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.

scholarly journals Strength & Stability Analysis of Straight Shafted Pile Foundation in Cohesive Soil Condition using Finite Element Analysis

2021 ◽  
Vol 9 (VII) ◽  
pp. 3612-3617
Author(s):  
Yogesh K S
Keyword(s):  
Finite Element ◽  
Carrying Capacity ◽  
Pile Foundation ◽  
Numerical Technique ◽  
Expansive Soil ◽  
Cohesive Soil ◽  
Load Carrying Capacity ◽  
Deep Foundation ◽  
Element Analysis ◽  
Load Carrying

Pile foundation is one of the effective forms of deep foundation. This is to be used where the load has to be transferred to deeper layers of soil and it can with stand uplift forces in foundations in expansive soil and also in case of floating foundations. The finite element method is one of the most versatile and comprehensive numerical technique which can be used for analysis of structures or solids of complex shapes and complicated boundary conditions. There are different variables which influence the load carrying capacity of pile foundation. But only some of those have significant influence on load carrying capacity. Here those variables are considered and the variation of load carrying capacity with the change in value of those variables is observed. Those variables are pile length and pile diameter, analysis of pile foundation was carried out to determine the ultimate load carrying capacity of pile for different lengths and diameters in cohesive soil, the corresponding settlement was also determined.

Design of Micro Heat Spreaders for Electronic Cooling

2004 ◽  
Author(s):  
P. Chiarot ◽  
P. Sullivan ◽  
R. Ben Mrad
Keyword(s):  
Electronic Cooling ◽  
Operating Conditions ◽  
Silicon On Insulator ◽  
Maximum Temperature ◽  
Heat Spreader ◽  
Element Analysis ◽  
Heat Spreaders ◽  
Number Curve ◽  
The Given ◽  
Membrane Deflection

This work presents an active Micro Heat Spreader (MHS) for use in electronic cooling. The device includes four reservoir chambers and is actuated using membrane deflection. An investigation is performed using Finite Element Analysis to determine the performance characteristics of the MHS. Two operating conditions for the actuation order of the membranes are considered. Dimensional similitude is used to obtain a single maximum temperature versus Reynolds number curve for the device at the given operating condition and Prandtl number. Fabrication of the MHS is proposed using the Silicon-on-Insulator (SOI) technique and actuation of the membranes can be achieved using thin film PZT.

In-Service Buckling Assessment: The Correct Use of Engineering Analysis Tools

2015 ◽  
Author(s):  
Lorenzo Bartolini ◽  
Lorenzo Marchionni ◽  
Sara Tassetti ◽  
Alberto Battistini ◽  
Luigino Vitali
Keyword(s):  
Service Condition ◽  
Operating Conditions ◽  
Mitigation Measures ◽  
Limited Information ◽  
Long Distance ◽  
Offshore Pipeline ◽  
Global Buckling ◽  
Integrity Management ◽  
The Subject ◽  
Design Analyses

There is consensus on the need for in-service buckling analyses to assess the integrity of both flowlines and long distance trunklines subject to HP/HT service condition. The extent of the analyses and supporting survey depends on the severity of the application. In the last two decades, the pipeline industry has gained significant experience in both the design and operation of pipeline systems exposed to global buckling. Actually, the early 90s have been a watershed: before the phenomenon was just known (theoretically), then it was seen...as soon as pipeline integrity management programmes have been introduced in the offshore pipeline industry practices. Although, limited information have been documented in the open literature, now as then. Several efforts have been dedicated to develop design methods and procedures suitable for operating pipeline safely as well as protecting the population, environmental resources and assets. At the beginning, there was a gap to be closed as specific mitigation measures were never designed. Nowadays, thanks to computational progress, it seems that the attention is addressed to face the uncertainties affecting the subject matter but, sometime, leading to overdesign. The scope of the paper is to present aspects of global buckling design analyses that were performed in recent projects with the aim to highlight the challenges and the risks, the accuracy or the limitation of the methods, the feedback and the lesson learnt of real installed pipelines under operating conditions.

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.

Global Buckling Assessment of High Pressure and High Temperature (HP/HT) Offshore Pipeline

2010 ◽  
Author(s):  
Seung-Ho Yang ◽  
Jong-Jin Jung ◽  
Yun-Hak Kim ◽  
Woo-Seob Lee ◽  
Jong-Bae Kim
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Pipeline System ◽  
Fe Model ◽  
Offshore Pipelines ◽  
Buckling Behavior ◽  
High Pressure High Temperature ◽  
Offshore Pipeline ◽  
Global Buckling ◽  
The Stability

In recent years, requirement for the consideration of global buckling due to high pressure/high temperature (HP/HT) condition has increased in the detailed design of offshore pipelines on a seabed. The interaction between pipeline and seabed including support structures or sleepers gives a significant effect on buckling behavior. Global lateral buckling analysis has been carried out to assess the stability of offshore HP/HT pipelines considering the interaction between HP/HT submarine pipeline system/foundation structure and seabed. A non-linear finite element method is used in the present static analysis using the ABAQUS program. The FE model considers concrete sleepers as well as 3-D profile of the seabed. The stress distribution and lateral amplitude of the pipeline were evaluated and remedial measures were suggested to ensure that pipe stresses and strains are kept within allowable limits. Sleepers are designed as a buckle trigger which can provide artificial imperfection to allow pipe to move laterally and mitigate axial force. Comparative study could provide design strategy of pipeline related to sleeper supports.

