Notch stress concepts for the fatigue assessment of welded joints – Background and applications

Sonsino, Cetin Morris; Fricke, Wolfgang; Bruyne, F. de; Hoppe, Alexander; Ahmadi, Majid; Zhang, G.

doi:10.1016/j.ijfatigue.2010.04.011

Cited by 189 publications

(111 citation statements)

References 10 publications

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“…Righiniotis [7] used the theory of critical distances (TCD) to perform fatigue analysis of a riveted railway bridge by a global-local FE (Finite element) model. Sonsino [8] applied notch stress concept for several engineering structures including MAG-welded offshore K-nodes, sandwich panels for ship decks, spot-welded automotive doors and MAG-welded automotive trailing links.…”

Section: Introductionmentioning

confidence: 99%

Wind-Induced Fatigue Analysis of High-Rise Steel Structures Using Equivalent Structural Stress Method

Fang

et al. 2017

Applied Sciences

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Abstract:Welded beam-to-column connections of high-rise steel structures are susceptive to fatigue damage under wind loading. However, most fatigue assessments in the field of civil engineering are mainly based on nominal stress or hot spot stress theories, which has the disadvantage of dependence on the meshing styles and massive curves selected. To address this problem, in this paper, the equivalent structural stress method with advantages of mesh-insensitive quality and capability of unifying different stress-life curves (S-N curves) into one is introduced to the wind-induced fatigue assessment of a large-scale complicated high-rise steel structure. The multi-scale finite element model is established and the corresponding wind loading is simulated. Fatigue life assessments using equivalent structural stress method, hot spot stress method and nominal stress method are performed, and the results are verified and comparisons are made. The mesh-insensitive quality is also verified. The results show that the lateral weld toe of the butt weld connecting the beam flange plate and the column is the location where fatigue damage most likely happens. Nominal stress method considers fatigue assessment of welds in a more global way by averaging all the stress on the weld section while in equivalent structural stress method and hot spot method local stress concentration can be taken into account more precisely.

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Section: Introductionmentioning

confidence: 99%

Wind-Induced Fatigue Analysis of High-Rise Steel Structures Using Equivalent Structural Stress Method

Fang

et al. 2017

Applied Sciences

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“…The notch stress gradient contribution is included; a size effect. The real ρ value can be artificially enlarged employing a fictitious component ρ f = s·ρ * to obtain the effective one ρ e = ρ + ρ f and the corresponding notch stress range S e = Δσ e = Δσ av = Δσ max (ρ e ) of the original geometry at once (Sonsino et al 2012;.…”

Section: Effective Notch Stress or Strain Criterionmentioning

confidence: 99%

“…The ρ r = 0.05 [mm] value has been selected based on a completely different hypothesis, i.e. the relationship between the SIF and notch stress as well as crack tip of a reasonable local stress component (Sonsino et al 2012). Reference radius ρ r has already been proposed to be replaced by a relative one (Schijve 2012), although -at least for weld toe notches -involving the plate thickness seems a better solution than the weld leg length.…”

Section: Effective Notch Stress or Strain Criterionmentioning

confidence: 99%

Fatigue damage criteria classification, modelling developments and trends for welded joints in marine structures

