Estimation of the Stress Intensity Factor for 3D Cracked T – Joint

Pasca, Niculai; Marsavita, Liviu; Negru, Radu; Muntean, Sebastian

doi:10.1007/978-3-642-36691-8_41

Cited by 4 publications

(3 citation statements)

References 7 publications

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“…The failure under fatigue of the runner blades of the Francis turbines [11][12][13] is focused on the region of the weld seems located at the junction between blade-crown and bladeband because those regions present a higher risk to initiate cracks leading to the catastrophic failure under fatigue [14][15][16]. Several authors have investigated only the junctions between the blade-crown and the blade-band considering a simplified geometry of T-joint [17][18][19][20] because of the stress concentration is located in these critical regions. The stress distribution on the runner blades is determined using fluid-solid interaction (FSI) methodology [5,21].…”

Section: Introductionmentioning

confidence: 99%

Numerical assessment of stress concentration in Francis runner blade — crown/band junctions

2019

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The paper presents the results of numerical investigation for stress distribution near runner blade-crown/band junctions. Starting with the geometrical investigation of the geometries for a real turbine, different junction geometries were identified. Eight different junction geometries were numerically investigated in order to determine the stress distribution. The applied load for structural analysis was the pressure distribution, obtained from a Computational Fluid Dynamics analysis of the runner blade. The results of the stress distribution will allow to quantify the effect of different junction geometry on stress concentration and integrity of the runner.

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Section: Introductionmentioning

confidence: 99%

Numerical assessment of stress concentration in Francis runner blade — crown/band junctions

2019

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“…Chung et al [8] analyzed the effects of lack-ofpenetration crack size, weld leg size, and main plate thickness on mixed-mode stress intensity factors of loadcarrying fillet welded cruciform joints using the finite element method and the least-squares method, and the general formulae of modes I and II stress intensity factors obtained from numerical results were verified by experimental results. Pasca et al [9] determined the 3D stress intensity factors along the crack growth path of quarterelliptical corner cracks for T joint using FRANC3D in tension and bending loadings; crack growth paths were obtained from Paris' law based on the maximum tensile stress criterion. Pang et al [10] studied the 3D stress intensity factor and weld toe magnification factor of a semielliptical weld toe crack for T-butt joint using the three-dimensional extended finite element method.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the stress intensity factor of welded joints under prior corrosion and complex stress fields

Jie

Wei

2016

J. Mod. Transport.

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Taking cruciform welded joints under different corrosion degrees, together with 45°inclined angle and full penetration load-carrying fillet, as the research object, the stress intensity factor of a quarter-circular corner crack of welded joints is calculated based on FRANC3D with ABAQUS. Effects of different corrosion pit sizes, crack aspect ratios, and crack depths on stress intensity factor are analyzed. The results show that pit depth plays a major role in stress intensity factor, while the effect of pit radius is relatively small. The cracking modes of the surface and the deepest point are mode I, and mixed modes I and II, respectively. Effects of pit depths, crack aspect ratios, and crack depths on the stress intensity factor at the surface point are greater than at the deepest point.

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“…rotor-stator interaction, vortex, and so on), [1]. Therefore, several failures on machine elements of the hydropower units were reported in Romania after more than three decades in service operation, [2][3][4]. In these conditions, the reliability and maintenance of the hydropower equipments are the main elements in order to safety operate with minimum costs, [5].…”

Section: Introductionmentioning

confidence: 99%

Fatigue Behaviour of Stainless Steel Used for Turbine Runners

Negru

Marșavina

Muntean

et al. 2013

AEF

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Abstract. The key ingredient for any turbine runners design procedure and failure analysis is the material and its mechanical and fatigue properties. Starting from this observation, a series of static and dynamic tests were performed on the T10CuNiCr180 stainless steel after more than three decades of service. The fatigue tests were carried out under constant amplitude at a stress ratio of 0.1 and a frequency of 20 Hz. In the high cycle fatigue range, the S-N median curve was plotted and the fatigue limit for 3⋅10 6 cycles to failure was determined at 93.35 [MPa] expressed in stress amplitude. The casting and welding defects that were observed on fracture surfaces explained this lower fatigue limit. The fatigue crack growth tests were performed on compact tension specimens and a three-parameter model was used to plot the crack length versus number of cycles curves. In addition, the material constants from Paris' law were determined. Finally, the experimental results are compared against published data for another stainless steel.

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Estimation of the Stress Intensity Factor for 3D Cracked T – Joint

Cited by 4 publications

References 7 publications

Numerical assessment of stress concentration in Francis runner blade — crown/band junctions

Numerical assessment of stress concentration in Francis runner blade — crown/band junctions

Analysis of the stress intensity factor of welded joints under prior corrosion and complex stress fields

Fatigue Behaviour of Stainless Steel Used for Turbine Runners

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