The Evaluation of Failure Pressure for Corrosion Defects Within Girth or Seam Weld in Transmission Pipelines

2004 ◽  
Author(s):  
Young-pyo Kim ◽  
Woo-sik Kim ◽  
Young-kwang Lee ◽  
Kyu-hwan Oh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Limit Load ◽  
The Body ◽  
Element Analysis ◽  
Burst Test ◽  
Corrosion Defect ◽  
Seam Weld ◽  
Failure Assessment ◽  
Corrosion Defects

The failure assessment for corroded pipeline has been considered with the burst test and the finite element analysis. The burst tests were conducted on 762mm diameter, 17.5mm wall thickness and API 5L X65 pipe that contained specially manufactured rectangular corrosion defect. The failure pressures for corroded pipeline have been measured by burst testing and classified with respect to corrosion sizes and corroded regions — the body, the girth weld and the seam weld of pipe. Finite element analysis was carried out to derive failure criteria of corrosion defect within the body, the girth weld and the seam weld of the pipe. A series of finite element analyses were performed to obtain a limit load solution for corrosion defects on the basis of burst test. As a result, the criteria for failure assessment of corrosion defect within the body, the girth weld and the seam weld of API 5L X65 gas pipeline were proposed.

Finite Element Analysis of Complex Corrosion Defects

2002 ◽  
Author(s):  
Duane S. Cronin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Burst Pressure ◽  
Uniaxial Tensile ◽  
Element Analysis ◽  
Internal Corrosion ◽  
Corrosion Defect ◽  
Elastic Plastic ◽  
Defect Assessment ◽  
Corrosion Defects

Aging gas and oil transmission pipeline infrastructure has led to the need for improved integrity assessment. Presently, external and internal corrosion defects are the leading cause of pipeline failure in Canada, and in many other countries around the world. The currently accepted defect assessment procedures have been shown to be conservative, with the degree of conservatism varying with the defect dimensions. To address this issue, a multi-level corrosion defect assessment procedure has been proposed. The assessment levels are organized in terms of increasing complexity; with three-dimensional elastic-plastic Finite Element Analysis (FEA) proposed as the highest level of assessment. This method requires the true stress-strain curve of the material, as determined from uniaxial tensile tests, and the corrosion defect geometry to assess the burst pressure of corrosion defects. The use of non-linear FEA to predict the failure pressure of real corrosion defects has been investigated using the results from 25 burst tests on pipe sections removed from service due to the presence of corrosion defects. It has been found that elastic-plastic FEA provides an accurate prediction of the burst pressure and failure location of complex-shaped corrosion defects. Although this approach requires detailed information regarding the corrosion geometry, it is appropriate for cases where an accurate burst pressure prediction is necessary.

Assessment Techniques Using the R6 Procedure: Investigation of Limit Load Approach for Pipe Branch Connections

2010 ◽  
Author(s):  
Peter A. Frost
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Surface Defect ◽  
Surface Defects ◽  
Local Limit ◽  
Limit Load ◽  
Elliptic Surface ◽  
Element Analysis ◽  
Limit Loads ◽  
Failure Assessment

The R6 Revision 4 Procedure ‘Assessment of the Integrity of Structures Containing Defects’, states that the use of the finite element ‘global’ limit load derived for pipe branch components can be non-conservative when used with the Option 1 and 2 failure assessment curves but that ‘local’ limit loads, based on the spread of plasticity through the pipe wall, should lead to conservative results. The current advice of R6 is based on separate studies by Fox and Connors of pipe branch components with fully extended surface defects. Their studies provide two distinct methods for calculating a suitably conservative local limit load. However, there is concern that these two methods may provide an overly conservative local limit load with therefore a less realistic prediction of defect tolerance. Furthermore, typical defectiveness is perhaps most commonly characterised as a semi-elliptic surface defect and it is therefore necessary to adapt both these methods in order to accommodate such defects. The purpose of this study was therefore to investigate local limit load approaches for pipe branch components with postulated semi-elliptic surface defects. A typical pipe branch component was chosen for assessment during this study, as part of a series of separate studies on a variety of pipe branch components. Local limit loads were calculated using two approaches. The first approach adapted the ‘Connors’ method by applying an adjustment to allow for the semi-elliptic surface defect; this is referred to as the ‘Modified Connors’ approach. The second approach used cracked body finite element analysis and evaluated the local limit load by consideration of the onset of plasticity at the crack ligament. The global limit load was also derived from the cracked body finite element analysis. Assessment points were developed using global and local limit loads, both obtained by cracked body finite element analysis, and also by using the ‘Modified Connors’ local limit load approach. R6 Option 3 failure assessment curves were produced for each limit load approach in order to investigate the extent of any non-conservatism in the Option 1 and 2 failure assessment curves with the chosen limit load approach.

