Expansion Design Philosophy to Prevent Buckle Walking at Very Uneven Seabed

2009 ◽  
Author(s):  
Ragnar T. Igland ◽  
Marit Irene Kvittem ◽  
Dmitry Vysochinskiy
Keyword(s):  
Oil And Gas ◽  
Local Buckling ◽  
Design Parameters ◽  
Operational Conditions ◽  
Design Philosophy ◽  
Buckling Behavior ◽  
Start Up ◽  
Continuous Survey ◽  
Standard Design ◽  
Global Buckling

Subsea flowline development for a field on the Norwegian Continental Shelf comprises design of HP/HT flowlines for oil and gas transport from subsea manifolds. Flowline engineering faces several challenges related to flowlines crossing very uneven seabed. Among them is choosing an expansion design philosophy that minimizes the need for continuous survey and intervention work updates. Control of buckling behavior is ensured by use of rock berms. The standard design of the rock dumps according to [1] is based on buckle sharing criterion for axial friction capacity, which aims to control initiation of buckles. However, fulfilling the buckle sharing criterion alone does not provide sufficient control of pipeline behavior through the different operational conditions. In addition to buckle sharing criterion fulfillment [1], anchoring rock berms shall also ensure that the point of zero axial displacement is inside the berm for all operational conditions. This will give control over feed-in lengths and counter pipeline walking between sections. Criteria for ARBs are established, covering post buckle and shutdown conditions in addition to buckle sharing. Unstable buckle configuration during shutdown/start-up cycles is defined as buckle walking. Redistribution of feed-in between buckles is frequently observed as the cause of buckle walking. Use of uplift cover is avoided or minimized in order to eliminate extra axial friction and the uncertainty around such friction, and thus to guarantee that the sectioning by anchoring rock berms (ARBs) is working. Within each section between ARBs the axial force in the system is held at a minimum level by controlled buckling. The combination of isolated pipeline sections with minimum axial restraint within the section provides control over unstable buckling behavior. Thus the risk of unexpected buckles is minimized. This is particularly important for uneven seabed. 3D global buckling analyses are performed by ANSYS with upper bound, best estimate and lower bound design parameters for friction in accordance with [1] and capacity control for local buckling of pipeline in accordance with [2].

Overview of the Lateral Buckling and Walking Designs of Deepwater Pipelines in Offshore Brazil

2019 ◽  
Author(s):  
Rafael F. Solano ◽  
Carlos O. Cardoso ◽  
Bruno R. Antunes
Keyword(s):  
Oil And Gas ◽  
Design Guidelines ◽  
Mitigation Measures ◽  
Design Parameters ◽  
Clayey Soils ◽  
Lateral Buckling ◽  
Buckling Behavior ◽  
The World ◽  
Global Buckling ◽  
Subsea Pipelines

Abstract Last two decades have been marked by a significant evolution on the design of HP/HT subsea pipelines around the world. The HotPipe and SAFEBUCK JIPs can be seen as the first deepened developments in order to obtain safe design guidelines for subsea pipelines systems subjected to global buckling and walking behaviors. The adopted design approach have been to allow exposed pipeline buckles globally on seabed in a safe and controlled manner. Otherwise, the walking phenomenon has been in general mitigated constraining axial displacements by means of anchoring systems. After several design and installation challenges concerning lateral buckling and pipeline walking behaviors, nowadays there is a significant amount of deepwater pipelines operating with buckle initiators (triggers) as well as walking mitigation devices in offshore Brazil. Oil and gas pipelines, short gathering lines and long export lines, installed by reeling and J-lay methods, in other words different kinds of subsea pipelines have operated on very soft clayey soils and have formed planned lateral buckles as well as rogue buckles. This paper presents the main characteristics and design challenges of the deepwater pipelines subjected to the lateral buckling behavior, also highlighting mitigation measures to constrain the walking phenomenon of some pipelines. The relevant design results are highlighted as type and number of buckle triggers, buckle spacing, type and locations of walking mitigations. Envelopment of the main design parameters are mapped in order to identify some trends. Finally, survey images of operating pipelines are presented confirming behaviors predicted in the design phase.

