The fatigue behaviour of three-dimensional stress concentrations

Bellett, Daniel; Taylor, David; Marco, Stefano Di; Mazzeo, Ezio; Guillois, Jerome; Pircher, Thomas

doi:10.1016/j.ijfatigue.2004.07.006

Cited by 143 publications

(92 citation statements)

References 24 publications

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“…Since, in situations of practical interest, the actual orientation of such crystallographic planes is never known, by using the Volume Method argument [2,8,42,43] the hypothesis can be formed that a macroscopic stress/strain state representative of the fatigue damage extent in those grains situated in the vicinity of the notch apex can be estimated by simply averaging the elasto-platic stress over the fatigue process zone (i.e., over the so-called structural volume). Further, according to the TCD (see Ref.…”

Section: Point Methods and Structural Volumementioning

confidence: 99%

Notch and mean stress effect in fatigue as phenomena of elasto-plastic inherent multiaxiality

Susmel

Atzori

Meneghetti

et al. 2011

Engineering Fracture Mechanics

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The present paper summarises an attempt of estimating fatigue lifetime of notched metallic materials by directly accounting for the degree of multiaxiality of the local elasto-plastic stress/strain fields acting on the fatigue process zone. In more detail, the proposed approach takes as its starting point the assumption that Stage I is the most important stage to be modelled to accurately estimate fatigue damage, and this holds true independently of the sharpness of the assessed geometrical feature. According to this initial idea, and by taking full advantage of the socalled Modified Manson-Coffin Curve Method (MMCCM), the hypothesis is then formed that the crack initiation plane is always coincident with that material plane experiencing the maximum shear strain amplitude. Subsequently, to devise an efficient design method capable of taking into account the detrimental effect of stress/strain gradients arising also from severe stress/strain concentration phenomena, the MMCCM is suggested here as being applied in terms of the Theory of Critical Distances (TCD), the latter being used in the form of the Point Method (PM). Further, in light of the well-known fact that the value of the mean stress/strain components in the vicinity of the stress/strain raisers' apices can be different from the corresponding nominal values due to the actual elasto-plastic behaviour of the material being assessed, it is shown, through the MMCCM itself, that also the mean stress effect can directly and accurately be treated as a problem of inherent multiaxiality. Finally, as a preliminary validation, the accuracy and reliability of the proposed approach is checked through several experimental results taken from the literature and generated by testing, under uniaxial fatigue loading, samples containing a variety of geometrical features, the effect of different nominal load ratios being investigated as well.

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Section: Point Methods and Structural Volumementioning

confidence: 99%

Notch and mean stress effect in fatigue as phenomena of elasto-plastic inherent multiaxiality

Susmel

Atzori

Meneghetti

et al. 2011

Engineering Fracture Mechanics

View full text Add to dashboard Cite

show abstract

“…Rather, fatigue is influenced by the stress distribution ahead of the stress concentration and, therefore, on the stress gradient [1,8,11]. The idea was initially put forward during the middle of the previous century by Neuber [13] and Peterson [14].…”

Section: The Theory Of Critical Distances (Tcd)mentioning

confidence: 99%

“…A method which is akin to Peterson's approach considers the maximum principal stress σ p(max) at a single point (point method), at a distance of L/2 from the tip of the notch, as shown in Fig. 1(a) [1,11]. A somewhat different method is the line method, which averages the maximum principal stresses σ p(max) along a line of length 2L, as shown in Fig.…”

Section: The Theory Of Critical Distances (Tcd)mentioning

confidence: 99%

“…While the previously mentioned methods are suitable for tackling 2D geometries, for 3D applications, Taylor and his co-workers [1] have proposed the use of the volume method, which relies on averaging principal stresses over a hemisphere centred at the tip of the notch with a radius of 1.54L.…”

Section: The Theory Of Critical Distances (Tcd)mentioning

confidence: 99%

“…The constants 1.32 and 1.54, associated with the area and volume methods, respectively, arise from the area and volume integration of the crack tip singular stress fields [1].…”

Section: The Theory Of Critical Distances (Tcd)mentioning

confidence: 99%

See 2 more Smart Citations

Fatigue analysis of riveted railway bridge connections using the theory of critical distances

Righiniotis

Imam

Chryssanthopoulos

2008

Engineering Structures

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Crack initiation and propagation analysis at welds – assessing the total fatigue life of complex structures

Baumgartner

Waterkotte

2015

Materialwissenschaft Werkst

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The fatigue strength of complex welded structures may differ highly from that of a simple test specimen. The reason for this observation is in most cases the high amount of crack propagation on the total fatigue life. The aim of this work is to describe the complex failure mechanism with a two-phase model. In this model, the crack initiation and crack propagation phase are assessed separately. The fatigue life until initiation of a crack is derived by notch stresses, calculated using stress averaging or the critical distance approach. The macro crack propagation is determined by fracture mechanics. The methods, which are available to determine the fatigue life until crack initiation, lead to reliable results. The determination of stress intensity factors proved to be demanding. Variations were observed depending on the calculation approach used. For application in industry, the applied approaches should be improved further.Keywords: Weld start and stop position / crack initiation / crack propagation Das Schwingfestigkeitsverhalten von komplexen Bauteilen unterscheidet sich in vielen Fällen stark von dem einfacher Proben. Diese meist im Abgleich zwischen Berechnung und experimenteller Prüfung gemachte Beobachtung kann häufig über den hohen Anteil des Rissfortschritts an der Gesamtlebensdauer erklärt werden. Ziel dieses Beitrags ist es, das komplexe Schwingfestigkeitsverhalten über ein zwei-Phasen Modell zu beschreiben, in dem die Anriss-und die Rissfortschrittsphase separat betrachtet werden. Die Anrissschwingspielzahl wird hierbei über den Spannungsmittelungs-und Spannungsabstandsansatz berechnet, die anschließende Rissfortschrittsphase über bruchmechanische Methoden. In einer Gegenüberstellung von experimentell ermittelter und berechneter Lebensdauer zeigte sich eine gute Übereinstimmung für das Versagenskriterium technischer Anriss. Bei der bruchmechanischen Bewertung erwies sich die Berechnung der Spannungsintensitätsfaktoren als nicht trivial. Für die industrielle Anwendbarkeit empfiehlt sich daher eine Erweiterung und Optimierung der zur Verfügung stehenden numerischen Werkzeuge. Mat.-wiss. u. Werkstofftech. 2015, 46, No. 2 Crack initiation and propagation analysis at welds

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The fatigue behaviour of three-dimensional stress concentrations

Cited by 143 publications

References 24 publications

Notch and mean stress effect in fatigue as phenomena of elasto-plastic inherent multiaxiality

Notch and mean stress effect in fatigue as phenomena of elasto-plastic inherent multiaxiality

Fatigue analysis of riveted railway bridge connections using the theory of critical distances

Crack initiation and propagation analysis at welds – assessing the total fatigue life of complex structures

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