Revisiting ASME Strain-Based Dent Evaluation Criterion

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Abu Naim Md Rafi ◽  
Sreekanta Das ◽  
Hossein Ghaednia ◽  
Jorge Silva ◽  
Richard Kania ◽  
...  
Keyword(s):  
Laboratory Tests ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Pipe Wall ◽  
Effective Strain ◽  
Evaluation Criterion ◽  
Lateral Loads ◽  
Finite Element Analyses ◽  
Cyclic Pressure ◽  
Long Run

Oil and gas transmission pipelines can be subjected to concentrated lateral loads and as a result, a dent can form. A dent is a localized defect in the pipe wall in the form of a permanent inward plastic deformation. This kind of defect is a matter of serious concern for the pipeline operator since a rupture or a leak may occur. Dent may not pose an immediate threat to the structural integrity of a pipeline. However, it can possibly hinder the operational and inline inspection activities. In the long run, it can cause a leak or rupture in the pipeline under sustained or cyclic pressure load. Hence, AMSE B31.8 recommends a strain-based criterion for the assessment of dents. This strain-based criterion was developed based on several assumptions. This study was undertaken using full-scale laboratory tests and finite element analyses to review and revisit the ASME strain-based dent evaluation criterion and its assumptions. It was found that some of these assumptions are incorrect, and hence, this dent evaluation criterion can lead to inaccurate estimations of critical (effective) strain values in dents, which in turn can lead to inaccurate assessments of the dents.

Behavior of X60 Line Pipe Subjected to Axial and Lateral Deformations

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Navid Nazemi ◽  
Sreekanta Das
Keyword(s):  
Laboratory Tests ◽  
Structural Integrity ◽  
Pipe Wall ◽  
Lateral Load ◽  
Test Method ◽  
Line Pipe ◽  
Test Setup ◽  
Steel Pipes ◽  
Sustained Loads ◽  
The University

Buried pipelines may be subjected to various complicated combinations of forces and deformations. This may result in localized curvature, strains, and associated deformations in the pipe wall. As a result, wrinkle may form. The wrinkled pipeline may then develop a rupture in the pipe wall and lose its structural integrity if it is subjected to further sustained loads or deformations. Recently, laboratory tests on NPS6 steel pipes were undertaken at the University of Windsor to study the wrinkling and post-wrinkling behaviors of this NPS6 pipe when subjected to lateral load in addition to internal pressure and axial load. Four full-scale laboratory tests were conducted, and it was found that the application of lateral load on wrinkled pipe produces a wrinkle shape similar to that occurred in a field NPS10 line pipe. Complex test setup was designed and built for successful loading and completion of these tests. This paper makes a detailed discussion on the test setup, test method, loading and boundary conditions, instruments used, and test results obtained from this study.

Development of a Smart Pipe Inspection Gauge for Detection of Pipeline Defects

2015 ◽  
Author(s):  
Oluwafemi Ayodeji Olugboji ◽  
Adinoyi Abdulmajeed Sadiq ◽  
Oluwafemi Olorunsaiye ◽  
David Omeiza Peters ◽  
Babatunde Ayobami Ajayi
Keyword(s):  
Laboratory Tests ◽  
Oil And Gas ◽  
Pipe Wall ◽  
Low Cost ◽  
Cost Effective ◽  
Wireless Transmission ◽  
Inspection System ◽  
Test Bed ◽  
Pipe Inspection ◽  
Pipeline Inspection

Pipeline defects and oil leakages pose an enormous challenge especially in the oil and gas industries, hence, the need for an effective and economical pipeline inspection system. This work focused on the development of a cost effective In-Line-Inspection tool called a smart pipe inspection gauge (PIG). A Test bed was designed and developed to simulate the impulses experienced by the PIG as it moved along the pipeline. The electronics and sensors embedded in the smart PIG were designed to detect vibrations as it moved along the pipe wall and allowed for the wireless transmission of data collected by the PIG system. The results obtained from the laboratory tests revealed dramatic changes in the vibrational intensity experienced by the smart PIG at various intervals. This validates the use of off-the-shelf sensing equipment with a low cost assembly to detect defects in pipelines.

