Fatigue assessment of welded joints by local approaches

Radaj, Dieter; Sonsino, Cetin Morris; Fricke, Wolfgang

doi:10.1533/9781845691882

Cited by 398 publications

(589 citation statements)

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“…Nominalno se naprezanje određuje pomoću klasične mehanike konstrukcija zanemarujući lokalne utjecaje poput koncentracije naprezanja unutar detalja, koji se u tom slučaju uzimaju u obzir na strani otpornosti. Ako se radi o geometrijski složenijemu detalju ili je detalj opterećen složenim stanjem naprezanja, primjenjuju se lokalni pristupi poput pristupa preko hot spot naprezanja ili efektivnoga naprezanja u zarezu [1,2]. Lokalne procjene umora temelje se na proračunu naprezanja na očekivanu mjestu nastanka pukotine, uzimajući pri tome u obzir lokalne utjecaje.…”

Section: Uvodunclassified

Fatigue life assessment by using local Hot Spot approach

Fuštar¹,

Lukačević²,

Dujmović³

2017

Zajednički Temelji 2017 - Peti Skup Mladih Istraživača Iz Područja Građevinarstva I Srodnih Tehničkih Znanosti - Zbornik Radova

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SažetakPrilikom procjene preostaloga životnog vijeka čeličnih detalja izloženih umoru najčešće se zbog jednostavnosti proračuna primjenjuje S-N metoda uz globalni pristup preko nominalnih naprezanja. Ta metoda na strani djelovanja zanemaruje lokalne utjecaje poput koncentracija naprezanja uzrokovanih lokalnom promjenom u geometriji detalja. Ovi se utjecaji indirektno uzimaju na strani otpornosti pomoću eksperimentalno dobivenih S-N krivulja. Ako se radi o geometrijski složenijemu detalju ili je detalj opterećen složenim stanjem naprezanja, primjenjuju se lokalni pristupi kojima se prilikom proračuna uzimaju u obzir lokalni utjecaji. Ovaj rad prikazuje procjenu životnoga vijeka zavarenoga čeličnog detalja dodatne lamele izloženog umoru. Detalj je sastavni dio čelične konstrukcije željezničkoga mosta, a procjena se provodi lokalnim pristupom preko hot spot naprezanja. Naprezanja se određuju mjerenjem deformacija na određe-nim mjestima u detalju zbog prolaza karakterističnih vlakova. Karakteristični vlakovi sastavni su dio modela opterećenja formiranoga prema podacima Hrvatskih željeznica. Na taj se način proračunava životni vijek zavarenoga detalja zbog umora, a rezultati se uspoređuju sa životnim vijekom istoga detalja dobivenog pristupom preko nominalnih naprezanja. Ključne riječi: životni vijek zbog umora, lokalni pristup Hot Spot naprezanja, zavareni detalj Fatigue life assessment by using local Hot Spot approach AbstractDuring the assessment of remaining fatigue life of the welded details that are prone to fatigue, S-N method with global nominal stress approach is the most common method due to its simplicity. This method neglects local action effects such as stress concentrations due to local geometry changes in detail. These effects are indirectly included on the resistance side trough experimentally obtained S-N curves. In cases of more complex detail or if the detail is loaded with a complex stress state, local approaches which take local effects into account during calculations are used. This paper presents a fatigue life assessment of fatigue prone cover plate welded steel detail. Detail is a part of the steel railway bridge structure and assessment is made by local hot spot stress approach. Stresses are determined based on strain measurements on specific locations in the detail, due to the passage of characteristic trains. Characteristic trains are an integral part of a load model formed by data from Croatian Railways. Accordingly, the fatigue life of the welded detail is calculated and the results are compared with fatigue life of the same detail which is determined based on the nominal stress approach.

