Recent Experience in the Lateral Buckling Design of Medium to Large Diameter Pipelines

2012 ◽  
Author(s):  
Maša Branković ◽  
Benjamin Anderson ◽  
Edwin Shim ◽  
Hammam Zeitoun ◽  
Eu Jeen Chin
Keyword(s):  
Large Diameter ◽  
Design Guidelines ◽  
Operating Conditions ◽  
Recent Experience ◽  
Lateral Buckling ◽  
High Pressure High Temperature ◽  
Critical Buckling Force ◽  
Global Buckling ◽  
Design Solutions ◽  
Definition Of

In the last decade and a half, the pipeline industry has gained significant experience in both the design and operation of pipeline systems exposed to lateral buckling. JIPs, design guidelines and recommended practices such as SAFEBUCK (Reference [1]), HOTPIPE (Reference [2]) and DNV RP-F110 (Reference [3]), together with operational feedback have significantly contributed to the development of comprehensive methods to determine robust lateral buckling design solutions. Most of this knowledge has been gained from understanding the behaviour of HP/HT (high pressure/ high temperature) small, light diameter systems, which buckle more predictably at operating conditions well below design conditions. Medium to large diameter, concrete coated pipelines are generally considered to be less prone to lateral buckling by comparison (due to expected milder design conditions), however the consequence of their buckling is far more severe and can prove extremely difficult to control. Fundamentally, the knowledge acquired and general lateral buckling design methodologies developed for HP/HT systems can be applied for the design of larger, heavier pipelines, however there are a number of key differences in the behaviour of both systems which warrant special considerations. Key considerations include (a), effective axial force and critical buckling force development (impacting susceptibility and initiation considerations), (b) severe post-buckle response on-seabed (impacting the acceptance of uncontrolled buckling for definition of buckle trigger spacing and extents), and (c), the consequence of introducing buckle triggers. Additional design complexity is introduced for systems installed in shallow water, which are exposed to more severe metocean conditions than deepwater HP/ HT systems. This requires heavy concrete weight coating (CWC) for stabilisation, resulting in strain localisation at field joints, concrete stiffening effects and complex interaction with hydrodynamic loading, typically ‘competing against’ intuitive global buckling design. All of the above factors result in lateral buckling design solutions for medium to large diameter, concrete coated pipelines becoming rather challenging.

On Pipeline Lateral Buckling: Lessons Learned and Current Design Challenges

2012 ◽  
Author(s):  
Emil A. Maschner ◽  
Basel Abdalla
Keyword(s):  
Cost Effective ◽  
Lessons Learned ◽  
Operating Conditions ◽  
Design Solution ◽  
Lateral Buckling ◽  
Diverse Range ◽  
Applied Loading ◽  
Direct Design ◽  
Safety Margins ◽  
Global Buckling

The subject of lateral buckling design in recent years has by necessity become increasingly more involved as pipeline projects have moved into more difficult environments where there is a need for optimized economic solutions with assured through-life reliability. The authors have had direct design responsibility and specialist involvement with a large number of projects covering a diverse range of environments, single or PIP systems, variable product characteristics and operating conditions, external applied loading type, and geographical installation limitations. These include shallow and deep water, large thin walled and small thick walled diameter pipes, flat to undulating hard to soft seabed, variable cohesive and non-cohesive surficial soil types and various other project considerations which have impacted on the chosen design solution. The purpose of this paper will be to highlight aspects of global buckling design associated with reliable in place systems and conversely those aspects associated with integrity risks to the as-laid operational pipelines. A review of past project challenges along with a commentary as to the state of the art at the time gives an opportunity to evaluate risks and challenges being faced on current projects. Particularly, as it seeks to develop ever more cost effective designs with proven robustness but optimized safety margins for the installation and operation of HT/HP pipelines in marginal fields.

Offshore Pipeline Embedment in Cohesive Soil: A Comparison Between Existing and CEL Solutions

2011 ◽  
Author(s):  
Han Shi ◽  
Jason Sun ◽  
Kabir Hossain ◽  
Ayman Eltaher ◽  
Paul Jukes
Keyword(s):  
Numerical Technique ◽  
Cohesive Soil ◽  
Soil Condition ◽  
Operating Conditions ◽  
Element Analysis ◽  
High Pressure High Temperature ◽  
Offshore Pipeline ◽  
Global Buckling ◽  
The Given ◽  
Geotechnical Problems

A common issue confronted by engineers in analyzing high pressure high temperature (HPHT) pipelines for installation and operating conditions is pipe-soil interaction. For installation, a key concern is whether the soil can generate sufficient resistance to allow the pipeline to be laid on the curve. For operation, a concern is whether the pipeline structural stress can be controlled and mitigated, for the given soil condition, under conditions of thermal expansion and potential global buckling. In both scenarios, pipeline embedment is a critical parameter as it is directly related to soil resistances to the pipeline stability. Previous studies have used experimental, analytical and numerical methods to provide estimates to the pipe embedment during the laying operation. The recently developed Coupled Eulerian-Lagrange (CEL) finite element analysis (FEA) method provides a promising numerical technique in analyzing large-deformation geotechnical problems, such as pipeline embedment analysis. This paper uses this approach, together with currently available embedment solutions, to cross-validate these methods for cohesive soils.

