Statistical investigation of the weld joint efficiencies in the repaired WWER pressure vessel

Raslavičius, Laurencas; Bazaras, Žilvinas; Lukoševičius, Vaidas; Vilkauskas, Andrius; Česnavičius, Ramūnas

doi:10.1016/j.ijpvp.2020.104271

Cited by 9 publications

(4 citation statements)

References 10 publications

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“…x max x min (21) Figures 11 and 12 for steels 15Cr2MoVA and C45 compare the experimental lowcycle fatigue curves under strain-controlled loading of failure probability 1%, 50%, 99% with the calculated curves designed according to Equations(3), ( 5) and ( 6) by using the normalized mechanical characteristics determined according to Equation ( 21) and mechanical characteristics taken from reference documents [37], and the low-cycle fatigue curves defined using the safety factor 𝑛 𝑁 = 10 for cycles and 𝑛 𝑒 = 2 for strain as used in the field of mechanical engineering.…”

Section: K =mentioning

confidence: 99%

“…Daunys et al [18,19] investigated the dependence of low-cycle fatigue durability on the mechanical properties of steel welds in nuclear power plants. Timofeev et al [20] and Raslavičius et al [21] investigated the probabilistic low-cycle fatigue life and the dependence of low-cycle durability on the mechanical properties WWER-type reactor of the nuclear power plant made of steel 15Cr2MoVA and structural steel C45. Another study [22] involved the analysis of the mechanical reliability of magnesium alloys and systematic evaluation using the statistical Weibull analysis.…”

Section: Introductionmentioning

confidence: 99%

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Statistical Characterization of Strain-Controlled Low-Cycle Fatigue Behavior of Structural Steels and Aluminium Material

Bazaras

Lukoševičius

2022

Materials

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Probabilistic evaluation of the resistance to low-cycle deformation and failure of the critical components in the equipment used in the energy, engineering, metallurgy, chemical, shipbuilding, and other industries is of primary importance with the view towards their secure operation, in particular, given the high level of cyclic loading acting on the equipment during its operation. Until recently, systematic probabilistic evaluation has been generally applied to the results of statistical and fatigue investigations. Very few investigations applying this approach to the low-cycle domain. The present study aims to substantiate the use of probabilistic calculation in the low-cycle domain by systematic probabilistic evaluation of the diagrams of cyclic elastoplastic deformation and durability of the materials representing the major types of cyclic properties (hardening, softening, stabilization) and investigation of the correlation relationships between mechanical properties and cyclic deformation and failure parameters. The experimental methodology that includes the calculated design of the probabilistic fatigue curves is also developed and the curves are compared to the results of the experiment. Probabilistic values of mechanical characteristics were determined and calculated low-cycle fatigue curves corresponding to different failure probabilities, to assess them from the probabilistic perspective. A comparison of low-cycle fatigue curves has shown that the durability curves generated for some materials using analytical expressions are not accurate. According to the analysis of the relative values of experimental probabilities of low-cycle fatigue curves, the use of analytical expressions to build the curves can lead to a significant error. The results obtained allow for the revision of the load bearing capacity and life of the structural elements subjected to cyclic elastoplastic loading in view of the potential scattering of mechanical properties and resistance parameters to low-cycle deformation and failure. In addition, the results enable determination of the scatter tolerances, depending on the criticality of the part or structure.

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Section: K =mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Statistical Characterization of Strain-Controlled Low-Cycle Fatigue Behavior of Structural Steels and Aluminium Material

Bazaras

Lukoševičius

2022

Materials

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“…Xiang et al [8] proposed a general probabilistic life prediction methodology for accurate and efficient fatigue prognosis, which is based on the inverse first-order reliability method (IFORM) to evaluate the fatigue life at an arbitrary reliability level. Bazaras et al [9] and Raslavičius et al [10] investigated the low-cycle durability of nuclear power plants' WWER (Water-Water Energetic Reactor) steels 22k and 15Cr2MoVA. Zhu et al [11] developed a probabilistic methodology for low-cycle fatigue life prediction using an energy-based damage parameter under Bayes' theorem.…”

Section: Introductionmentioning

confidence: 99%

Probability Assessment of the Mechanical and Low-Cycle Properties of Structural Steels and Aluminium

Bazaras

Lukoševičius

Vilkauskas

et al. 2021

Metals

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Key mechanical properties used in low-cycle strength and durability calculations are the strength (proportional limit stress, σpr; relative yield strength, σ0.2; and ultimate tensile stress, σu) and strain properties (proportional limit strain, epr; percent area reduction, ψ; and percent area reduction at failure, ψu). When selecting the key mechanical properties provided in the specifications, an error may be made due to the failure to account for a series of random factors that determine the distribution of properties. The majority of research papers dealing with statistical descriptions of the low-cycle strain properties do not look deeper into the distribution of mechanical properties and the diagram parameters of strain characteristics. This paper provides a description of the distribution patterns of mechanical properties, statistical parameters, and low-cycle fatigue curves. Log-normal distribution generated the lowest values for the coefficient of variation of one of the key statistical indicators, suggesting that log-normal distribution is superior to normal or Weibull distribution in this respect. The distribution of low-cycle strain parameters exceeded the distribution of mechanical properties considerably. Minimum coefficients of variation of the parameters were generated at normal distribution. The statistical analysis showed the lower distribution of the durability parameters compared to the distribution of parameters of the strain diagrams. The findings of the paper enable a revision of the durability and life of the structural elements of in-service facilities subject to elastoplastic loading by assessing the distribution of mechanical characteristics and low-cycle strain parameters as well as the permissible distribution limits.

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“…Failures that occur are signs of shortcomings in the design, production, and maintenance methods used for a large number of objects. Determining or reviewing the service life of potentially hazardous objects designed or already in service requires the assurance of the strength of each element by making full use of the properties of the material [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Assessment of the Durability of Threaded Joints

et al. 2021

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The article deals with the determination of the resistance to cyclic loading of the threaded joints of pressure vessels and defective elements according to the failure mechanics criteria. Theoretical and experimental studies do not provide a sufficient basis for the existing calculation methods for the cyclic strength of the threaded joints of pressure vessels. The short crack kinetics in the threaded joints, a shakedown in one of the joint elements of pressure vessels, i.e., in the bolt or stud, has not been studied sufficiently. The calculation methods designed and improved within the study were based on theoretical and experimental investigations and were simplified for convenient application to engineering practice. The findings could be used to investigate the shakedown of studs of a different cross-section with an initiating and propagating crack. Value: the developed model for the assessment of durability of the threaded joints covers the patterns of resistance to cyclic failure (limit states: crack initiation, propagation, final failure) and shakedown (limit states: progressive shape change and plastic failure). Analysis-based solutions of plastic failure conditions and progressive shape change were accurate (the result was reached using a two-sided approach; the solutions were obtained in view of the parameters of the cyclic failure process in the stud (bolt) and based on experimental investigations of the threaded joints).

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Statistical investigation of the weld joint efficiencies in the repaired WWER pressure vessel

Cited by 9 publications

References 10 publications

Statistical Characterization of Strain-Controlled Low-Cycle Fatigue Behavior of Structural Steels and Aluminium Material

Statistical Characterization of Strain-Controlled Low-Cycle Fatigue Behavior of Structural Steels and Aluminium Material

Probability Assessment of the Mechanical and Low-Cycle Properties of Structural Steels and Aluminium

Assessment of the Durability of Threaded Joints

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