Measuring Critical Strains in Dent Defect of Oil and Gas Pipes

2016 ◽  
Author(s):  
Jandark Oshana-Jajo ◽  
Jamshid Zohrehheydariha ◽  
Hossein Ghaednia ◽  
Sreekanta Das
Keyword(s):  
Laboratory Testing ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Economic Loss ◽  
Physical Contact ◽  
Environmental Damage ◽  
Element Analysis ◽  
Engineering Research ◽  
Critical Strains ◽  
Pipe Materials

Steel pipelines are exposed to harsh environmental, geotechnical and other conditions and hence, they can be damaged. The damage can threaten the structural integrity of the pipeline and can cause economic loss and environmental damage if a failure occurs. A common way for pipelines to be damaged is through physical contact, creating a structural imperfection, dent, wrinkle, crack, and/or other damages or defects. A dent disrupts the pipeline’s circularity causing increased strains in concentrated areas. A research program was established and carried out to study the strain concentration of dented pipes. The study was completed using full-scale laboratory testing and numerical analysis at the Centre for Engineering Research in Pipelines (CERP). This study included four lab tests on two different pipe materials (X70 and X56) and finite element analysis (FEA) based parametric study.

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.

Investigation of Strain-Based Failure Assessment Based on Reference Strain Method for Welded Pipes

2019 ◽  
Author(s):  
Jae Sung Lee ◽  
Myung Hyun Kim
Keyword(s):  
Reference Strain ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Effective Means ◽  
Equivalent Stress ◽  
Strain Curve ◽  
Evaluation Procedure ◽  
Element Analysis ◽  
Integrity Assessment ◽  
Strain Method

Abstract Pipelines are effective means to transport oil and gas. It is essential to maintain the safety of pipelines with the increasing demand for oil and gas resource. Welded pipelines may suffer damage such as cracks during installation and operation, and the consequence evaluation for such damage is very important. Engineering critical assessment (ECA) is the evaluation procedure for structures with flaws and has been widely applied for assessing the pipeline integrity. Although main standards of structural integrity assessment including BS 7910 are stress-based ECA, it is known to produce overly conservative results. In this regard, strain-based ECA has been recently developed. One of the methods for improving the accuracy of strain-based ECA is the reference strain method. However, only few researches with reference strain method applied to welded pipes are available. Therefore, in this study, a numerical analysis based on the strain-based ECA is performed for strength mismatched girth welded joints with a circumferentially oriented internal surface crack. Equivalent stress-strain curve in BS7910 is employed to reflect the strength mismatch effects in the reference strain. This paper compares the results from the reference strain method and finite element analysis: J-integral and reference strain. Strain capacity of the reference strain method with strength mismatch is also discussed against stress-based ECA.

Structural Strength Assessment of Dented Steel Tubular Members

2021 ◽  
Author(s):  
S. Saad-Eldeen ◽  
Mahmoud Helal ◽  
Elsayed Fathallah
Keyword(s):  
Residual Strength ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Geometrical Parameters ◽  
Element Analysis ◽  
Strength Assessment ◽  
Operational Conditions ◽  
Integrity Assessment ◽  
Modes Of Failure ◽  
Ultimate Load Carrying Capacity

Abstract Tubular members are widely used in oil and gas offshore production and drilling structures either fixed or mobile units. Due to complex operational conditions, the tubular members are subjected to both age and mechanical related damage, which in turn affect the ability of the structure to withstand the applied loads. This motivates the importance of investigating the behavior of tubular members considering the presence of dentation resulting from collision or falling objects and consequently assessing the residual strength of the damaged members accurately. A series of finite element analysis are performed to study the pre- and post-ultimate strength behavior of intact and locally dented un-stiffened steel tubular members subjected to four-point bending. The effects of dent geometrical parameters; length, width, depth, orientation, and location on the ultimate load carrying capacity are analyzed. The ratio between the diameters to the shell thickness is varied, where combined local and global initial imperfections are considered. Buckling and post collapse analysis as well as modes of failure are studied. Parametric diagrams for the ultimate residual strength as a function of dent geometry and the location of damage are also presented. Several concluding remarks are stated which benefit the structural integrity assessment of tubular steel members.

Mechanical Properties Characterization and Finite Element Analysis of Epoxy Grouts in Repairing Damaged Pipeline

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Lim Kar Sing ◽  
Nordin Yahaya ◽  
Alireza Valipour ◽  
Libriati Zardasti ◽  
Siti Nur Afifah Azraai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Flexural Behavior ◽  
Fe Model ◽  
Element Analysis ◽  
Structural Repair ◽  
Repair Mechanisms ◽  
Infill Material