Global Buckling Characteristics of Offshore Bundled Pipeline System

2021 ◽  
Author(s):  
Danar Tri Yurindatama ◽  
Nawin Singh ◽  
Vinod Pillai
Keyword(s):  
Actual Condition ◽  
Design Parameters ◽  
Pipeline System ◽  
Process Data ◽  
Standard Requirement ◽  
Buckling Behavior ◽  
Offshore Pipeline ◽  
Global Buckling ◽  
The Impact ◽  
Analytical Approaches

Abstract In recent years, the global buckling assessment of offshore pipelines in High Pressure-High Temperature (HPHT) condition become increasingly challenging since more complex pipeline system arrangement e.g. pipe(s) or cable(s) is strapped onto a larger pipeline, are rapidly utilized in many areas. Yet, the detailed guideline to assess the buckle of bundles remains unclear, therefore this study will focus to investigate on a methodical and reproducible approach to analyze in-service buckling behavior of bundled offshore pipeline system. The global buckling behavior of bundled offshore pipeline system in this study is investigated using commercial Finite Element (FE) software. Two carbon steel pipelines with different diameter are bundled and the buckling behavior is studied under the influence of buckle triggers. In the actual condition, the rogue buckle trigger is generated from OOS (out of straightness) or imperfection e.g. due to laying tolerance. Varying dimension parameter such as diameter ratio between the main pipeline and strapped pipeline are considered to understand the impact of this parameter on the buckle behavior. The study begins with a comparison of the results using numerical and analytical approaches on a straight pipeline in an unbuckled condition for validation purposes. The design parameters including wall thickness, process data, and pipe-soil interaction data, are varied since it influences the buckle behavior. In addition, some design parameter such as material properties and pipeline length will be adopted from a typical offshore pipeline project and the values are fixed so the exercise can focus on the most governing parameters. Following this, two numerical modelling methods, the equivalent properties method and the connector method, are presented in this study to simulate bundled systems. With a good agreement between the analytical and numerical approach, some buckle trigger is introduced on the numerical model of the bundled pipeline so the system is able to buckle and the behavior can be evaluated further. The strain level, lateral displacement, axial feed-in and pipe integrity shall be reported in the post-buckle conditions for both main pipe and strapped pipe as per current code and standard requirement. With more reliable results of buckling assessment for bundled pipeline system, it gives technical confidence and a major saving in both Capital Expenditure (CAPEX) and Operational Expenditure (OPEX). Industry has put serious effort through various Joint Industry Projects (JIP) to develop the global buckling assessment guideline in order to ensure long term integrity operation. Although the JIP guideline is predominantly for single pipeline system, similar assessment is demanded also for bundled pipeline system which described in this study. Key findings of the assessment are presented along with an overview of the design process and the typical mitigation techniques to be considered for similar subsea pipeline projects.

Designing Hierarchical IsoTruss Column Based on Controlling Multi-Buckling Behaviors

2021 ◽  
Author(s):  
Changliang Lai ◽  
Qianqian Sui ◽  
Hualin Fan
Keyword(s):  
Finite Element ◽  
Parametric Design ◽  
Local Buckling ◽  
Fe Model ◽  
The Finite Element Method ◽  
Buckling Modes ◽  
Buckling Behavior ◽  
Global Buckling ◽  
Buckling Failure ◽  
Theoretical Analyses

To develop large-span but ultralight lattice truss columns, a hierarchical IsoTruss column (HITC) was proposed. The multi-buckling behavior of the axially compressed HITC was analyzed by the finite element method (FEM) using a parametric approach in the framework of ANSYS parametric design language (APDL). It was demonstrated that the program enables efficient generation of the finite element (FE) model, while facilitating the parametric design of the HITC. Using this program, the effects of helical angles and brace angles on the buckling behavior of the HITC were investigated. Depending on the helical angles and brace angles, the HITCs mainly have three buckling modes: the global buckling, the first-order local buckling and the second-order local buckling. Theoretical multi-buckling models were established to predict the critical buckling loads. Buckling failure maps based on the theoretical analyses were also developed, which can be useful in preliminary design of such structures.

