Study on the Correction of S-N Distribution in the Welding Fatigue Analysis Method Based on the Battelle Equivalent Structural Stress by Rough Set Theory

Sun, Yibo; Yang, Xinhua

doi:10.5545/sv-jme.2013.1579

Cited by 6 publications

(8 citation statements)

References 10 publications

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“…On the basis of the two stage crack growth mode, the R effects on the stress intensity factor range can be included either in the first stage of the crack growth or the second stage of the crack growth. Especially, the effects of the stress ratio R is more dominant when a crack is very small, or dominated by the first stage of the crack growth governed by exponent n in the present two-stage growth mode of Equation (5). It is important to point out that the stress ratio R effects on crack growth rate are much stronger if R is negative than the positive R while there is no negative stress ratio R in the well-documented data used in this paper, which remains to be investigated hereafter.…”

Section: Discussionmentioning

confidence: 86%

“…The mean S-N curves and deviation curves with −3, −2, −1, +1, +2, and +3 magnifications were then carried out in respective coordinates, as shown in Figures 2-4 [5]. According to the parameters above, the S-N data points based on NS, SS, and ES, respectively, were discretized as shown in Figures 2-4.…”

Section: Establishment Of the S-n Curvementioning

confidence: 99%

“…Due to the fact that it ignores the local stress effects of welded joints and is explicitly mathematically explained, many standard specifications have been established based on the nominal stress method using a large scale of experimental data from [3,4]. While some limitations have gradually come to light, the nominal stress of a complex structure is hard to determine and inconsistent stress calculation is caused by a singularity in the weld toe as well, which limit its universality in engineering applications [5]. Afterwards, in order to obtain the accurate stress in the welding toe, the hot spot stress (HSS) method that is extrapolated based on the nominal stress was first proposed by Niemi [6].…”

Section: Introductionmentioning

confidence: 99%

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Evaluation Model of Aluminum Alloy Welded Joint Low-Cycle Fatigue Data Based on Information Entropy

Liu

Zou

Sun

et al. 2017

Entropy

Self Cite

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An evaluation model of aluminum alloy welded joint low-cycle fatigue data based on information entropy is proposed. Through calculating and analyzing the information entropy of decision attributes, quantitative contribution of stress concentration, plate thickness, and loading mode to the fatigue destruction are researched. Results reveal that the total information entropy of the fatigue data based on nominal stress, structural stress and equivalent structural stress are, respectively, 0.9702, 0.8881, and 0.8294. There is consistency between the reducing trend of the weight-based information entropy and the smaller and smaller standard deviation of the S-N curves. In the structural stress based S-N curve, total stress concentration factor is crucial for the distribution of the fatigue data and the weight based information entropy of membrane stress concentration factor is 0.6754, which illustrates that stress concentration is a key issue of welded structure to which ought to be attached great importance. Subsequently, in the equivalent structural stress-based S-N curve, the weight based information entropy of stress ratio is 0.5759, which plays an important role in the distribution of fatigue data. With the importance level of the attributes on the S-N curves investigated, the correction of R in the equivalent structural stress based master S-N curve method should be carried out to make the welding fatigue prediction much more accurate.

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Section: Discussionmentioning

confidence: 86%

Section: Establishment Of the S-n Curvementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evaluation Model of Aluminum Alloy Welded Joint Low-Cycle Fatigue Data Based on Information Entropy

Liu

Zou

Sun

et al. 2017

Entropy

Self Cite

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“…The slope of At present, the main approaches used for steel bridge fatigue life evaluation [5][6][7] include the nominal stress approach, the extrapolation hot spot stress approach, and equivalent structural stress approach. The nominal stress approach has been applied to some bridge design codes [8,9], but it adopts different S-N curves for different welded joint types, and it is difficult to determine the location of nominal stress points of complex structure joints accurately with this approach [10]. The extrapolated hot spot stress approach [11,12] only needs a unified S-N curve for different welded joints.…”