Oil and gas pipelines are subjected to various types of deterioration and damage over long service years. These damaged pipes often experience loss of strength and structural integrity. Repair mechanisms have been developed in restoring the loading capacity of damaged pipelines, and composite repair systems have become popular over the past few years. The mechanical properties of the putty/grout are critical to their potential application as infill materials in structural repair. In this paper, the compression, tensile, and flexural behavior of four epoxy grouts was investigated through laboratory tests. The stiffness of the grouts for compression, tensile, and flexural was found to be 6 GPa to 18 GPa, 4 GPa to 15 GPa, and 4 GPa to 12 GPa, respectively. The ultimate strength for all grouts was found from 62 MPa to 87 MPa, 18 MPa to 38 MPa, and 34 MPa to 62 MPa under compression, tensile, and flexural tests, respectively. The behavior of all the tested grouts is discussed. A finite element (FE) model simulating a composite-repaired pipe was developed and compared with past studies. The FE results show a good correlation with experimental test with margin of error less than 10%. By replacing the infill properties in FE model to mimic the used of different infill material for the repair, it was found that about 4–8% increment in burst pressure can be achieved. This signifies that the role of infill material is not only limited to transferring the load, but it also has the potential to increase overall performance of composite-repaired pipe.

Out-of-Roundness in NPS30 X70 Pipes Subjected to Concentrated Lateral Load

2014 ◽  
Author(s):  
Hossein Ghaednia ◽  
Jamshid Zohrehheydariha ◽  
Sreekanta Das ◽  
Rick Wang ◽  
Richard Kania
Keyword(s):  
Structural Integrity ◽  
Oil And Gas ◽  
Impact Load ◽  
Test Procedure ◽  
Research Work ◽  
Mechanical Damage ◽  
Lateral Load ◽  
External Pressure ◽  
Concentrated Load ◽  
Engineering Research

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 load, impact load, and external pressure. These external interferences can cause ‘mechanical damage’ leading to structural failure in onshore and offshore linepipes. Lateral load is applied as a concentrated load on a small area of pipe segment and can cause local buckling, bend, dent, or out-of-roundness in the pipe. As an example, a concentrated load in buried onshore linepipe can occur if a segment of the linepipe rests on a narrow rock tip or even a narrow hard surface. Such concentrated lateral load may or may not cause immediate rupture or leak in the linepipe; however, it may produce out-of-roundness with or without a dent in the pipe cross section, which can be detrimental to the structural and/or operational integrity of the pipeline. Hence, the pipeline operator becomes concerned about the performance and safety of the linepipe if a pipe section is subject to a sustained concentrated load. A research work using full-scale tests and finite element method (FEM) was undertaken at the Centre for Engineering Research in Pipelines (CERP), University of Windsor to study the influence of various internal pressures and diameter-to-thickness ratios on the out-of-roundness of 30 in diameter (NPS 30) and X70 grade pipes with D/t of 90 when subjected to a stroke-controlled concentrated load. This paper discusses the test specimens, test setup, test procedure, test results, and FEM results obtained from this study.

Ovalization Defect in Energy Pipes Caused by Concentrated Load

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Hossein Ghaednia ◽  
Sreekanta Das
Keyword(s):  
Structural Integrity ◽  
Complex Loading ◽  
Outer Wall ◽  
Buried Pipelines ◽  
Element Analysis ◽  
Cross Sectional ◽  
Concentrated Load ◽  
Engineering Research ◽  
Steel Pipes ◽  
The University

Steel pipes are used to build pipelines that carry gas and oil across a country or a continent. The majority of onshore pipelines run underground; hence, they are called buried pipelines. These buried pipelines must endure external interferences and complex loading that result from geotechnical causes, aggressive environments, and operational requirements. Many segments of an underground pipeline may rest on rock tips and other localized hard surfaces, resulting in concentrated reaction load acting on small area of the outer wall of the operating pipeline. As a result, permanent inward deformations in the pipe wall, known as dent defect, can form. In addition, a resulting cross-sectional irregularity, known as an ovalization defect, can also occur. Pipe ovalization defects are a concern of pipeline operating companies, as the defect may challenge a pipeline's operation and/or structural integrity and safety. This research was completed by the Centre of Engineering Research in Pipelines located at the University of Windsor to examine the effects that rock tip shape, operating (internal) pressure, and a pipe's diameter-to-thickness ratio (D/t) have on an NPS30 X70-grade pipe's ovalization defect when it is subjected to such a concentrated load. This article discusses the lab-based full-scale examinations, finite element analysis (FEA) simulations, results, and discussions.

Tire Bead Overheating in Urban Buses and Trucks Using Drum Brake Systems

1998 ◽  
Vol 26 (1) ◽  
pp. 51-62
Author(s):  
A. L. A. Costa ◽  
M. Natalini ◽  
M. F. Inglese ◽  
O. A. M. Xavier
Keyword(s):  
Heat Transfer ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Energy ◽  
Structural Integrity ◽  
Experimental Temperature ◽  
Temperature Profiles ◽  
Element Analysis ◽  
Drum Brake ◽  
Fea Model