Effect of Geometry, Material, and Pressure Variability on Strain and Stress Fields in Dented Pipelines Under Static and Cyclic Pressure Loading Using Probabilistic Analysis

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Husain M. Al-Muslim ◽  
Abul Fazal M. Arif
Keyword(s):  
Probabilistic Analysis ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Deterministic Model ◽  
Mechanical Damage ◽  
Statistical Distribution ◽  
Stress Fields ◽  
Pressure Loading ◽  
Cyclic Pressure ◽  
Pipe Geometry

Mechanical damage in transportation pipelines is a threat to their structural integrity. Failure in oil and gas pipelines is catastrophic as it leads to personal fatalities, injuries, property damage, loss of production, and environmental pollution. Therefore, this issue is of extreme importance to pipeline operators, government and regulatory agencies, and local communities. As mechanical damage can occur during the course of pipeline life due to many reasons, appropriate tools and procedures for assessment of severity is necessary. There are many parameters that affect the severity of the mechanical damage related to the pipe geometry and material properties, the defect geometry and boundary conditions, and the pipe state of strain and stress. The main objective of this paper is to investigate the effect of geometry, material, and pressure variability on strain and stress fields in dented pipelines under static and cyclic pressure loading using probabilistic analysis. Most of the published literature focuses on the strain at the maximum depth for evaluation, which is not always sufficient to evaluate the severity of a certain case. The validation and calibration of the base deterministic model was based on full-instrumented full-scale tests conducted by Pipeline Research Council International as part of their active program to fully characterize mechanical damage. A total of 100 cases randomly generated using Monte Carlo simulation are analyzed in the probabilistic model. The statistical distribution of output parameters and correlation between output and input variables is presented. Moreover, regression analysis is conducted to derive mathematical formulas of the output variables in terms of practically measured variables. The results can be used directly into strain based assessment. Moreover, they can be coupled with fracture mechanics to assess cracks for which the state of stress must be known in the location of crack tip, not necessarily found in the dent peak. Furthermore, probabilities derived from the statistical distribution can be used in risk assessment.

Effect of Geometry, Material and Pressure Variability on Strain and Stress Fields in Dented Pipelines Under Static and Cyclic Pressure Loading Using Probability Analysis

2010 ◽  
Author(s):  
Husain Mohammed Al-Muslim ◽  
Abul Fazal M. Arif
Keyword(s):  
Structural Integrity ◽  
Oil And Gas ◽  
Deterministic Model ◽  
Mechanical Damage ◽  
Statistical Distribution ◽  
Stress Fields ◽  
Pressure Loading ◽  
Cyclic Pressure ◽  
Mathematical Formulas ◽  
Pipe Geometry

Mechanical damage in transportation pipelines is a threat to its structural integrity. Failure in oil and gas pipelines is catastrophic as it leads to personal fatalities, injuries, property damage, loss of production and environmental pollution. Therefore, this issue is of extreme importance to Pipeline Operators, Government and Regulatory Agencies, and local Communities. As mechanical damage can occur during the course of pipeline life due to many reasons, appropriate tools and procedures for assessment of severity is necessary. There are many parameters that affect the severity of the mechanical damage related to the pipe geometry and material properties, the defect geometry and boundary conditions, and the pipe state of strain and stress. The main objective of this paper is to investigate the effect of geometry, material and pressure variability on strain and stress fields in dented pipelines under static and cyclic pressure loading using probabilistic analysis. Most of the published literate focuses on the strain at the maximum depth for evaluation which is not always sufficient to evaluate the severity of a certain case. The validation and calibration of the base deterministic model was based on full-instrumented full-scale tests conducted by Pipeline Research Council International as part of their active program to fully characterize mechanical damage. A total of 100 cases randomly generated using Monte Carlo simulations are analyzed in the probabilistic model. The statistical distribution of output parameters and correlation between output and input variables is presented. Moreover, regression analysis is conducted to derive mathematical formulas of the output variables in terms of practically measured variables. The results can be used directly into strain based design approach. Moreover, they can be coupled with fracture mechanics to assess cracks, for which the state of stress must be known in the location of crack tip, not necessarily found in the dent peak. Furthermore, probabilities derived from the statistical distribution can be used in risk assessment.