Full Scale Burst Test and Finite Element Analysis on Corroded Gas Pipeline

2002 ◽  
Author(s):  
Woo-Sik Kim ◽  
Young-Pyo Kim ◽  
Young-Tai Kho ◽  
Jae-Boong Choi
Keyword(s):  
Finite Element ◽  
Limit Load ◽  
Failure Criteria ◽  
Finite Element Analyses ◽  
Gas Pipelines ◽  
Element Analysis ◽  
Burst Test ◽  
Element Simulation ◽  
X65 Steel ◽  
Corrosion Defects

Pipelines have the highest capacity and are the safest and least environmentally disruptive way for gas or oil transmission. Recently, failures due to corrosion defects became of major concern in maintaining pipeline integrity. A number of solutions have been developed for the assessment of remaining strength of corroded pipelines. However, these solutions are known to be dependent on material properties and pipeline geometries. In this paper, a Fitness-For-Purpose (FFP) type limit load solution for corroded gas pipelines made of X65 steel is proposed based on experimental results and finite element analyses. For this purpose, a series of burst tests with various types of corrosion defects was performed. Finite element simulation was carried out on burst test to derive failure criteria. And then, a series of finite element analyses were performed to obtain a limit load solution for a single corrosion defect on the basis of burst test simulation. As a result, an FFP type limit load solution for corroded X65 gas pipelines was proposed.

scholarly journals Effect of Ovality in Inlet Pigtail Pipe Bends Under Combined Internal Pressure and In-Plane Bending for Ni-Fe-Cr B407 Material

2017 ◽  
Vol 62 (3) ◽  
pp. 1881-1887
Author(s):  
P. Ramaswami ◽  
P. Senthil Velmurugan ◽  
R. Rajasekar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Limit Load ◽  
Outer Radius ◽  
Factor H ◽  
Geometrical Shape ◽  
Element Analysis ◽  
Pipe Bend ◽  
Plane Bending

Abstract The present paper makes an attempt to depict the effect of ovality in the inlet pigtail pipe bend of a reformer under combined internal pressure and in-plane bending. Finite element analysis (FEA) and experiments have been used. An incoloy Ni-Fe-Cr B407 alloy material was considered for study and assumed to be elastic-perfectly plastic in behavior. The design of pipe bend is based on ASME B31.3 standard and during manufacturing process, it is challenging to avoid thickening on the inner radius and thinning on the outer radius of pipe bend. This geometrical shape imperfection is known as ovality and its effect needs investigation which is considered for the study. The finite element analysis (ANSYS-workbench) results showed that ovality affects the load carrying capacity of the pipe bend and it was varying with bend factor (h). By data fitting of finite element results, an empirical formula for the limit load of inlet pigtail pipe bend with ovality has been proposed, which is validated by experiments.