scholarly journals A numerical technique for a general form of nonlinear fractional-order differential equations with the linear functional argument

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Khalid K. Ali ◽  
Mohamed A. Abd El salam ◽  
Emad M. H. Mohamed
Keyword(s):  
Differential Equations ◽  
Collocation Method ◽  
Fractional Order ◽  
Linear Functional ◽  
Numerical Technique ◽  
Operational Matrix ◽  
Fractional Order Differential Equations ◽  
The Given ◽  
Functional Argument ◽  
Special Case

AbstractIn this paper, a numerical technique for a general form of nonlinear fractional-order differential equations with a linear functional argument using Chebyshev series is presented. The proposed equation with its linear functional argument represents a general form of delay and advanced nonlinear fractional-order differential equations. The spectral collocation method is extended to study this problem as a discretization scheme, where the fractional derivatives are defined in the Caputo sense. The collocation method transforms the given equation and conditions to algebraic nonlinear systems of equations with unknown Chebyshev coefficients. Additionally, we present a general form of the operational matrix for derivatives. A general form of the operational matrix to derivatives includes the fractional-order derivatives and the operational matrix of an ordinary derivative as a special case. To the best of our knowledge, there is no other work discussed this point. Numerical examples are given, and the obtained results show that the proposed method is very effective and convenient.

scholarly journals A Finite Element Study on Compressive Resistance Degradation of Square and Circular Steel Braces under Axial Cyclic Loading

2021 ◽  
Vol 11 (13) ◽  
pp. 6094
Author(s):  
Hubdar Hussain ◽  
Xiangyu Gao ◽  
Anqi Shi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cyclic Loading ◽  
Slenderness Ratio ◽  
Hysteretic Behavior ◽  
Element Analysis ◽  
Section Shape ◽  
Axial Cyclic Loading ◽  
Global Buckling ◽  
Parametric Studies

In this study, detailed finite element analysis was conducted to examine the seismic performance of square and circular hollow steel braces under axial cyclic loading. Finite element models of braces were constructed using ABAQUS finite element analysis (FEA) software and validated with experimental results from previous papers to expand the specimen’s matrix. The influences of cross-section shape, slenderness ratio, and width/diameter-to-thickness ratio on hysteretic behavior and compressive-tensile strength degradation were studied. Simulation results of parametric studies show that both square and circular hollow braces have a better cyclic performance with smaller slenderness and width/diameter-to-thickness ratios, and their compressive-tensile resistances ratio significantly decreases from cycle to cycle after the occurrence of the global buckling of braces.

Buckling characteristics of cut-out borne composite stiffened hyperbolic paraboloid shell panel

2021 ◽  
pp. 146442072110058
Author(s):  
Sarmila Sahoo
Keyword(s):  
Finite Element ◽  
Orientation Angle ◽  
Buckling Load ◽  
Benchmark Problems ◽  
Hyperbolic Paraboloid ◽  
Element Analysis ◽  
Load Effect ◽  
Global Buckling ◽  
Fiber Orientation Angle ◽  
Shell Panel

The present study investigates buckling characteristics of cut-out borne stiffened hyperbolic paraboloid shell panel made of laminated composites using finite element analysis to evaluate the governing differential equations of global buckling of the structure. The finite element code is validated by solving benchmark problems from literature. Different parametric variations are studied to find the optimum panel buckling load. Laminations, boundary conditions, depth of stiffener and arrangement of stiffeners are found to influence the panel buckling load. Effect of different parameters like cut-out size, shell width to thickness ratio, degree of orthotropy and fiber orientation angle of the composite layers on buckling load are also studied. Parametric and comparative studies are conducted to analyze the buckling strength of composite hyperbolic paraboloid shell panel with cut-out.

Research on the Structural Performance of Large-Tonnage Gantry Crane

2013 ◽  
Vol 823 ◽  
pp. 247-250
Author(s):  
Jie Dong ◽  
Wen Ming Cheng ◽  
Yang Zhi Ren ◽  
Yu Pu Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Theoretical Calculations ◽  
Complex Structure ◽  
Early Period ◽  
Operating Conditions ◽  
Structural Performance ◽  
Gantry Crane ◽  
Element Analysis ◽  
Design And Manufacture

Because of the huge lifting weight and complex structure of large-tonnage gantry crane and in order to effectively design and review it, this paper aims to carry out a research on its structural performance based on the method of theoretical calculation and finite element analysis. During the early period of design, the method of theoretical calculations is adopted, and after specific design it comes the finite element analysis, so as to get the results of analysis under a variety of operating conditions, which illustrates that the structural design and review of large-tonnage gantry crane based on theoretical calculations and finite element are feasible, and also verifies that the method of finite element is an effective way to find a real dangerous cross-section, thus providing the basis for the design and manufacture of the crane structure.

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