DE
dc.subject.ddc600: Technikde_DE
dc.titleOn notch and crack size effects in fatigue, Paris’ law and implications for Wöhler curvesde_DE
dc.typeArticlede_DE
dc.identifier.urnurn:nbn:de:gbv:830-882.029112-
dc.identifier.doi10.15480/882.2124-
dc.type.diniarticle-
dc.subject.ddccode600-
dcterms.DCMITypeText-
tuhh.identifier.urnurn:nbn:de:gbv:830-882.029112-
tuhh.oai.showtruede_DE
tuhh.abstract.englishAs often done in design practice, the Wöhler curve of a specimen, in the absence of more direct information, can be crudely retrieved by interpolating with a power-law curve between static strength at a given conventional low number of cycles N0(of the order of 10-103), and the fatigue limit at a “infinite life”, also conventional, typically N∞=2·106or N∞=107cycles. These assumptions introduce some uncertainty, but otherwise both the static regime and the infinite life are relatively well known. Specifically, by elaborating on recent unified treatments of notch and crack effects on infinite life, and using similar concepts to the static failure cases, an interpolation procedure is suggested for the finite life region. Considering two ratios, i.e. toughness to fatigue threshold FK=KIc/∆Kth, and static strength to endurance limit, FR=σR/∆σ0, qualitative trends are obtained for the finite life region. Paris’ and Wöhler’s coefficients fundamentally depend on these two ratios, which can be also defined “sensitivities” of materials to fatigue when cracked and uncracked, respectively: higher sensitivity means stringent need for design for fatigue. A generalized Wöhler coefficient, k’, is found as a function of the intrinsic Wöhler coefficient k of the material and the size of the crack or notch. We find that for a notched structure, k<k’<m, as a function of size of the notch: in particular, k’=k holds for small notches, then k’ decreases up to a limiting value (which depends upon Ktfor mildly notched structures, or on FKand FRonly for severe notch or crack). A perhaps surprising return to the original slope k is found for very large blunt notches. Finally, Paris’ law should hold for a distinctly cracked structure, i.e. having a long-crack; indeed, Paris’ coefficient m is coincident with the limiting value of k’lim. The scope of this note is only qualitative and aims at a discussion over unified treatments in fatigue.de_DE
tuhh.publisher.doi10.3221/IGF-ESIS.44.05-
tuhh.publication.instituteStrukturdynamik M-14de_DE
tuhh.identifier.doi10.15480/882.2124-
tuhh.type.opus(wissenschaftlicher) Artikel-
tuhh.institute.germanStrukturdynamik M-14de
tuhh.institute.englishStrukturdynamik M-14de_DE
tuhh.gvk.hasppnfalse-
openaire.rightsinfo:eu-repo/semantics/openAccessde_DE
dc.type.driverarticle-
dc.type.casraiJournal Article-
tuhh.container.issue44de_DE
tuhh.container.volume12de_DE
tuhh.container.startpage49de_DE
tuhh.container.endpage63de_DE
dc.rights.nationallicensefalsede_DE
item.languageiso639-1en-
item.fulltextWith Fulltext-
item.openairetypeArticle-
item.grantfulltextopen-
item.creatorOrcidCiavarella, Michele-
item.creatorOrcidPapangelo, Antonio-
item.openairecristypehttp://purl.org/coar/resource_type/c_6501-
item.creatorGNDCiavarella, Michele-
item.creatorGNDPapangelo, Antonio-
item.cerifentitytypePublications-
crisitem.author.deptStrukturdynamik M-14-
crisitem.author.deptStrukturdynamik M-14-
crisitem.author.orcid0000-0001-6271-0081-
crisitem.author.orcid0000-0002-0214-904X-
crisitem.author.parentorgStudiendekanat Maschinenbau-
crisitem.author.parentorgStudiendekanat Maschinenbau-
Appears in Collections:Publications with fulltext
Files in This Item:
File Description SizeFormat
2009-Article text (.pdf, max 100 Mb )-7205-1-10-20180318.pdfVerlags-PDF902,04 kBAdobe PDFThumbnail
View/Open
Show simple item record

Page view(s)

162
Last Week
2
Last month
2
checked on Oct 20, 2020

Download(s)

129
checked on Oct 20, 2020

Google ScholarTM

Check

Note about this record

Export

This item is licensed under a Creative Commons License Creative Commons