Effect of Implanted Delamination and Core Density on the Buckling Behavior of Sandwich Composites

2000 ◽  
Author(s):  
Hassan Mahfuz ◽  
Syful Islam ◽  
Leif Carlsson ◽  
Makeba Atkins ◽  
Shaik Jeelani
Keyword(s):  
Finite Element ◽  
Local Buckling ◽  
Sandwich Composites ◽  
Core Density ◽  
Sandwich Construction ◽  
Buckling Behavior ◽  
The Face ◽  
Global Buckling ◽  
Plane Compression ◽  
Overall Buckling

Abstract Foam core sandwich composites have been fabricated using innovative co-injection resin infusion technique and tested under in-plane compression. The sandwich construction consisted of Klegcell foam as core materials and S2-Glass/Vinyl ester composites as face sheets. Tests were conducted with various foam densities and also with implanted delamination between the core and the face sheet. The intent was to investigate the effect of core density, and the effect of core-skin debonds on the overall buckling behavior of the sandwich. Analytical and finite element calculations were also performed to augment the experimental observations. It has been observed that core density has direct influence on the global buckling of the sandwich panel, while embedded delamination seem to have minimal effect on both global as well as local buckling. Detailed description of the experimental work, finite element modeling and analytical calculations are presented in this paper.

Numerical Analysis of Debonded Honeycomb Sandwich Structure under Compressive Load

2013 ◽  
Vol 658 ◽  
pp. 227-231
Author(s):  
Tao Zhu ◽  
Jin Long Chen ◽  
Wen Ran Gong
Keyword(s):  
Finite Element ◽  
Local Buckling ◽  
Compressive Load ◽  
Sandwich Panels ◽  
Element Model ◽  
Damage Propagation ◽  
Buckling Behavior ◽  
Honeycomb Sandwich ◽  
Global Buckling ◽  
Honeycomb Sandwich Structure

In this paper, the finite element method (FEM) was applied to predict the local buckling behavior and the debond propagation in honeycomb sandwich panels with face-core debond under in-plane compressive load. The finite element model of the sandwich panel was built, the cohesive element was used to model the adhesive between faces and core, the influence of the debond shape and size on the failure mode, critical buckling load and residual compressive strength of the sandwich panels was investigated, the rule of the damage propagation was summarized. The compression strength of the sandwich panels with through-width face-core debond decreases with increasing debond length. For the panels with central circular debond, when the diameter is less than 15mm, the panels will failure by global buckling and the debond will not grow. When the diameter is greater than 15mm, the panels will failure by local buckling and the critical load strongly decreases with increasing debond diameter. In addition, the direction of debond growth is predominantly perpendicular to the applied load.

scholarly journals Buckling Behavior of Non-Retrofitted and FRP-Retrofitted Steel CHS T-Joints

2021 ◽  
Vol 11 (7) ◽  
pp. 3098
Author(s):  
Amin Yazdi ◽  
Maria Rashidi ◽  
Mohammad Alembagheri ◽  
Bijan Samali
Keyword(s):  
Compressive Loading ◽  
Local Buckling ◽  
Buckling Mode ◽  
T Joints ◽  
Hollow Section ◽  
Frp Composite ◽  
Buckling Behavior ◽  
Global Buckling ◽  
Post Buckling ◽  
Circular Hollow Section

This paper aims to investigate the buckling behavior of circular hollow section (CHS) T-joints in retrofitted and non-retrofitted states under axial brace compressive loading. For this purpose, two types of analysis are carried out. The first one is evaluating the critical buckling load in various tubular joints, and the other one is investigating the post-buckling behavior after each buckling mode. More than 180 CHS T-joints with various normalized geometric properties were numerically modeled in non-retrofitted state to compute their governing buckling mode, i.e., chord ovalization, brace local, or global buckling. Then three joints with different buckling modes were selected to be retrofitted by fiber-reinforced polymer (FRP) patches to illustrate the improving effect of the FRP wrapping on the post-buckling performance of the retrofitted joints. In addition, FRP composite failures were investigated. The results indicate that the FRP retrofitting is able to prevent the brace local buckling, and that matrix failure is the most common composite failure in the retrofitted joints.