Rigid-Plastic Finite Element Simulation of Cold Forging and Sheet Metal Forming by Eulerian Meshing Method

2014 ◽  
Vol 970 ◽  
pp. 177-184 ◽  
Author(s):  
Wen Chiet Cheong ◽  
Heng Keong Kam ◽  
Chan Chin Wang ◽  
Ying Pio Lim
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Large Deformation ◽  
Sheet Metal ◽  
Metal Forming ◽  
The Body ◽  
Cold Forging ◽  
Rigid Plastic ◽  
Element Analysis ◽  
Linear Solution

A computational technique of rigid-plastic finite element method by using the Eulerian meshing method was developed to deal with large deformation problem in metal forming by replacing the conventional way of applying complicated remeshing schemes when using the Lagrange’s elements. During metal forming process, a workpiece normally undergoes large deformation and causes severe distortion of elements in finite element analysis. The distorted element may lead to instability in numerical calculation and divergence of non-linear solution in finite element analysis. With Eulerian elements, the initial elements are generated to fix into a specified analytical region with particles implanted as markers to form the body of a workpiece. The particles are allowed to flow between the elements after each deformation step to show the deforming pattern of material. Four types of cold forging and sheet metal clinching were conducted to investigate the effectiveness of the presented method. The proposed method is found to be effective by comparing the results on dimension of the final product, material flow behaviour and punch load versus stroke obtained from simulation and experiment.

Capacity Analysis of PE Pipeline With Non-Planar Defect

2013 ◽  
Author(s):  
Weijie Jiang ◽  
Jianping Zhao ◽  
Dingyue Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Constitutive Model ◽  
Mechanical Performance ◽  
Orthogonal Design ◽  
Bending Moment ◽  
Limit Load ◽  
Capacity Analysis ◽  
Element Analysis ◽  
Load Factors

A tensile test of buried PE pipe is designed to test the mechanical performance. Then the constitutive model for the PE pipe can be established. The limit load of the PE pipe with local thinning defect can be studied with the method of combining the orthogonal design of experiment and finite element analysis. Then the factors of local thinning defect pipe limit load factors can be analyzed. The results show that the depth of the defect has a great effect on the limit load (internal pressure and bending moment) of PE pipe. The effects that the axial length of the defect and the circumferential length of the defect have on the limit load are not significant.

Finite Element Analysis of Buckling of Arteries With Aneurysms

2009 ◽  
Author(s):  
Avione Northcutt ◽  
Hai-Chao Han
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
The Body ◽  
Element Analysis ◽  
Arterial Tortuosity ◽  
Dangerous Condition ◽  
Cerebrovascular Symptoms

Tortuosity of arteries occurs when a normally straight artery starts to take on a twisted path. This is often referred to as tortuosity and kinking of arteries. This phenomenon occurs in arteries throughout the body including the aorta and cerebral [1, 2]. Arterial tortuosity is a potentially dangerous condition that can lead to cerebrovascular symptoms, ischemia, and stroke [3].

Finite Element Simulation for Forging Process Using Euler’s Fixed Meshing Method

2008 ◽  
Vol 575-578 ◽  
pp. 1139-1144 ◽  
Author(s):  
Chan Chin Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Large Deformation ◽  
The Body ◽  
Rigid Plastic ◽  
Element Analysis ◽  
Forging Process ◽  
Deformation Problem ◽  
Element Method

A simulator based on rigid-plastic finite element method is developed for simulating the plastic flow of material in forging processes. In the forging process likes backward extrusion, a workpiece normally undergoes large deformation around the tool corners that causes severe distortion of elements in finite element analysis. Since the distorted elements may induce instability of numerical calculation and divergence of nonlinear solution in finite element analysis, a computational technique of using the Euler’s fixed meshing method is proposed to deal with large deformation problem by replacing the conventional way of applying complicated remeshing schemes when using the Lagrange’s elements. With this method, the initial elements are generated to fix into a specified analytical region with particles implanted as markers to form the body of a workpiece. The particles are allowed to flow between the elements after each deformation step to show the deforming pattern of material. The proposed method is found to be effective in simulating complicated material flow inside die cavity which has many sharp edges, and also the extrusion of relatively slender parts like fins. In this paper, the formulation of rigid-plastic finite element method based on plasticity theory for slightly compressible material is introduced, and the advantages of the proposed method as compared to conventional one are discussed.

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