Abstract Because the structural integrity of brake systems and tires can be related to the temperature, this work proposes a transient heat transfer finite element analysis (FEA) model to study the overheating in drum brake systems used in trucks and urban buses. To understand the mechanics of overheating, some constructive variants have been modeled regarding the assemblage: brake, rims, and tires. The model simultaneously studies the thermal energy generated by brakes and tires and how the heat is transferred and dissipated by conduction, convection, and radiation. The simulated FEA data and the experimental temperature profiles measured with thermocouples have been compared giving good correlation.

scholarly journals Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

2015 ◽  
Vol 12 (19) ◽  
pp. 5871-5883 ◽  
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield
Keyword(s):  
Climate Change ◽  
Finite Element ◽  
Structural Integrity ◽  
Geometric Model ◽  
Algal Growth ◽  
Coralline Algae ◽  
Rocky Shores ◽  
Element Analysis ◽  
Scan Data ◽  
The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

scholarly journals Rapid Multi-Hybridisation FISH Screening for Balanced Porcine Reciprocal Translocations Suggests a Much Higher Abnormality Rate Than Previously Appreciated

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 250
Author(s):  
Rebecca E O’Connor ◽  
Lucas G Kiazim ◽  
Claudia C Rathje ◽  
Rebecca L Jennings ◽  
Darren K Griffin
Keyword(s):  
Semen Analysis ◽  
In Situ Hybridisation ◽  
Economic Loss ◽  
Environmental Damage ◽  
Fluorescence In Situ Hybridisation ◽  
Reciprocal Translocations ◽  
Chromosome Translocations ◽  
Farrowing Rate ◽  
Significant Economic Loss

With demand rising, pigs are the world’s leading source of meat protein; however significant economic loss and environmental damage can be incurred if boars used for artificial insemination (AI) are hypoprolific (sub-fertile). Growing evidence suggests that semen analysis is an unreliable tool for diagnosing hypoprolificacy, with litter size and farrowing rate being more applicable. Once such data are available, however, any affected boar will have been in service for some time, with significant financial and environmental losses incurred. Reciprocal translocations (RTs) are the leading cause of porcine hypoprolificacy, reportedly present in 0.47% of AI boars. Traditional standard karyotyping, however, relies on animal specific expertise and does not detect more subtle (cryptic) translocations. Previously, we reported development of a multiple hybridisation fluorescence in situ hybridisation (FISH) strategy; here, we report on its use in 1641 AI boars. A total of 15 different RTs were identified in 69 boars, with four further animals XX/XY chimeric. Therefore, 4.5% had a chromosome abnormality (4.2% with an RT), a 0.88% incidence. Revisiting cases with both karyotype and FISH information, we reanalysed captured images, asking whether the translocation was detectable by karyotyping alone. The results suggest that chromosome translocations in boars may be significantly under-reported, thereby highlighting the need for pre-emptive screening by this method before a boar enters a breeding programme.

scholarly journals Computational and experimental mechanical performance of a new everolimus-eluting stent purpose-built for left main interventions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Saurabhi Samant ◽  
Wei Wu ◽  
Shijia Zhao ◽  
Behram Khan ◽  
Mohammadali Sharzehee ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Mechanical Performance ◽  
Experimental Studies ◽  
Patient Specific ◽  
Wall Structure ◽  
Left Main ◽  
Element Analysis ◽  
Stent Expansion ◽  
Radial Strength ◽  
Different Diameters

AbstractLeft main (LM) coronary artery bifurcation stenting is a challenging topic due to the distinct anatomy and wall structure of LM. In this work, we investigated computationally and experimentally the mechanical performance of a novel everolimus-eluting stent (SYNERGY MEGATRON) purpose-built for interventions to large proximal coronary segments, including LM. MEGATRON stent has been purposefully designed to sustain its structural integrity at higher expansion diameters and to provide optimal lumen coverage. Four patient-specific LM geometries were 3D reconstructed and stented computationally with finite element analysis in a well-validated computational stent simulation platform under different homogeneous and heterogeneous plaque conditions. Four different everolimus-eluting stent designs (9-peak prototype MEGATRON, 10-peak prototype MEGATRON, 12-peak MEGATRON, and SYNERGY) were deployed computationally in all bifurcation geometries at three different diameters (i.e., 3.5, 4.5, and 5.0 mm). The stent designs were also expanded experimentally from 3.5 to 5.0 mm (blind analysis). Stent morphometric and biomechanical indices were calculated in the computational and experimental studies. In the computational studies the 12-peak MEGATRON exhibited significantly greater expansion, better scaffolding, smaller vessel prolapse, and greater radial strength (expressed as normalized hoop force) than the 9-peak MEGATRON, 10-peak MEGATRON, or SYNERGY (p < 0.05). Larger stent expansion diameters had significantly better radial strength and worse scaffolding than smaller stent diameters (p < 0.001). Computational stenting showed comparable scaffolding and radial strength with experimental stenting. 12-peak MEGATRON exhibited better mechanical performance than the 9-peak MEGATRON, 10-peak MEGATRON, or SYNERGY. Patient-specific computational LM stenting simulations can accurately reproduce experimental stent testing, providing an attractive framework for cost- and time-effective stent research and development.

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