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Section: Uvodunclassified

Fatigue life assessment by using local Hot Spot approach

Fuštar¹,

Lukačević²,

Dujmović³

2017

Zajednički Temelji 2017 - Peti Skup Mladih Istraživača Iz Područja Građevinarstva I Srodnih Tehničkih Znanosti - Zbornik Radova

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“…Usually, the weld profile is assumed to be circular for type 1, circular or triangular for type 2, and triangular for type 3 weldments with fillets on toes connecting with parent plates. A vast quantity of researches reviewed in [1,2,3,4] has been devoted to investigation of effects produced by these parameters on residual life. Designations of parameters for type 3 weldment profile and applied bending moment, according to [26,27] In the present study, the geometry of the weld profile for type 3 weldment is more completely specified in order to investigate its as-welded, dressed and intermediate configurations.…”

Section: Geometrical Relationsmentioning

confidence: 99%

“…Therefore, creep and fatigue characteristics of welded joints are of a priority importance for long-term integrity assessments and design of welded structures. There were many attempts to develop analytical tools [1,2,3,4] to estimate long-term strength of welded joints under variable loading. However, residual life assessments are frequently complicated and inaccurate because of complex material microstructure and too many parameters affecting the strength of welded joints.…”

Section: Introductionmentioning

confidence: 99%

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On creep-fatigue endurance of TIG-dressed weldments using the linear matching method

Gorash

Chen

2013

Engineering Failure Analysis

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This version is available at https://strathprints.strath.ac.uk/44578/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output.On creep-fatigue endurance of TIG-dressed weldments using the linear matching method AbstractThis paper is devoted to parametric study on creep-fatigue endurance of the steel type 316N(L) weldments at 550 • C identified as type 3 according to R5 Vol. 2/3 procedure classification. The study is implemented using a direct method known as the Linear Matching Method (LMM) and based upon the creep-fatigue evaluation procedure considering time fraction rule for creep-damage assessment. Seven configurations of the weldment, characterised by particular values of a geometrical parameter ρ, are proposed. Parameter ρ, which represents different grades of TIG dressing, is a ratio between the radius of the fillet of the remelted metal on a weld toe and the thickness of welded plates. For each configuration, the total number of cycles to failure N ⋆ in creep-fatigue conditions is assessed numerically for different loading cases defined by normalised bending momentM and dwell period ∆t. The obtained set of N ⋆ is extrapolated by the analytic function dependent onM, ∆t and parameter ρ. Proposed function for N ⋆ shows good agreement with numerical results obtained by the LMM. Therefore, it is used for the identification of Fatigue Strength Reduction Factors (FSRFs) effected by creep, which are intended for design purposes, and dependent on ∆t and ρ.

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“…This metal is commonly used in ship building. To predict fatigue life of welded joints, several recommendations have already been proposed by many authors [1,2]. However, we have proposed an approach which takes into account the main weld characteristics and fatigue crack initiation.…”

Section: Introductionmentioning

confidence: 99%

Fatigue crack initiation in naval welded joints: experimental and numerical approaches

Thévenet

Lautrou

Cognard

2008

Proc Appl Math and Mech

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This work deals with the fatigue behavior of welded joints. The proposed strategy can be split into two stages: the structure shakedown study and the fatigue crack initiation study. Firstly, stabilized elastic stress-strain cycles are obtained in any point of the welded joint by a finite element analysis, taking constant or variable amplitude loadings into account. The second part of this work is the calculation of the fatigue crack initiation period. Under the assumption of a fast elastic shakedown, a recent approach, proposed by Lemaitre et al., based on damage mechanics, can be used to predict the fatigue crack initiation life in a structure subjected to variable and complex loadings. This strategy is used as a post-treatment of the shakedown finite element calculation for the studied welded specimen. As a validation, four-point bending fatigue tests under constant amplitude loading were carried out on welded specimens provided by DCNS group. Good correlations between experimental and calculated fatigue crack initiation lives have been established.

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Fatigue assessment of welded joints by local approaches

Cited by 398 publications

References 0 publications

Fatigue life assessment by using local Hot Spot approach

Fatigue life assessment by using local Hot Spot approach

On creep-fatigue endurance of TIG-dressed weldments using the linear matching method

Fatigue crack initiation in naval welded joints: experimental and numerical approaches

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