scholarly journals Crack growth analysis and remaining life prediction of dissimilar metal pipe weld joint with circumferential crack under cyclic loading

2020 ◽  
Vol 52 (12) ◽  
pp. 2949-2957
Author(s):  
A. Ramachandra Murthy ◽  
P. Gandhi ◽  
S. Vishnuvardhan ◽  
G. Sudharshan
Keyword(s):  
Cyclic Loading ◽  
Crack Growth ◽  
Weld Joint ◽  
Life Prediction ◽  
Growth Analysis ◽  
Remaining Life ◽  
Dissimilar Metal ◽  
Metal Pipe ◽  
Circumferential Crack

SCC Crack Growth Analysis for a Dissimilar Metal Weld Using Advanced FEA

2018 ◽  
Author(s):  
Takuya Ogawa ◽  
Masao Itatani ◽  
Takahiro Hayashi ◽  
Toshiyuki Saito
Keyword(s):  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Weld Joint ◽  
Growth Analysis ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Dissimilar Metal ◽  
Growth Properties ◽  
Dissimilar Metal Weld ◽  
Metal Weld

Management of plant service life is a key issue for improving the safety of light water reactors. Some incidents of primary water stress corrosion cracking (PWSCC) of pressurized water reactor (PWR) components, such as a primary loop piping/nozzle weld, and intergranular stress corrosion cracking (IGSCC) of boiling water reactor (BWR) components, such as a shroud support weld, have been reported in the past. When a crack is detected, crack growth analysis is required as part of the structural integrity assessment of the component with the crack. In Japan, the “Rules on Fitness-for-Service for Nuclear Power Plants” of the Japan Society of Mechanical Engineers (JSME FFS Code) describes the conventional methodology for analyzing crack growth. The methodology assumes a semi-elliptical crack shape and is based on crack growth calculation at only the deepest and surface points of the crack. However, the actual crack growth behavior is likely to be very different from that analyzed by the conventional methodology due to the complex distribution of residual stress and dependency of crack growth properties on the materials composing the weld joint, particularly in the case of cracks in a dissimilar metal weld. Recently, crack growth analysis techniques using finite element analysis (FEA) have been used to analyze crack growth behavior in more detail. In this study, a program code was developed for SCC crack growth analysis that consists of fracture mechanics analysis by “ABAQUS”, crack growth calculation and automatic remesh of the FE model by in-house code. Case studies of SCC crack growth analysis for a dissimilar metal weld were performed and the analysis results were compared with those obtained by the conventional methodology. As a result, it was confirmed that the conventional methodology provides a conservative estimation of crack growth behavior. It was also found that the difference in crack growth properties of individual materials composing the weld joint had a significant effect on the crack growth behavior, particularly on a dissimilar metal weld. Furthermore, the effect of the material anisotropy of the SCC crack growth rate for the weld metal on the crack growth behavior was investigated.

Development and Validation of Load-Interaction Based Models for Crack Growth Prediction

2014 ◽  
Author(s):  
Jiaxi Zhao ◽  
Weixing Chen ◽  
Sean Keane ◽  
Jenny Been ◽  
Greg Van Boven
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Life Prediction ◽  
Pressure Fluctuations ◽  
Remaining Life ◽  
The Past ◽  
Oil Pipelines ◽  
Rainflow Counting ◽  
Development And Validation

This investigation primarily focused on the validation of the software being developed for crack growth and remaining life prediction using SCADA data. A total of nine pressure spectra, four for oil pipelines and five for gas pipelines, have been collected and used as inputs for the software. It was found that these spectra could be categorized as the underload-, the meanload- and the overload-dominant spectra; each of them have shown different effects on crack growth: the underload spectra, typical of pressure fluctuations at the discharging sites, are most susceptible to crack growth because of load interactions between the minor pressure fluctuations and the unload cycles; while the overload spectra, often found at the suction site, have exhibited retarded crack growth due to the retardation effects caused by overloading. The relative severity of the load interactions in terms of crack growth rate for a given spectrum was quantified using a parameter termed as the Spectrum Factor. A Spectrum Factor greater than one indicates the enhanced crack growth rate by load interactions, such as the case where unloading is frequently present in the pressure spectra, while a Spectrum Factor lower than one may be associated with a retarded crack growth, which can be seen in pressure spectra with predominant overloading events. The predictions made by the models being developed were also compared with those made by the rainflow counting method. The software allows for the SCADA/pressure fluctuation data, in excel spreadsheet format, to be directly analyzed producing a projected remaining life of the pipeline based on the past pressure fluctuations and the assumed future pressure fluctuations.

scholarly journals Fatigue Life Prediction Based on Crack Growth Analysis Using an Equivalent Initial Flaw Size Model: Application to a Notched Geometry

2015 ◽  
Vol 114 ◽  
pp. 730-737 ◽  
Author(s):  
A.S.F. Alves ◽  
L.M.C.M.V. Sampayo ◽  
J.A.F.O. Correia ◽  
A.M.P. De Jesus ◽  
P.M.G.P. Moreira ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Crack Growth ◽  
Life Prediction ◽  
Growth Analysis ◽  
Flaw Size ◽  
Fatigue Life Prediction ◽  
Model Application ◽  
Size Model

