Multiaxial fatigue behaviour of laserbeam-welded thin steel and aluminium sheets under proportional and non-proportional combined loading

Wiebesiek, J.; Störzel, Klaus; Bruder, Thomas; Kaufmann, Heinz

doi:10.1016/j.ijfatigue.2010.12.008

Cited by 30 publications

(23 citation statements)

References 7 publications

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“…4, [8] and for seam-welded flange-tubes [1,9], Fig. 5; for laserbeam-welded ductile steel tube-tube joints same tendencies are determined [10,11], too. Due to the stress gradients in machined or weld notches local stress/strain states are also deformationcontrolled as long as the structural yield-point [12] is not exceeded.…”

Section: Methods For Presenting Multiaxial Fatigue Resultsmentioning

confidence: 64%

“…9 [17]. For laserbeam-welded overlapped tube-tube joints of wrought aluminum with e = 17%, a decrease of fatigue life in the medium fatigue range is determined [1,11], but a neutral behaviour is obtained with seam welded flange-tube joints of aluminum with a lower value e = 13% resulting from coarser grains, Fig. 10 [18].…”

Section: Methods For Presenting Multiaxial Fatigue Resultsmentioning

confidence: 99%

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Influence of Material Ductility on Fatigue Life under Multiaxial Proportional and Non-Proportional Normal and Shear Stresses

Sonsino

2019

MATEC Web Conf.

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Current experiences show that a non-proportional loading of ductile materials such as wrought steels, wrought aluminium or magnesium alloys, not welded or welded, causes a significant fatigue life reduction under an out-of-phase shear strain or shear stress superimposed on a normal strain or normal stress compared with proportional in-phase loading. However, when ductility, here characterised by tensile elongation, is reduced by a heat treatment or by another manufacturing technology such as casting or sintering, the afore-mentioned life reduction is compensated or even inversed, i. e. longer fatigue life results compared with proportional loading. Some actual results, determined with additive manufactured titanium, suggest that microstructural features such as manufacturing-dependent internal defects like microporosities should be considered in addition to the ductility level. This complex life behaviour under non-proportional loading cannot always be estimated. Therefore, in experimental proofs of multiaxial loaded parts, especially safety-critical components or structures, with real or service-like signals, emphasis must be placed on retaining non-proportionalities between loads and stresses/strains, respectively.

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Section: Methods For Presenting Multiaxial Fatigue Resultsmentioning

confidence: 64%

Section: Methods For Presenting Multiaxial Fatigue Resultsmentioning

confidence: 99%

Influence of Material Ductility on Fatigue Life under Multiaxial Proportional and Non-Proportional Normal and Shear Stresses

Sonsino

2019

MATEC Web Conf.

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“…In recent literatures of multiaxial fatigue, it is reported that fatigue life evaluated by the Mises stress is overestimated [1][2][3][4][5][6][7][8] and the M magnitude depends on loading path [9][10][11][12][13][14][15][16]. In the multiaxial fatigue under non-proportional loading in which directions of principal stress and strain are changed in a cycle, it has been reported that fatigue lives are reduced accompanying with additional hardening which depends on both loading path and material [4][5][6][7][8][9][10][11][12][13][14][15][16]. In addition, Itoh et al presented a strain parameter for life evaluation under non-proportional loading considering the intensity of non-proportionality and the material dependency [12,14].…”

Section: Introductionmentioning

confidence: 99%

Multiaxial fatigue property of type 316 stainless steel using hollow cylinder specimen under combined pull loading and inner pressure

Morishita¹,

Takada²,

Itoh³

2017

Frattura Ed Integrità Strutturale

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ABSTRACT. Stress controlled multiaxial fatigue test was carried out using a hollow cylinder specimen of type 316 stainless steel. A newly developed fatigue testing machine which can apply push-pull loading and reversed torsion loading and inner pressure to the hollow cylinder specimen was employed. 5 types of cyclic loading paths were employed by combining zero to pull axial and hoop stresses: a Pull (only axial stress), an Inner-pressure (only hoop stress), an Equi-biaxial (equi-biaxial stress by axial and hoop stresses), a Square-shape (trapezoidal waveforms of axial and hoop stresses with 90-degree phase difference) and a L-shape (alternately axial stress and hoop stress) loading paths. Since directions of principal stresses are fixed in all the tests, all of the loading paths are classified into 'proportional loading'. In the Pull, the Inner-pressure and the Equi-biaxial tests, fatigue lives can be correlated on a unique line by a maximum equivalent stress based on von Mises. On the other hand, fatigue lives in the Square-shape and the L-shape tests were reduced comparing with that in the other tests, which was caused by yielding of larger plastic deformation.

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“…For the case of failure at weld root, a fatigue assessment concept covering both geometrical and statistical size effects was presented in [7]. Many research activities have been initiated during the last years for the investigation of fatigue design of multiaxially loaded welded joints [8][9][10]. Nevertheless, the case of weld ends under such loading is not sufficiently explored yet.…”

Section: Introductionmentioning

confidence: 99%

Sharp three-dimensional notches under combined nominal normal and shear fatigue loading

Vormwald¹,

Shams²

2017

Frattura Ed Integrità Strutturale

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ABSTRACT. Many engineering structures are exposed to non-proportional fatigue loading. However, at the critical location of crack initiation, often only one of the load sequences dominates -the individual load cases result in different crack initiation sites. Based on engineering judgment a simplified local uniaxial or proportional loading situation may be assessed. In general, the critical location must be identified by calculating fatigue lives for a variety of locations. The position of the critical location depends on the hypothesis applied for life calculation -besides loading, geometry, material and many other influence factors. For sharp three-dimensional notches the region for the search of the critical location may be restricted considerably. Weld start and stop points are an industrial example for such sharp notches. They are the object of the present investigation. They are exposed to nominal normal and shear loading. The individual hot spots for crack initiation lie necessarily close together. A strong interaction of the loading cases for both proportional and non-proportional loading was experimentally observed. In the numerical investigation notch stresses were calculated using an idealised weld end model. Based on the critical plane approach according to Findley, numerical interaction lines were produced.

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Multiaxial fatigue behaviour of laserbeam-welded thin steel and aluminium sheets under proportional and non-proportional combined loading

Cited by 30 publications

References 7 publications

Influence of Material Ductility on Fatigue Life under Multiaxial Proportional and Non-Proportional Normal and Shear Stresses

Influence of Material Ductility on Fatigue Life under Multiaxial Proportional and Non-Proportional Normal and Shear Stresses

Multiaxial fatigue property of type 316 stainless steel using hollow cylinder specimen under combined pull loading and inner pressure

Sharp three-dimensional notches under combined nominal normal and shear fatigue loading

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