Fatigue studies on carbon steel piping materials and components: Indian PHWRs

Singh, Pavan Kumar; Bhasin, V.; Vaze, K.K.; Ghosh, Antara; Kushwaha, H. S.; Murthy, D. S. Ramachandra; Gandhi, P.; Sivaprasad, Sobha

doi:10.1016/j.nucengdes.2007.09.002

Cited by 14 publications

(12 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2 The reference for the distribution of Paris' constants by most of the papers addressing probabilistic FCG is the work of Virkler. The prior distribution and the coefficient of variation of the Paris' constants were adopted from the literature.…”

Section: Statistics Of Paris' Constantsmentioning

confidence: 99%

See 1 more Smart Citation

Fatigue crack growth prediction in nuclear piping using Markov chain Monte Carlo simulation

Rastogi

Ghosh

et al. 2016

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

In this paper, we present and demonstrate a methodology to improve probabilistic fatigue crack growth (FCG) predictions by using the concept of Bayesian updating using Markov chain Monte Carlo simulations. The methodology is demonstrated on a cracked pipe undergoing fatigue loading. Initial estimates of the FCG rate are made using the Paris law. The prior probability distributions of the Paris law parameters are taken from the tests on specimen made of the same material as that of pipe. Measured data on crack depth over number of loading cycles are used to update the prior distribution using the Markov chain Monte Carlo. The confidence interval on the predicted FCG rate is also estimated. In actual piping placed in a plant, the measured data can be considered equivalent to the data received from in‐service inspection. It is shown that the proposed methodology improves the fatigue life prediction. The number of observations used for updating is found to leave a significant effect on the accuracy of the updated prediction.

show abstract

Section: Statistics Of Paris' Constantsmentioning

confidence: 99%

“…2 The diameter of the pipe is 324 mm, and it has a partthrough wall circumferential crack on the external surface. 2 The diameter of the pipe is 324 mm, and it has a partthrough wall circumferential crack on the external surface.…”

Section: Introductionmentioning

confidence: 99%

Fatigue crack growth prediction in nuclear piping using Markov chain Monte Carlo simulation

Rastogi

Ghosh

et al. 2016

Fatigue Fract Eng Mat Struct

View full text Add to dashboard Cite

show abstract

“…Three pipes of 324 mm outer diameter and 21.5 mm thickness of the piping system have been used in the study 13 . Two pipes are made of SA333Gr.6 carbon steel base material and one of SA333Gr.6 carbon steel weld material.…”

Section: Materials Properties and Pipe Test Datamentioning

confidence: 99%

“…The constant amplitude loading with the stress ratio ( R ) of 0.1 and 0.5 had reportedly been followed during the test in different cases. In the analyses for the weld metal case of PBSC‐12‐4, same material properties, as of base material, are used, as no significant difference in crack growth properties is observed in the tested specimens made up of base and weld metals 13 …”

Section: Materials Properties and Pipe Test Datamentioning

confidence: 99%

See 1 more Smart Citation

Assessing the accuracy of fatigue life in surface-cracked straight pipes

Saxena

2011

Fatigue &Amp; Fracture of Engineering Materials &Amp; Structures

View full text Add to dashboard Cite

A B S T R A C T The demonstration of leak before brake (LBB) based on fracture mechanics requires information on the initial size of a defect, initiation of crack growth from the inherent defect and subsequent crack growth rates. In the present paper the prediction methodologies have been tested for three different full scale pipes geometry experimentally tested data. The prediction accuracy of two SIF solutions available in the literature has also been judged. The effect of fatigue crack closure and corrections needed in the numerical prediction methodology using FEM have also been included. The results showed that the FEM could fairly predict the fatigue crack initiation and crack growth life of full-scale piping components having a constant depth crack profile.Keywords crack growth; cracked pipes; fatigue loading; finite element analysis; stress intensity factor. I N T R O D U C T I O NFailure of piping components under normal operating conditions well below the allowable stress given by codes can often be due to flaws. Crack-like defects could develop at the manufacturing/installation stage or it could develop as a result of continued operation, with cyclic loading and material deterioration being the two major causes for defect initiation and propagation. 1 This necessitates detailed flaw evaluation of different piping components such as straight pipes, elbow and branch tees. In the primary heat transporting system of power plants, piping components are subjected to high stresses due to temperature fluctuations, vibration, etc. Based on the results of investigations of failures conducted by Nishida and his co-operating researchers, failures are generally caused directly or indirectly by fatigue. 2 Such failures show that conventional stress analysis is not sufficient to guarantee component integrity under operational condition. Design criteria for the prevention of fatigue failure have evolved from the concept of almost infinite life to the presentday fail-safe design philosophy. Therefore, fail-safe design criteria such as leak-before-break (LBB) based on fracture mechanics concepts are being adopted. An important consideration in this methodology is the selection of materials with high fracture toughness. This design criterion requires the demonstration of integrity of the piping Correspondence: S. Saxena. system by showing that unstable crack growth will not occur before a crack penetrates the wall thickness, nor will it occur for a through-wall leakage size flaw. The demonstration of LBB design criteria requires information on the size of initial defects, initiation of crack from the inherent defect and subsequent propagation rate of the initiated crack till the crack penetrates the wall thickness under fatigue loading. Thereafter, the crack will grow in the circumferential direction under cyclic loading till the acceptable leakage size flaw yields the detectable leakage rate. 3 Therefore, various tests are required for the determination of fatigue crack initiation, fatigue crack growth and fracture resi...

show abstract