Besten

2018

Ships and Offshore Structures

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Fatigue is typically a governing limit state for marine structures. Welded joints are the weakest links in that respect. Physics involve several resistance dimensions, a range of scales and distinct contributions in different stages of the accumulative damage process. Fatigue damage criteria developed over time have been classified with respect to type of information, geometry, parameter and process zone including plane and life region annotations. The criteria are evaluated regarding model (in)capabilities, showing up to what extent (governing) physics are taken into account. Modelling developments and trends towards complete strength, multi-scale and total life criteria have been identified. Incorporating all four (interacting) fatigue resistance dimensions: material, geometry, loading & response and environment translates into a complete strength fatigue damage criterion. Considering macro-, meso-and micro-scale information provides a multi-scale fatigue damage criterion. Correlation of crack initiation and growth requires matching intact and cracked geometry parameters, revealing a total life fatigue damage criterion. HIGHLIGHTS• Classification of fatigue damage criteria with respect to type of information, geometry, parameter and process zone including plane and life region annotations.• Identification of modelling developments and trends towards complete strength, multi-scale and total life fatigue damage criteria for welded joints in marine structures. NomenclatureA notch strain energy density process zone area C crack growth or fatigue resistance curve intercept (endurance coefficient) D fatigue damage E normal strain at macro-scale E Young's modulus J crack tip energy density J 1 hydrostatic stress or strain component J 2 deviatoric stress or strain component K σ crack tip stress intensity factor K ɛ crack tip strain intensity factor K' work hardening coefficient K N notch stress intensity factor K N I mode-I notch stress intensity factor K N III mode-III notch stress intensity factor K I mode-I stress intensity factor K I T total mode-I stress intensity factor K I r residual mode-I stress intensity factor K III mode-III stress intensity factor K * FE dimensionless FE based notch stress intensity factor N (total) number of cycles until failure N i number of cycles corresponding to initiation N g number of cycles corresponding to growth R notch strain energy density process zone radius S stress based fatigue damage criterion S B Battelle structural normal stress range S e effective notch stress range S eq (equivalent) Von Mises stress range S n nominal stress range S s hot spot structural stress range S T total stress range T temperature T B Battelle structural shear stress range T σS strength scatter band index W energy based fatigue damage criterion W N notch strain energy W N A notch strain energy density Y n notch factor Y f far field factor a crack size (i.e. length) a 0 critical defect size a d long-term corrosion pit size (i.e. depth) a i (real) defect or initial crack size a n (root) not...

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“…In the current literature different methods have been developed based on nominal stress [38,9], hot spot stress [38][39][40][41] or structural stress [42][43][44] and notch stress [19,[45][46][47]. They differentiate amongst one another in the amount of local stress information.…”

Section: Comparative Studymentioning

confidence: 99%

Comparative study of multiaxial fatigue methods applied to welded joints in marine structures

Lieshout¹,

Besten²,

Kaminski³

2016

Frattura Ed Integrità Strutturale

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ABSTRACT. Marine structures are particularly prone to action of waves, winds and currents with stochastically varying composition, intensities and directions. Therefore, resultant stresses may cause multiaxial fatigue in specific welded structural details. For the assessment of multiaxial fatigue in welded joints, a wide variety of methods have been suggested. However, there is still no consensus on a method which can correctly account for non-proportional and variable amplitude loading. This paper beholds a comparative study of multiaxial fatigue methods applicable for design of marine structures. For the purpose of comparison several load cases were defined including non-proportional and variable amplitude loadings with different normal and shear stress amplitude ratios. Three types of methods are compared: those described by three different codes (i.e. Eurocode 3, IIW and DNV-GL), those described by three different multiaxial fatigue approaches from literature (i.e. Modified Carpinteri-Spagnoli Criterion, Modified Wohler Curve Method and Effective Equivalent Stress Hypothesis) and an approach based on Path-Dependent-Maximum-Range multiaxial cycle counting. From this study it has been concluded that non-proportional variable amplitude loading has a significant negative impact on the fatigue lifetime estimates, and that further research and experimental testing are essential to come to a consensus.

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Notch stress concepts for the fatigue assessment of welded joints – Background and applications

Cited by 189 publications

References 10 publications

Wind-Induced Fatigue Analysis of High-Rise Steel Structures Using Equivalent Structural Stress Method

Wind-Induced Fatigue Analysis of High-Rise Steel Structures Using Equivalent Structural Stress Method

Fatigue damage criteria classification, modelling developments and trends for welded joints in marine structures

Comparative study of multiaxial fatigue methods applied to welded joints in marine structures

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