Fatigue performance of tungsten inert gas (TIG) and plasma welds in thin sections

Branco, C.M.; Maddox, S J; Infante, V.; Gomes, Edgar C.

doi:10.1016/s0142-1123(98)00084-x

Cited by 26 publications

(13 citation statements)

References 7 publications

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“…If we consider the 3‐mm‐thick load‐carrying fillet‐welded joints tested by Branco, 32 characterized by k 1 = 1.417, we have a eff = 1.509 mm from expression , which is only three times greater than a N 0 . Then, similarly to the short crack effect illustrated by the well‐known Kitagawa diagram, 62 Fig.…”

Section: Discussionmentioning

confidence: 95%

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The peak stress method applied to fatigue assessments of steel and aluminium fillet‐welded joints subjected to mode I loading

Meneghetti

2008

Fatigue Fract Eng Mat Struct

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A B S T R A C TThe aim of this work is to present an engineering method based on linear elastic finite element (FE) analyses oriented to fatigue strength assessments of fillet-welded joints made of steel or aluminium alloys and subjected to mode I loading in the weld toe region where fatigue cracks nucleate. The proposed approach combines the robustness of the notch stress intensity factor approach with the simplicity of the so-called 'peak stress method'. Fatigue strength assessments are performed on the basis of (i) a well-defined elastic peak stress evaluated by FE analyses at the crack initiation point (design stress) and (ii) a unified scatter band (design fatigue curve) dependent on the class of material, i.e. structural steel or aluminium alloys. The elastic peak stress is calculated by using rather coarse meshes with a fixed FE size. A simple rule to calculate the elastic peak stress is also provided if a FE size different from that used in the present work is adopted. The method can be applied to joints having complex geometry by adopting a two-step analysis procedure that involves standard finite element (FE) models like those usually adopted in an industrial context. The proposed approach is validated against a number of fatigue data published in the literature.Keywords coarse mesh; fatigue design; fillet-welded joints; finite element analysis; local approaches; notch stress intensity factors. N O M E N C L A T U R Ea = crack length, V-notch depth or component's reference dimension a eff = effective component's dimension a 0 = El Haddad-Smith-Topper length parameter a N 0 = characteristic length that depends on a 0 and 2α d = adopted finite element size K I = mode I stress intensity factor K th = threshold range of the mode I stress intensity factor K V I , K V II = mode I, mode II notch stress intensity factor (NSIFs) of a sharp V-notch K V I , K V I I = range of K V I , K V II r, θ = polar coordinates T σ = scatter index defined as the ratio between the fatigue strengths for survival probability of 2.3 and 97.7% at a given number of cycles 2α = V-notch opening angle λ 1 , λ 2 = mode I and mode II eigenvalues in Williams' solution σ n , σ n = nominal stress, range of σ n σ peak , σ peak = linear elastic peak stress calculated by FEM at the sharp V-notch tip by means of a given mesh pattern, range of σ peak σ rr , σ θθ = stress components in a polar frame of reference σ th = fatigue strength at the knee point of a component in terms of nominal stress rangeCorrespondence: G. Meneghetti.

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Section: Discussionmentioning

confidence: 95%

“… Estimation of the reduction of the fatigue limit at 5 million cycles for the 3‐mm‐thick load‐carrying fillet‐welded joint in steel 32 characterized by an effective dimension a eff = 1.509 mm. The fatigue model summarized in the figure is presented elsewhere 23,57 .…”

Section: Discussionmentioning

confidence: 99%

The peak stress method applied to fatigue assessments of steel and aluminium fillet‐welded joints subjected to mode I loading

Meneghetti

2008

Fatigue Fract Eng Mat Struct

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“…On the other hand, thickness correction was applied as defined by the IIW recommendations [12]. It is worth mentioning that some studies have already reported the adjusted data for the thickness effect, such as studies by van Es et al [10] and Branco et al [20]. Therefore, no further thickness adjustments were made for already corrected test data.…”

Section: S-n Curve Slopesmentioning

confidence: 99%

Review of fatigue data for welds improved by tungsten inert gas dressing

Yıldırım

2015

International Journal of Fatigue

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“…Techniques such as: TIG and plasma dressing, burr grinding, needle, shot and hammer peening have been studied in last decades and reported in numerous papers [7][8][9][10][11]. More recently, some attention has been placed on the investigation of high frequency peening treatment, referred to as ultrasonic impact treatment or as ultrasonic peening, that has proved to be an efficient way for fatigue life improvement [12,13].…”

Section: Introductionmentioning

confidence: 99%

Fatigue behaviour of T welded joints rehabilitated by tungsten inert gas and plasma dressing

Ramalho

Ferreira

Branco³

2011

Materials & Design

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This paper concerns a fatigue study on the effect of tungsten inert gas (TIG) and plasma dressing in non-load-carrying fillet welds of structural steel with medium strength. The fatigue tests were performed in three point bending at the main plate under constant amplitude loading, with a stress ratio of R=0.05 and a frequency of 7 Hz.Fatigue results are presented in the form of nominal stress range versus fatigue life (S-N) curves obtained from the as welded joints and the TIG dressing joints at the welded toe. These results were compared with the ones obtained in repaired joints, where TIG and plasma dressing were applied at the welded toes, containing fatigue cracks with a depth of 3-5 mm in the main plate and through the plate thickness. A deficient repair was obtained by TIG dressing, caused by the excessive depth of the crack. A reasonable fatigue life benefits were obtained with plasma dressing. Good results were obtained with the TIG dressing technique for specimens with shallower initial defects (depth lesser than 2.5 mm).The fatigue life benefits were presented in terms of a gain parameter assessed using both experimental data and life predictions based on the fatigue crack propagation law.

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Fatigue performance of tungsten inert gas (TIG) and plasma welds in thin sections

Cited by 26 publications

References 7 publications

The peak stress method applied to fatigue assessments of steel and aluminium fillet‐welded joints subjected to mode I loading

The peak stress method applied to fatigue assessments of steel and aluminium fillet‐welded joints subjected to mode I loading

Review of fatigue data for welds improved by tungsten inert gas dressing

Fatigue behaviour of T welded joints rehabilitated by tungsten inert gas and plasma dressing

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