Section: Appl Sci 2019 9 X For Peer Review 2 Of 25mentioning

confidence: 99%

Influence of Weld Parameters on the Fatigue Life of Deck-Rib Welding Details in Orthotropic Steel Decks Based on the Improved Stress Integration Approach

et al. 2019

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Fatigue cracks in orthotropic steel decks (OSDs) have been a serious problem of steel bridges for a long time. The structural stress approach is an important approach for fatigue life evaluation of welded structures. Firstly, two parameters and the mesh sensitivity of the stress-based integration equivalent structural stress approach (stress integration approach for short) are analyzed in this paper. Then, the applicability of the master S-N curve is verified based on experimental data of the deck-rib welding details in OSDs. Finally, the multi-scale finite element model (FEM) of Jiangyin Bridge is established, and the bridge fatigue life calculation steps based on the stress integration approach are given. The influence of the slope of the master S-N curve at high cycles on the bridge fatigue life is discussed. Further, the weld parameter influences on the bridge fatigue life are analyzed, as including the following: (1) The determination of the influence of the weld size changes caused by weld manufacturing errors on the bridge fatigue life; (2) the proposal of a new grinding treatment type, and the analysis of influence of the grinding radius on fatigue life; and (3) a comparison of the fatigue life of the deck-rib welding details under 80% partial penetration and 100% full penetration. The results show that the structural stress calculated by the stress integration approach does not change significantly with the parameters of the isolation body width w and the distance δ between the crack propagation surface and the reference surface. To simplify the calculation, δ is set as 0, and w can be set as the mesh size along the weld length direction. The mesh size of the stress integration approach is recommended as 0.25 times the deck thickness. The slope of the master S-N curve at high cycles significantly affects the bridge fatigue life, and a slope of 5 is reasonable. The weld parameter studies for the deck-rib welding details in the OSD of Jiangyin Bridge show that the change of weld size caused by manufacturing errors can obviously affect the bridge fatigue life, and the fatigue life of five different weld types varies from 51 years to 113 years. The new grinding treatment type, without weakening the deck, is beneficial to improving the bridge fatigue life. The fatigue life increases by approximately 5% with an increase of the grinding radius of 2 mm. The fatigue life of 80% partial penetration is slightly higher than that of 100% full penetration.

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“…In welding techniques, failure is a key problem that is related to the stability and safety of the welded structure. 6 The fatigue properties of welded structures are function of welding material, shape of the welded structure, radius of weld toe, weld angle, height of the reinforcement, and welding quality. [7][8][9][10] With respect to the studies on the fatigue in aluminum alloy weldments, most literature discussed the fatigue behaviors of weldments prepared by the molten welding methods, such as inert-gas metal-arc welding, 11 TIG welding, [12][13][14] and friction stir welding.…”

Section: Introductionmentioning

confidence: 99%

Fatigue properties of 6061-T6 aluminum alloy butt joints processed by vacuum brazing and tungsten inert gas welding

Lin

Hwang

Fung

2016

Advances in Mechanical Engineering

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Tungsten inert gas welding and vacuum brazing butt joints of Al-Mg-Si alloy 6061 in the artificially aged condition T6 were studied. Constant amplitude and variable amplitude fatigue loading tests were performed. The experimental S-N curves were compared with the fatigue design curves recommended by the International Institute of Welding, British Standard, and Eurocode 9. Two mean stress correction methods, Goodman and Gerber, were evaluated. In terms of the size effect on the fatigue life, this article proposed an innovational thickness correction method based on the ratio of the ultimate tensile strengths of specimens with different thickness. For vacuum brazing components, the tensile strengthbased thickness correction method was better than the thickness correction methods recommended by the International Institute of Welding and Eurocode 9.

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Study on the Correction of S-N Distribution in the Welding Fatigue Analysis Method Based on the Battelle Equivalent Structural Stress by Rough Set Theory

Cited by 6 publications

References 10 publications

Evaluation Model of Aluminum Alloy Welded Joint Low-Cycle Fatigue Data Based on Information Entropy

Evaluation Model of Aluminum Alloy Welded Joint Low-Cycle Fatigue Data Based on Information Entropy

Influence of Weld Parameters on the Fatigue Life of Deck-Rib Welding Details in Orthotropic Steel Decks Based on the Improved Stress Integration Approach

Fatigue properties of 6061-T6 aluminum alloy butt joints processed by vacuum brazing and tungsten inert gas welding

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