Fatigue crack growth prediction model under variable amplitude loading conditions

2021 ◽  
pp. 105678952199873
Author(s):  
Menghan Li ◽  
Xin Liu ◽  
Zhenguo Li ◽  
Yingbo Zhang
Keyword(s):  
Crack Growth ◽  
Life Prediction ◽  
Stress Ratio ◽  
Crack Size ◽  
Model Parameters ◽  
Remaining Life ◽  
Variable Loading ◽  
Variable Amplitude Loading ◽  
Variable Amplitude ◽  
Crack Growth Model

Crack size prediction under variable amplitude loading is a very complex process, which is also important for life prediction in engineering. A crack growth model considering different stress ratio for fatigue remaining life prediction is proposed in this paper. The model utilizes stress ratio to describe the variable loading sequences, which makes the calculation greatly simplified. The rain-flow method is utilized to characterize the load sequence effects under variable amplitude loading. In addition, particle filter is utilized to estimate the model parameters describing the crack growth. Finally, case study indicates that the proposed approach is efficient in predicting crack growth and fatigue remaining life.

Fracture Analysis and Fatigue Remaining Life Prediction of Concrete Structural Components Accounting for Tension Softening and Size Effects

2010 ◽  
Vol 452-453 ◽  
pp. 649-652
Author(s):  
A. Rama Chandra Murthy ◽  
G.S. Palani ◽  
Nagesh R. Iyer
Keyword(s):  
Size Effect ◽  
Crack Growth ◽  
Size Effects ◽  
Life Prediction ◽  
Fracture Analysis ◽  
Remaining Life ◽  
Structural Components ◽  
Element Analysis ◽  
Paris Law ◽  
Tension Softening

This paper presents methodologies for fracture analysis and fatigue remaining life prediction of concrete structural components with and without accounting for tension softening and size effects. Stress intensity factor (SIF) is computed by conducting finite element analysis (FEA) and compared with that obtained by using analytical approach. The domain integral method has been used to calculate the strain energy release rate (SERR) and SIF by post-processing the FEA results. Nonlinear fracture mechanics principles (NLFM) have been used for crack growth analysis and remaining life prediction. Details of size effect in the computation of SIF and remaining life prediction have been presented. Size effect has been accounted for by modifying the Paris law, leading to size adjusted Paris law. Numerical studies have been conducted for fracture analysis, crack growth studies and remaining life prediction. The predicted remaining life values with the combination of tension softening & size effects are in close agreement with the corresponding experimental values available in the literature.

scholarly journals Prediction on Remaining Life of a V-Notched Beam by Measured Modal Frequency

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Wenguang Liu ◽  
Mark E. Barkey
Keyword(s):  
Cyclic Loading ◽  
Crack Growth ◽  
Cantilever Beam ◽  
Crack Depth ◽  
Growth Characteristic ◽  
Prediction Method ◽  
Remaining Life ◽  
Monitoring Method ◽  
Modal Frequency ◽  
Set Up

A prediction method for the remaining life of a V-notched beam using measured modal frequencies is proposed in this article. The main purpose is to provide a new monitoring method of crack growth for a cantilever beam. At first, the fatigue crack growth characteristic and the change law of modal frequencies of a V-notched cantilever beam under cyclic loading were studied by experiments. Subsequently, the relation of modal frequencies and crack growth were analyzed. Thereafter, the decrease ratio of the first modal frequency was employed to reflect the crack damage so as to set up the relation of the modal frequency and the crack damage, and the evolution model between the crack damage and the cyclic loading numbers were set up. A prediction method for crack growth life was proposed for a cantilever beam based on the decrease ratio of the first modal frequency in the end. The remaining life of a V-notched cantilever beam can be obtained using the proposed method with a given endured loading cycles and the corresponding measured modal frequency. Results indicate that the remaining fatigue life of the V-notched cantilever beam is related to the decrease ratio of the modal frequency, and the predicted remaining life is in good agreement with the measured remaining life as the crack depth extends to a certain value.

A Sensitivity Study: Effects of Toughness Values on Fatigue Crack Growth Analysis of Just-Survived Flaws Following a Pressure Test

2018 ◽  
Author(s):  
Matt Ellinger ◽  
Andy Lutz ◽  
Tom Bubenik ◽  
Tara McMahan
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Analysis ◽  
Hazardous Materials ◽  
Sensitivity Study ◽  
Remaining Life ◽  
Pressure Test ◽  
Life Values ◽  
Growth Analyses

The Pipeline and Hazardous Materials Safety Administration (PHMSA) issued a Notice of Proposed Rulemaking (NPRM)1 on April 8, 2016 that is expected to have an impact on the pipeline industry’s approach to crack growth analyses. Specifically, the NPRM defines values for pipe toughness that should be used in analyzing crack anomalies that are subjected to fatigue growth for instances in which known or measured pipe toughness values are not available. Pipeline Operators conduct these types of analyses to derive remaining life values which can in turn be utilized to establish pipeline integrity reassessment intervals. Thus, the impacts of this NPRM are felt by all pipeline operators who own assets in which cracking is considered a threat. The goal of this paper is to quantify the effects of using the NPRM defined toughness values in pressure test assessments for scenarios where pipe toughness values are unavailable.

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