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.

Reliability of Lateral Buckling Formation From Planned and Unplanned Buckle Sites

2008 ◽  
Author(s):  
Andrew Rathbone ◽  
Mahmoud Abdel-Hakim ◽  
Gary Cumming ◽  
Knut To̸rnes
Keyword(s):  
Risk Assessment ◽  
High Pressure ◽  
Quantitative Risk Assessment ◽  
Design Solution ◽  
Lateral Buckling ◽  
Detailed Design ◽  
High Pressure High Temperature ◽  
Global Buckling ◽  
Subsea Pipelines ◽  
Design Stress

Global buckling for exposed HPHT (High Pressure / High Temperature) subsea pipelines is an important feature that needs to be assessed during detailed design. By safely triggering controlled buckles at predetermined locations and considering the potential for rogue buckles to be triggered by seabed or pipelay out-of-straightness features, a robust design solution can be obtained. This paper presents a methodology whereby quantitative risk assessment may be carried out on the reliability of lateral buckling initiation systems, considering the pipeline in its entirety, rather than considering each intended buckle individually. This method accounts for buckle interaction when calculating the post-buckle loads, and allows simple incorporation of potential rogue sites through vertical and/or horizontal out-of-straightness. The results of the risk assessment can be defined in terms of buckle formation reliability, and design stress/strain criteria.

Global Buckling Mitigation of Buried Pipelines: Lateral Resistance Assessment

2015 ◽  
Author(s):  
Martin Gallegillo ◽  
Guillaume Hardouin
Keyword(s):  
Design Guidelines ◽  
Buried Pipelines ◽  
Lateral Buckling ◽  
Element Analysis ◽  
Upheaval Buckling ◽  
Lateral Resistance ◽  
Rock Cover ◽  
Global Buckling ◽  
Cover Design ◽  
Analytical Tools

This paper presents an approach to rock cover design for un-trenched pipelines installed on the seabed and rock-dumped for protection against dropped objects, anchor chain impact and fishing/trawling activities. This is found in some North Sea locations which present challenging conditions for trenching while protection is necessary due to intensive fishing activities. Under these circumstances the pipeline must remain within the rock berm and, hence, it must be designed against global buckling. Whereas there are clear design guidelines addressing upheaval buckling behaviour, the resistance to lateral buckling to maintain a pipeline within the rock berm has received less attention in the literature. The aim of this paper is to present a method to design a rock berm to mitigate against lateral buckling of rock-dumped pipelines based on the horizontal out-of-straightness survey data provided to the designer. The main challenges associated with this activity at different design phases are also introduced, including the use of analytical tools as well as detailed finite element analysis.

scholarly journals A theoretical and numerical approach for selecting miniaturized antenna topologies on magneto-dielectric substrates

2015 ◽  
Vol 7 (3-4) ◽  
pp. 369-377 ◽  
Author(s):  
Alex Pacini ◽  
Alessandra Costanzo ◽  
Diego Masotti
Keyword(s):  
Near Field ◽  
Dielectric Materials ◽  
Numerical Approach ◽  
Operating Conditions ◽  
Microwave Range ◽  
Dielectric Substrates ◽  
Full Wave ◽  
Miniaturized Antenna ◽  
Wavelength Radiation ◽  
Definition Of

An increasing interest is arising in developing miniaturized antennas in the microwave range. However, even when the adopted antennas dimensions are small compared with the wavelength, radiation performances have to be preserved to keep the system-operating conditions. For this purpose, magneto-dielectric materials are currently exploited as promising substrates, which allows us to reduce antenna dimensions by exploiting both relative permittivity and permeability. In this paper, we address generic antennas in resonant conditions and we develop a general theoretical approach, not based on simplified equivalent models, to establish topologies most suitable for exploiting high permeability and/or high-permittivity substrates, for miniaturization purposes. A novel definition of the region pertaining to the antenna near-field and of the associated field strength is proposed. It is then showed that radiation efficiency and bandwidth can be preserved only by a selected combinations of antenna topologies and substrate characteristics. Indeed, by the proposed independent approach, we confirm that non-dispersive magneto-dielectric materials with relative permeability greater than unit, can be efficiently adopted only by antennas that are mainly represented by equivalent magnetic sources. Conversely, if equivalent electric sources are involved, the antenna performances are significantly degraded. The theoretical results are validated by full-wave numerical simulations of reference topologies.

