scholarly journals Numerical Analysis Of The Harmfulness Of The Fatigue-Corrosion Defect In A Metal Pipe Under Internal Pressure

2020 ◽  
Vol 8 (10) ◽  
pp. 6940-6949
Keyword(s):  
Numerical Analysis ◽  
Internal Pressure ◽  
Corrosion Defect ◽  
Metal Pipe ◽  
Fatigue Corrosion

Investigation Into Applications of Local Failure Criterion for X70 Pipeline With Corrosion Defect

2018 ◽  
Author(s):  
Ji-Hee Moon ◽  
Nam-Su Huh ◽  
Ki-Seok Kim
Keyword(s):  
Internal Pressure ◽  
Failure Criterion ◽  
Large Scale ◽  
Ductile Failure ◽  
Limit Load ◽  
Local Failure ◽  
Ground Movement ◽  
Freezing And Thawing ◽  
Corrosion Defect ◽  
Longitudinal Length

In this paper, the local failure criterion using stress modified critical strain method based on annex B of API 579 is applied to evaluate the ductile failure of API X70 pipelines with a volumetric corrosion defect. Ductile failure is quantified in terms of strain, representing the tensile strain capacity (TSC) which is commonly used in strain-based assessment for fitness-for-service of pipelines installed in frozen area where large-scale ground movement can arise due to earthquakes, freezing and thawing. Based on the local failure criterion suggested for API X70 steel material, the TSCs of the corroded pipelines are evaluated by using the detailed finite element (FE) analyses. The effects of internal pressure and defect size (such as longitudinal length, circumferential width and depth in the direction of thickness) on TSC of pipelines subjected to axial displacement are systematically investigated. In addition, TSCs based on local failure criterion are compared with those based on net-section limit load. The TSCs from the present FE analyses for various defect geometries and internal pressure can be used to predict ductile failure of corroded pipelines and to build the framework for a strain-based assessment for in-service pipelines.

scholarly journals Cenosphere formation from heavy fuel oil: a numerical analysis accounting for the balance between porous shells and internal pressure

2016 ◽  
Vol 20 (1) ◽  
pp. 154-172 ◽  
Author(s):  
Vanteru M. Reddy ◽  
Mustafa M. Rahman ◽  
Appala N. Gandi ◽  
Ayman M. Elbaz ◽  
Robert A. Schrecengost ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Internal Pressure ◽  
Fuel Oil ◽  
Heavy Fuel Oil

Shakedown Study of Pipes With External Corrosion Under Cyclic Bending and Internal Pressure

2013 ◽  
Author(s):  
Marcelo Igor Lourenço ◽  
Theodoro A. Netto
Keyword(s):  
Numerical Analysis ◽  
Internal Pressure ◽  
Cyclic Plasticity ◽  
Cyclic Loads ◽  
Stress Concentrations ◽  
Cyclic Bending ◽  
Analysis Techniques ◽  
Process Plants ◽  
External Corrosion ◽  
Floating Platforms

Pipelines and rigid risers are susceptible to corrosion. This is also a concern for pipes onshore and on process plants of floating platforms. Once detected the corrosion defect on pipes under cyclic loads, the analysis carried out to decide on keeping the pipe in operation or repair/replace should consider that the defect may experience cyclic plasticity caused by stress concentrations and thickness reductions. In this condition, ratcheting can cause rapid failure. This paper presents a study combining experiments and different analysis techniques to evaluate the occurrence of ratcheting in pipes subjected to cyclic bending and internal pressure. Experiments with different defect geometries were carried out. Numerical analysis using incremental plasticity and shakedown procedures are presented and compared with the experiments.

Validity of Procedure for Plastic Collapse Assessment of a Local Thin Area Near Vessel and Nozzle Intersections Subjected to Internal Pressure and External Loadings

2015 ◽  
Author(s):  
Kenji Oyamada ◽  
Shinji Konosu ◽  
Tetsuji Miyashita ◽  
Takashi Ohno ◽  
Hideyuki Suzuki
Keyword(s):  
Numerical Analysis ◽  
Internal Pressure ◽  
Branch Pipe ◽  
Plastic Collapse ◽  
Collapse Assessment

There are numerous cases in which a volumetric flaw such as a local thin area (LTA) is found in pressure equipment such as vessels, piping, tanks, and so on. Sometimes it is found near vessel and nozzle intersection. A fitness for service (FFS) rule of such cases was desired, because plastic collapse assessment of LTA near vessel and nozzle intersection usually needed to conduct by numerical analysis such as FEA. Recently, an FFS assessment rule of plastic collapse assessment of LTA near vessel (run-pipe) and nozzle (branch pipe) intersection subjected to internal pressure and external loadings has been developed and proposed by one of authors of this paper. In this paper, the proposed plastic collapse assessment rule was verified with results of experiments and FEA for cylindrical vessels with an LTA near vessel and nozzle intersections subjected to internal pressure and external loadings.