scholarly journals Mechanical Behavior of Steel Pipes With Local Wall Distortions Under Cyclic Loading

2012 ◽  
Author(s):  
Aglaia E. Pournara ◽  
Spyros A. Karamanos
Keyword(s):  
Cyclic Loading ◽  
Large Scale ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Pipe Wall ◽  
Local Stress ◽  
Local Strain ◽  
Design Guidelines ◽  
Repeated Loading ◽  
Steel Pipes

Evaluating the severity of pipe wall distortions is a crucial step towards safeguarding the structural integrity of aging hydrocarbon pipeline infrastructure. The present research refers to the remaining life of oil and gas transmission steel pipelines with local wall distortions (i.e. dents and buckles) under repeated loading. The research described in this paper constitutes the first part of a large numerical/experimental research project, aimed at developing methodologies and relevant design guidelines towards assessing and repairing structural pipeline damages in the form of local wall distortions. The paper describes numerical research aimed at investigating the residual structural integrity of smooth dented and buckled steel pipes, with respect to repeated loading that causes fatigue, with the purpose of designing large-scale experiments. Finite element models are developed to simulate the formation of dents and buckles on the pipe wall at various sizes (depths). The deformed steel pipes are further subjected to cyclic pressure or cyclic bending loading in order to estimate the remaining fatigue life of the deformed pipe. The local stress and strain variations due to cyclic loading application are calculated numerically at the deformed area of the pipe wall. In addition, the local strain variations are expressed in terms of strain concentration factors (SNCF) at the critical region of the pipe.

Behavior of NPS30 Pipe Subject to Denting Load

2014 ◽  
Author(s):  
Hossein Ghaednia ◽  
Kyle Gerard ◽  
Sudip Bhattacharjee ◽  
Sreekanta Das
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Three Dimensional ◽  
Petroleum Products ◽  
Lateral Loads ◽  
Element Analysis ◽  
Engineering Research ◽  
Three Dimensional Finite Element

Pipeline is the common mode for transporting oil, gas, and various petroleum products. Structural integrity of oil and gas transmission pipelines is often threatened by external interferences such as concentrated lateral loads and as a result, a failure of the pipeline may occur due to “mechanical damages”. Sometime, this load may not cause immediate rupture of pipes; rather form a dent which can reduce the pressure capacity of the pipeline. A dent is a localized defect in the pipe wall in the form of a permanent inward plastic deformation. This kind of defect is a matter of serious concern for the pipeline operator since a rupture or a leak may occur. Accordingly, an extensive experimental study is currently underway at the Centre for Engineering Research in Pipelines (CERP), University of Windsor on 30 inch (762 mm) diameter and X70 grade pipes with D/t of 90. The aim of this research is to examine the influence of various parameters such as dent shape and service pressure on strain distributions of dented pipe. Also, three-dimensional finite element models were developed and validated for determining strains underneath the indenter. The load-deformation behavior of pipes subject to this type of lateral denting load obtained from experimental study and finite element analysis is discussed in this paper. In addition, distributions of important strains in and around the dent obtained from the study are also discussed.

Influence of the Deformation Method on the Microstructure Changes in AZ31 Magnesium Alloy Round Rods Obtained by the Rolling Process

2016 ◽  
Vol 716 ◽  
pp. 864-870
Author(s):  
Andrzej Stefanik ◽  
Piotr Szota ◽  
Sebastian Mróz ◽  
Teresa Bajor ◽  
Sonia Boczkal
Keyword(s):  
Magnesium Alloy ◽  
Numerical Modelling ◽  
Rolling Mill ◽  
Laboratory Tests ◽  
Effective Strain ◽  
Rolling Process ◽  
Az31 Magnesium Alloy ◽  
Deformation Method ◽  
Microstructure Changes ◽  
Skew Rolling

This paper presents the research results of the microstructure changes of the round rods of AZ31 magnesium alloy in the hot rolling processes. The rolling was conducted in duo mill and a three-high skew rolling mill. Numerical modelling of the AZ31 magnesium alloy round rods rolling process was conducted using a computer program Forge 2011®. The verification of the results of numerical modelling was carried out during laboratory tests in a two-high rolling mill D150 and a three-high skew rolling mill RSP 40/14. Distributions of the total effective strain and temperature during AZ31 rods rolling process were determined on the basis of the theoretical analysis. Microstructure and texture changes during both analysed processes were studied.