Improving the Volumetric Efficiency of the Axial Piston Pump

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
Shu Wang
Keyword(s):  
Operating Conditions ◽  
Volumetric Efficiency ◽  
Valve Plate ◽  
Piston Pump ◽  
Efficient Design ◽  
Axial Piston Pumps ◽  
Definition Of ◽  
Engineering Practices ◽  
First Time ◽  
Axial Piston

The volumetric efficiency is one of the most important aspects of system performance in the design of axial piston pumps. From the standpoint of engineering practices, the geometric complexities of the valve plate (VP) and its multiple interactions with pump dynamics pose difficult obstacles for optimization of the design. This research uses the significant concept of pressure carryover to develop the mathematical relationship between the geometry of the valve plate and the volumetric efficiency of the piston pump. For the first time, the resulting expression presents the theoretical considerations of the fluid operating conditions, the efficiency of axial piston pumps, and the valve plate designs. New terminology, such as discrepancy of pressure carryover (DPC) and carryover cross-porting (CoCp), is introduced to explain the fundamental principles. The important results derived from this study can provide clear recommendations for the definition of the geometries required to achieve an efficient design, especially for the valve plate timings. The theoretical results are validated by simulations and experiments conducted by testing multiple valve plates under various operating conditions.

Experimental Investigation on the Rubbing Process of Labyrinth Seals Considering the Material Combination

2020 ◽  
Author(s):  
Lisa Hühn ◽  
Oliver Munz ◽  
Corina Schwitzke ◽  
Hans-Jörg Bauer
Keyword(s):  
Turbine Blades ◽  
Design Guidelines ◽  
Operating Conditions ◽  
Contact Forces ◽  
Experimental Investigations ◽  
Process Data ◽  
Labyrinth Seals ◽  
Material Combination ◽  
Higher Temperature ◽  
And Control

Abstract Labyrinth seals are used to prevent and control the mass flow rate between rotating components. Due to thermally and mechanically induced expansions during operation and transient flight maneuvers, a contact, the so-called rubbing process, between rotor and stator cannot be excluded. A large amount of rubbing process data concerning numerical and experimental investigations is available in public literature as well as at the Institute of Thermal Turbomachinery (ITS). The investigations were carried out for different operating conditions, material combinations, and component geometries. In combination with the experiments presented in this paper, the effects of the different variables on load due to rubbing are compared, and discussed with the focus lying on the material combination. The influence of the material on the loads can be identified as detailed as never before. For example, the contact forces in the current experiments are higher due to a higher temperature resistance of Young’s modulus. The analysis will also be based on the rubbing of turbine blades. Design guidelines are derived for labyrinth seals with improved properties regarding tolerance of rub events. Based on the knowledge obtained, guidelines for designing reliable labyrinth seals for future engines are discussed.

Evaluation of Design Premises and Uncertainties on the Thermo-Mechanical Behavior of a Subsea Pipeline

2014 ◽  
Author(s):  
Bruno Reis Antunes ◽  
Rafael Familiar Solano ◽  
Alexandre Hansen
Keyword(s):  
Formation Process ◽  
Mechanical Design ◽  
Design Stage ◽  
Stress And Strain ◽  
Lateral Buckling ◽  
Friction Factors ◽  
Global Buckling ◽  
Pipeline Route ◽  
Seabed Bathymetry ◽  
Subsea Pipelines

Buckle formation process is a key subject for the design of subsea pipelines laid on the seabed and operating under high pressure and high temperature (HP/HT) conditions. When the controlled lateral buckling methodology is adopted triggers are placed along pipeline route in order to increase the buckle formation probability in specific locations, sharing pipeline expansion between these sites and reducing the level of stress and strain in each buckle. Despite of its importance, buckle formation process is influenced by several parameters such as the seabed bathymetry, engineered triggers, lateral out-of-straightness (OOS) and pipe-soil interaction. While the first two items above can be defined with reasonable accuracy at previous stages of design, lateral OOS will only be known with tolerable confidence after pipeline installation. The level of uncertainty related to pipe-soil interaction is also considerable since pipeline embedment and friction factors are estimated using equations that include empirical correlations and field collected data. In addition these parameters are influenced by the installation process. Due to these uncertainties, conservative premises are usually assumed in order to obtain a robust pipeline thermo-mechanical design. After pipeline installation and/or start of operation an investigation can be performed in order to confirm the assumptions considered in the design. This paper presents a comparison of premises adopted during design stage of a pipeline based on the controlled lateral buckling methodology and the feedback obtained with the post-lay survey performed. After a brief introduction, pipeline embedment, global buckling at crossings, lateral OOS and sleepers’ height are some of the subjects addressed. Finally, conclusions and recommendations are presented in order to support future similar projects.

A Proposal for Performance Criteria for Propulsion Losses Due to Ship Steering

1982 ◽  
Vol 104 (2) ◽  
pp. 158-165 ◽  
Author(s):  
R. E. Reid
Keyword(s):  
High Speed ◽  
Operating Conditions ◽  
Relative Performance ◽  
Performance Criteria ◽  
Ship Steering ◽  
Calm Water ◽  
Simulation Results ◽  
Definition Of ◽  
Hydrodynamic Data

The problem of definition of propulsion loss related to ship steering is addressed. Performance criteria representative of propulsion losses due to steering over a range of operating conditions including operation in calm water and a seaway are considered. Criteria are derived from strict analytical considerations and from empirical assumptions based on experimentally derived hydrodynamic data. The applicability of these various criteria and the implications for both assessment of relative performance of existing ship autopilots and for the design of new steering controllers is discussed in relation to simulation results for a high-speed containership.

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