Axial Compressive Loading Capacity of Pressurized Energy Pipeline With Corrosion Defects

2020 ◽  
Author(s):  
Bing Liu ◽  
Xiao Tan ◽  
Dinaer Bolati ◽  
Hang An ◽  
Jinxu Jiang
Keyword(s):  
Internal Pressure ◽  
Compressive Strain ◽  
Compressive Loading ◽  
Local Buckling ◽  
Simulation Method ◽  
Support Vector ◽  
Loading Capacity ◽  
Strain Capacity ◽  
Corrosion Defect ◽  
Corrosion Defects

Abstract Corrosion defects are dreadfully damaging to the stability of pipelines. Using the finite element (FE) simulation method, a model of API 5L X65 steel pipeline is established in this work to study its buckling behavior subjected to axial compressive loading. The local buckling state of the pipe at the ultimate axial compressive capacity was captured. Compared with the global compressive strain capacity (CSCglobal), the local compressive strain capacity (CSClocal) is more conservative. Extensive parametric analysis, including approximately 115 FE cases, was conducted to study the influence of the corrosion defect sizes and internal pressure on the corroded pipe’s compressive loading capacity (CLC) and CSC. Results show that the enlarged size of the corrosion defect decreases both the CLC and the CSC of the pipeline, but the CLC almost keeps unchanged as the length of corrosion defects increases. The CLC decreases with the increase of the length of corrosion defects when the length is less than 1.5Dt and greater than 0.7Dt. The CSC drops significantly until the length of the corrosion defect reached 1.8Dt. The deeper the corrosion defect, the smaller the CLC and the CSC. An increase in the width of corrosion defects tends to correspond to a decrease in the CLC and the CSC. With the increase of internal pressure, the CSC of the pipe gets greater while the CLC gets smaller. Based on the 115 FE results, a machine learning model based on support vector regression theory was developed to predict the pipe’s CSC. The regression coefficient between SVR predicted value and FEM actual value is 98.87%, which proves that the SVR model can predict the CSC with high accuracy and efficiency.

scholarly journals Numerical analysis of piping elbows for in-plane bending and internal pressure

2006 ◽  
Vol 44 (4) ◽  
pp. 393-398 ◽  
Author(s):  
E.M.M. Fonseca ◽  
F.J.M.Q. de Melo ◽  
C.A.M. Oliveira
Keyword(s):  
Numerical Analysis ◽  
Internal Pressure ◽  
Plane Bending

Reliability analysis of gas pipeline with corrosion defect based on finite element method

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yuan-Jian Yang ◽  
Guihua Wang ◽  
Qiuyang Zhong ◽  
Huan Zhang ◽  
Junjie He ◽  
...  
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Service Life ◽  
Reliability Analysis ◽  
Residual Life ◽  
Gas Pipeline ◽  
Stable Operation ◽  
Gas Pipelines ◽  
Content Type ◽  
Corrosion Defect

PurposeGas pipelines are facing serious risk because of the factors such as long service life, complex working condition and most importantly, corrosion. As one of the main failure reasons of gas pipeline, corrosion poses a great threat to its stable operation. Therefore, it is necessary to analyze the reliability of gas pipelines with corrosion defect. This paper uses the corresponding methods to predict the residual strength and residual life of pipelines.Design/methodology/approachIn this paper, ASME-B31G revised criteria and finite element numerical analysis software are used to analyze the reliability of a special dangerous section of a gas gathering pipeline, and the failure pressure and stress concentration of the pipeline under three failure criteria are obtained. Furthermore, combined with the predicted corrosion rate of the pipeline, the residual service life of the pipeline is calculated.FindingsThis paper verifies the feasibility of ASME-B31G revised criteria and finite element numerical analysis methods for reliability analysis of gas pipelines with corrosion defect. According to the calculation results, the maximum safe internal pressure of the pipeline is 9.53 Mpa, and the residual life of the pipeline under the current operating pressure is 38.41 years, meeting the requirements of safe and reliable operation.Originality/valueThe analysis methods and analysis results provide reference basis for the reliability analysis of corroded pipelines, which is of great practical engineering value for the safe and stable operation of natural gas pipelines.

Effect of Splitter Configurations on the Performance of a Sludge Pump

2019 ◽  
Author(s):  
Jeong-Min Jin ◽  
Hyo-Geun Ji ◽  
Youn-Jea Kim
Keyword(s):  
Numerical Analysis ◽  
Internal Pressure ◽  
Centrifugal Pump ◽  
Pressure Difference ◽  
Surface Friction ◽  
Working Fluid ◽  
Ansys Cfx ◽  
Crucial Component ◽  
Blade Shape ◽  
Pump Inlet

Abstract Sludge pump, a type of centrifugal pump, is widely used to transport high-density sludge. The pump uses the impeller to generate a pressure difference for transporting the working fluid. The impeller is a crucial component of the pump. The internal pressure becomes higher with an increasing number of impeller blades, and this in turn results in an increased head. However, the increase in the number of blades interferes with the pump inlet flow, resulting in an efficiency loss due to an increase of surface friction. Therefore, in this study, numerical analysis was performed using ANSYS CFX ver. 17.1 to elucidate the effect of splitter configurations on the performance of sludge pump. The numerical results were compared with the efficiency and head according to the change of the splitter length, as 35%, 60%, and 80% of the reference blade shape.

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