Critical Strain of Carbon Nanotubes: An Atomic-Scale Finite Element Study

2006 ◽  
Vol 74 (2) ◽  
pp. 347-351 ◽  
Author(s):  
X. Guo ◽  
A. Y. T. Leung ◽  
H. Jiang ◽  
X. Q. He ◽  
Y. Huang
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element ◽  
Critical Strain ◽  
Local Buckling ◽  
Atomic Scale ◽  
Energy Curve ◽  
Outer Diameter ◽  
Covalent Bonds ◽  
Buckling Behavior ◽  
Global Buckling

This paper employs the atomic-scale finite element method (AFEM) to study critical strain of axial buckling for carbon nanotubes (CNTs). Brenner et al. “second-generation” empirical potential is used to model covalent bonds among atoms. The computed energy curve and critical strain for (8, 0) single-walled CNT (SWNT) agree well with molecular dynamics simulations. Both local and global buckling are achieved, two corresponding buckling zones are obtained, and the global buckling behavior of SWNT with a larger aspect ratio approaches gradually to that of a column described by Euler’s formula. For double-walled CNTs with smaller ratio of length to outer diameter, the local buckling behavior can be explained by conventional shell theory very well. AFEM is an efficient way to study buckling of CNTs.

Study on the Local Buckling Behavior of Steel Equal Angle Members under Axial Compression with the Steel Strength Variation

2011 ◽  
Vol 374-377 ◽  
pp. 2430-2436
Author(s):  
Gang Shi ◽  
Zhao Liu ◽  
Yong Zhang ◽  
Yong Jiu Shi ◽  
Yuan Qing Wang
Keyword(s):  
Finite Element ◽  
Axial Compression ◽  
High Strength Steel ◽  
Local Buckling ◽  
Steel Structures ◽  
High Strength ◽  
Element Analysis ◽  
Equal Angle ◽  
Buckling Behavior ◽  
Steel Strength

High strength steel sections have been increasingly used in buildings and bridges, and steel angles have also been widely used in many steel structures, especially in transmission towers and long span trusses. However, high strength steel exhibits mechanical properties that are quite different from ordinary strength steel, and hence, the local buckling behavior of steel equal angle members under axial compression varies with the steel strength. However, there is a lack of research on the relationship of the local buckling behavior of steel equal angle members under axial compression with the steel strength. A finite element model is developed in this paper to analyze the local buckling behavior of steel equal angle members under axial compression, and study its relationship with the steel strength and the width-to-thickness ratio of the angle leg. The finite element analysis (FEA) results are compared with the corresponding design method in the American code AISC 360-05, which provides a reference for the related design.

Operational conditions for start-up and nitrate-feeding in an anoxic biotrickling filtration process at pilot scale

2016 ◽  
Vol 285 ◽  
pp. 83-91 ◽  
Author(s):  
Fernando Almenglo ◽  
Martín Ramírez ◽  
José Manuel Gómez ◽  
Domingo Cantero
Keyword(s):  
Pilot Scale ◽  
Filtration Process ◽  
Operational Conditions ◽  
Start Up

Energy Harvesting Under Harsh Conditions for the Oil & Gas Upstream Industry

2021 ◽  
Author(s):  
José Correia ◽  
Cátia Rodrigues ◽  
Ricardo Esteves ◽  
Ricardo Cesar Bezerra de Melo ◽  
José Gutiérrez ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Oil And Gas ◽  
Electrical Energy ◽  
Development Stage ◽  
Gas Extraction ◽  
Power Monitoring ◽  
Operational Conditions ◽  
Wide Range ◽  
First Time ◽  
Harsh Conditions

Abstract Environmental and safety sensing is becoming of high importance in the oil and gas upstream industry. However, present solutions to feed theses sensors are expensive and dangerous and there is so far no technology able to generate electrical energy in the operational conditions of oil and gas extraction wells. In this paper it is presented, for the first time in a relevant environment, a pioneering energy harvesting technology based on nanomaterials that takes advantage of fluid movement in oil extraction wells. A device was tested to power monitoring systems with locally harvested energy in harsh conditions environment (pressures up to 50 bar and temperatures of 50ºC). Even though this technology is in an early development stage this work opens a wide range of possible applications in deep underwater environments and in Oil and Gas extraction wells where continuous flow conditions are present.

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