Numerical investigation on stress concentration of corrosion pit

Cerit, Muhammet; Genel, Kenan; Ekşi, Seçil

doi:10.1016/j.engfailanal.2009.04.004

Cited by 253 publications

(98 citation statements)

References 12 publications

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“…Thus, the state of free surfaces in alloys 718 and 725 may affect the evolution of sub-surface microstructure and, ultimately, mechanical behaviors that depend on the integrity of γ and γ precipitates, such as initiation of planar bands. Stress concentration factors between 2 and 4 have been found at the tips of isolated surface notches [18] and pits [19,20] as well as for arrays of pits [21], supporting the view that dislocations are most likely to nucleate in their vicinity. Large pits have even been shown to nucleate cracks in steels [22].…”

supporting

confidence: 53%

Cutting Apart of γ″ Precipitates by Dislocations Emitted from Nanoscale Surface Notches in Ni-Base Alloy 725

Wang

Hanson

Gradečak

et al. 2013

Materials Research Letters

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supporting

confidence: 53%

Cutting Apart of γ″ Precipitates by Dislocations Emitted from Nanoscale Surface Notches in Ni-Base Alloy 725

Wang

Hanson

Gradečak

et al. 2013

Materials Research Letters

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“…Pitting associated with stress concentration has been the object of scientific studies, most of them are oriented to investigate the relationship between: the geometrical properties of one single pitting (semielliptical or hemispherical), and the stress concentration factors (Cerit et al 2009;Mu et al 2010;Zhao et al 2013). In a recent work has been investigated the stress concentration around perforations produced by corrosion in steel storage tanks (Godoy et al 2014); which points out that the irregular profiles of pitting can approach an elliptical perforation with two principal parameters: the number n of "grooves" or "waves" at the inner boundary of the perforation (cosine boundary and star-like boundary), and the deviation "d" of the cosine or star-like at the inner boundary.…”

Section: Discussionmentioning

confidence: 99%

Controlled Pre-Corrosion Attack and Ultrasonic Fatigue Endurance of Titanium Alloy Ti-6Al-4V

Tello

Almaraz

Tapia

et al. 2017

Lat. Am. j. solids struct.

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Ultrasonic fatigue tests were carried out on titanium alloy Ti-6Al-4V on the base material and the pre-corroded specimen to assess the pre-corrosion effect on the fatigue life of this alloy. The pre-corrosion was obtained by immersion of specimens in an acid solution: hydrochloric acid with 1.4 of pH during 8 and 16 minutes. All ultrasonic fatigue tests were performed following a predetermined sequence to attain the nominal applied load. Infrared images were taken at the neck section of specimens during ultrasonic fatigue testing, revealing that temperature is higher for the specimens with pre-corrosion and it increases with the time of pre-corrosion. It was observed that pits generated by pre-corrosion were associated with stress concentration, temperature increase and fatigue endurance decrease. Fracture surfaces were analyzed to determine the crack initiation and propagation and the stress intensity factor range threshold KTH was obtained for both: the pre-corroded and non pre-corroded specimens.

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“…7. The latter is a classical simplification used in finite element modelling of corrosion pits, see [9,16]. The sectional view at the middle plane of the pit reveals that the ex-service pit has a totally different strain pattern than the idealized pit, although both have identical boundary conditions.…”

Section: Finite Element Model Of Test Specimenmentioning

confidence: 99%

“…The first focuses on formulating improved analytical models for estimating stress intensity factors using linear elastic fracture mechanics, see [8][9][10]. Recent efforts have been devoted to enhance the pit model by considering more specific shape factors, accurate stress concentration factors using finite element simulations, and multi-step crack growth hypotheses [3,4].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Integrity of Steel Discs with Corrosion Pits

et al. 2018

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Abstract. Currently, prediction of crack initiation by corrosion pits is only possible by assuming regular geometrical shapes, such as semi-spheres or semi-ellipsoids. Moreover, typical fatigue life diagrams associate the crack initiation life with geometrical features, such as pit depth or aspect ratio, often leading to unsatisfactory correlations due to high pit shape variability and data scatter. In the context of blade-disc fixation in aero engine turbines, this limitation translates into highly conservative life estimations. Therefore, a new crack initiation predictor is formulated based on experimental testing and numerical analysis of 28 artificial corrosion pits. A low-cycle fatigue test campaign is conducted using three-point bending test specimens to simulate maximum takeoff operation conditions of the aero engine and the associated loading of the blade root designed as firtree. An artificial pit is located at the critical point of each test specimen, respectively. The prediction criterion is based on finite element analysis and is formulated as the lowest plastic strain of a plastic region with a certain volume in the corrosion pit. This reference volume is varied until an optimum correlation with experimental crack initiation life is obtained. The criterion shows a superior correlation with crack initiation life compared to pure geometrical parameters such as pit depth.

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Numerical investigation on stress concentration of corrosion pit

Cited by 253 publications

References 12 publications

Cutting Apart of γ″ Precipitates by Dislocations Emitted from Nanoscale Surface Notches in Ni-Base Alloy 725

Cutting Apart of γ″ Precipitates by Dislocations Emitted from Nanoscale Surface Notches in Ni-Base Alloy 725

Controlled Pre-Corrosion Attack and Ultrasonic Fatigue Endurance of Titanium Alloy Ti-6Al-4V

Mechanical Integrity of Steel Discs with Corrosion Pits

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