Structural Integrity System Based on an Object-Oriented Activity- and Product Model

1993 ◽  
Author(s):  
Morten Lovstad ◽  
Tor G. Syvertsen
Keyword(s):  
Computational Models ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Physical Structure ◽  
Gas Production ◽  
Structural Safety ◽  
Actual State ◽  
Product Model ◽  
The North ◽  
Analysis Models

Abstract Huge steel or reinforced concrete structures in deep waters support the installations for oil and gas production in the North Sea. Steady operations in a hostile environment require that structural safety and integrity is maintained. For rapid evaluation and assessment of structural integrity in case of modifications or urgency situations, Structural Integrity Systems are established, comprising computational models and structural analysis programs. A major problem for structural assessment at short notice is to keep the analysis models updated and consistent with the actual state of the physical structure and the loadings. This paper proposes a layered approach for model integration, which enable maintenance of the models at a high level, from which detailed analysis models are derived in a consistent manner.

scholarly journals Integrity Management of Marine Structures; With Emphasis on Design for Structural Robustness

2018 ◽  
Author(s):  
Torgeir Moan
Keyword(s):  
Structural Damage ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Offshore Structures ◽  
Design Standards ◽  
Limit States ◽  
Fabrication Errors ◽  
Integrity Management ◽  
Operational Errors ◽  
And Control

Based on relevant accident experiences with oil and gas platforms, a brief overview of structural integrity management of offshore structures is given; including an account of adequate design criteria, inspection, repair and maintenance as well as quality assurance and control of the engineering processes. The focus is on developing research based design standards for Accidental Collapse Limit States to ensure robustness or damage tolerance in view damage caused by accidental loads due to operational errors and to some extent abnormal structural damage due to fabrication errors. Moreover, it is suggested to provide robustness in cases where the structural performance is sensitive to uncertain parameters. The use of risk assessment to aid decisions in lieu of uncertainties affecting the performance of novel and existing offshore structures, is briefly addressed.

Theorical Analysis of Leakage in High Pressure Pipe Using Acoustic Emission Method

2012 ◽  
Vol 445 ◽  
pp. 917-922 ◽  
Author(s):  
Saman Davoodi ◽  
Amir Mostafapour
Keyword(s):  
High Pressure ◽  
Acoustic Emission ◽  
Degrees Of Freedom ◽  
Oil And Gas ◽  
Pipe Wall ◽  
Leak Detection ◽  
Stress Waves ◽  
Motion Equation ◽  
Non Linear ◽  
Acoustic Emission Test

Leak detection is one of the most important problems in the oil and gas pipelines. Where it can lead to financial losses, severe human and environmental impacts. Acoustic emission test is a new technique for leak detection. Leakage in high pressure pipes creates stress waves resulting from localized loss of energy. Stress waves are transmitted through the pipe wall which will be recorded by using acoustic sensor or accelerometer installed on the pipe wall. Knowledge of how the pipe wall vibrates by acoustic emission resulting from leakage is a key parameter for leak detection and location. In this paper, modeling of pipe vibration caused by acoustic emission generated by escaping of fluid has been done. Donnells non linear theory for cylindrical shell is used to deriving of motion equation and simply supported boundary condition is considered. By using Galerkin method, the motion equation has been solved and a system of non linear equations with 6 degrees of freedom is obtained. To solve these equations, ODE tool of MATLAB software and Rung-Kuta numerical method is used and pipe wall radial displacement is obtained. For verification of this theory, acoustic emission test with continues leak source has been done. Vibration of wall pipe was recorded by using acoustic emission sensors. For better analysis, Fast Fourier Transform (FFT) was taken from theoretical and experimental results. By comparing the results, it is found that the range of frequencies which carried the most amount of energy is same which expresses the affectivity of the model.

Sign in / Sign up

Export Citation Format

Share Document