Analysis of crack propagation in welded stiffened panels

Dexter, Robert J.; Pilarski, Paul; Mahmoud, Hussam

doi:10.1016/j.ijfatigue.2003.08.006

Cited by 43 publications

(27 citation statements)

References 6 publications

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“…A crack propagating perpendicular to stiffeners in M(T) panel is reported to have no effect for extruded integral stringers in AA7075-T6, 51 but to slow down for welded stringers in a steel. 52 Thus, weld residual stresses may in fact be useful, if they can be manipulated in their nature through design. We are looking into such aspects, including modelling on the lines laid down in the literature (e.g.…”

Section: Discussionmentioning

confidence: 99%

Fatigue crack propagation into the residual stress field along and perpendicular to laser beam butt‐weld in aluminium alloy AA6056

Vaidya

Staron

Horstmann

2011

Fatigue Fract Eng Mat Struct

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A B S T R A C T Laser beam butt welds in Al-alloys are very narrow and are accompanied by steep residual stress gradients. In such a case, how the initial crack orientation and the distance of the notch tip relative to the weld affect fatigue crack propagation has not been investigated. Therefore, this investigation was undertaken with two different crack orientations: along the mid-weld and perpendicular to the weld. Fatigue crack propagation 'along the midweld' was found to be faster in middle crack tension specimens than in compact tension specimens. For the crack orientation 'perpendicular to the weld', the relative distance between the notch tip and the weld was varied using compact tension specimens to generate either tensile or compressive residual stresses near the notch tip. When tensile residual stresses were generated near the notch tip, fatigue crack propagation was found to be faster than that in the base material, irrespective of the difference in the initial residual stress level and whether the crack propagated along the mid-weld or perpendicular to the weld. In contrast, when compressive weld residual stresses were generated near the notch tip, fatigue crack arrest, slow crack propagation, multiple crack branching and out of plane deviation occurred. The results are discussed by considering the superposition principle and possible practical implications are mentioned.

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Section: Discussionmentioning

confidence: 99%

Fatigue crack propagation into the residual stress field along and perpendicular to laser beam butt‐weld in aluminium alloy AA6056

Vaidya

Staron

Horstmann

2011

Fatigue Fract Eng Mat Struct

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“…For ship structures, the rectangular width typically ranges from 3.5 to 4 times the plate thickness. Dexter et al performed fatigue tests on half‐scale welded stiffened panel specimens that model a part of a ship deck structure. The authors measured welding residual stresses in stiffened panel specimens and observed that the measured stresses vary mostly between a rectangular shape and a triangular shape .…”

Section: Modelling and Simulation Of Crack Propagation In Welded Stifmentioning

confidence: 99%

“…Dexter et al performed fatigue tests on half‐scale welded stiffened panel specimens that model a part of a ship deck structure. The authors measured welding residual stresses in stiffened panel specimens and observed that the measured stresses vary mostly between a rectangular shape and a triangular shape . Subsequent crack growth simulations showed that the residual stress distribution can be well described by a rectangular shape, where the maximum tensile stress equals to the yield stress of the considered material and compressive stresses between the stiffeners provide the equilibrium of internal forces …”

Section: Modelling and Simulation Of Crack Propagation In Welded Stifmentioning

confidence: 99%

Multiscale fatigue crack growth modelling for welded stiffened panels

Božić

Schmauder

Mlikota

et al. 2014

Fatigue Fract Eng Mat Struct

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A B S T R A C T The influence of welding residual stresses in stiffened panels on effective stress intensity factor (SIF) values and fatigue crack growth rate is studied in this paper. Interpretation of relevant effects on different length scales such as dislocation appearance and microstructural crack nucleation and propagation is taken into account using molecular dynamics simulations as well as a Tanaka-Mura approach for the analysis of the problem. Mode I SIFs, K I , were calculated by the finite element method using shell elements and the crack tip displacement extrapolation technique. The total SIF value, K tot , is derived by a part due to the applied load, K appl , and by a part due to welding residual stresses, K res . Fatigue crack propagation simulations based on power law models showed that high tensile residual stresses in the vicinity of a stiffener significantly increase the crack growth rate, which is in good agreement with experimental results.Keywords dislocation; fatigue crack growth rate; microstructurally small cracks; residual stress. N O M E N C L A T U R Ea = half crack length a 0 = initial crack length a fin = final crack length C = material constant of the Paris equation CRSS = critical resolved shear stress d = slip band length da/dN = crack growth rate E = Young's modulus F → r; t ð Þ = interatomic force F max = maximum applied force F min = minimum applied force G = shear modulus K = stress intensity factor (SIF) K appl = stress intensity factor due to the applied load K res = stress intensity factor due to weld residual stresses K th = stress intensity factor threshold K tot = total stress intensity factor m = atomic mass m = material constant of the Paris equation N = number of stress cycles for the fatigue crack propagation N f = number of stress cycles for fatigue failure N g = number of stress cycles required for crack nucleation in a single grain N ini = number of stress cycles needed for the initiation of a small crack R = stress ratio R eff = effective stress intensity factor ratio U → r ; t ð Þ = interatomic embedded atom method pair potential W c = specific fracture energy per unit area Correspondence: Ž. Božić.

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“…It is recognised that the fatigue life of welded structures is significantly affected by the welding residual stresses [1][2][3][4][5][6][7][8][9][16][17][18][19][20]. Nussbaumer [1,3] studied the propagation of long fatigue cracks in multi-cellular box beams.…”

Section: Residual Stresses In Welded Structuresmentioning

confidence: 99%

“…Dexter et al. [4–7] further observed that the compressive residual stresses between the welded stiffeners significantly retarded the fatigue crack growth rates in the panel, and identified that the restraining effects of the stiffeners played a minor role. In general, the compressive residual stress between the welded stiffeners increases the amount of crack closure and retards the fatigue crack growth rates in the base plate.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation Into the Fatigue of Welded Stiffened 350WT Steel Plates Using Neutron Diffraction Method

Yuen

Taheri‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬

Gharghouri³

2010

Strain

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The propagation of fatigue cracks under constant amplitude cyclic loading was studied in welded stiffened steel plates. The residual stresses in the stiffened plates were measured using the neutron diffraction strain‐scanning technique. The neutron diffraction measurements indicated that, in general, the residual stresses were tensile near the welded stiffeners and compressive between the stiffeners and ahead of the starter notch tips. Fatigue testing indicated that the fatigue crack growth rates of the stiffened plates were, in general, lower than that of a corresponding unstiffened plate, especially near the notch tips, where compressive residual stresses existed. An analytical method, using Green's function, was developed to predict the fatigue crack growth rates. Reasonable accuracy was obtained.

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Analysis of crack propagation in welded stiffened panels

Cited by 43 publications

References 6 publications

Fatigue crack propagation into the residual stress field along and perpendicular to laser beam butt‐weld in aluminium alloy AA6056

Fatigue crack propagation into the residual stress field along and perpendicular to laser beam butt‐weld in aluminium alloy AA6056

Multiscale fatigue crack growth modelling for welded stiffened panels

Experimental Investigation Into the Fatigue of Welded Stiffened 350WT Steel Plates Using Neutron Diffraction Method

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