Buckle Propagation in Pipelines Under Non-Uniform Pressure

2006 ◽  
Author(s):  
R. Talebpour ◽  
K. Abedi ◽  
A. R. M. Gharebaghi
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Local Buckling ◽  
Internal Flow ◽  
External Pressure ◽  
Numerical Results ◽  
Uniform Pressure ◽  
Element Analysis ◽  
Element Modeling ◽  
Buckle Propagation

Preventing the occurrence of local buckling due to external pressure is one of the main concerns in design of offshore pipelines. However, when a pipeline is designed for deepwater, prevention of the propagation of local buckling along the pipeline has more importance. Therefore, the study of buckle propagation phenomenon and its prevention is a subject of many researches in the past 25 years. Great amount of these researches have focused on appropriate estimation of buckle propagation pressure. In this paper, details of 3-D finite element modeling for buckle propagation simulation are outlined. In order to verify the accuracy and validity of the finite element modeling, the numerical results, obtained from nonlinear finite element analysis have been compared with the results of the experimental study on full-scale models, undertaken by C-FER Technologies, Canada, which have been published by Toscano et al. (2002). Comparison shows that the finite element results have very close agreement with the experimental behaviour. Also, in the present paper, numerical results of Toscano et al. are discussed; and the study shows that the proposed method, outlined in this paper, gives more appropriate results than the proposed method by Toscano et al. In addition, the buckle propagation of pipeline under the uniform external pressure as well as non-uniform pressure, due to the presence of the internal flow (when the pipe is not full of fluid) is studied. The change of buckle propagation pressure is determined by the proposed method.

Finite Element Analysis of Clamp-On Buckle Arrestor for Pipe-in-Pipe Flowlines by Reel-Lay Installation

2008 ◽  
Author(s):  
Jason Sun ◽  
Paul Jukes
Keyword(s):  
Finite Element ◽  
Deep Water ◽  
Pipe Wall ◽  
Mechanical Design ◽  
Local Buckling ◽  
External Pressure ◽  
Design Parameters ◽  
Element Analysis ◽  
Buckle Propagation ◽  
Buckle Arrestors

Development of deep water oil reservoirs are undertaken in the Gulf of Mexico (GoM) where the flowlines are installed in the water depths in excess of 3,050m (10,000ft). Deepwater external pressure becomes so significant that it makes local buckling or accidental collapse propagate along the pipeline. Such propagation will not stop until it reaches a region where the external pressure falls below the propagating pressure or where the pipe wall is strengthened. Field data indicates that once a buckle happens, the flowline could collapse many kilometers instantly. It concludes that buckle propagation could cause substantial economical impact if left uncontrolled. For pipe-in-pipe (PIP) flowline, due to lack of pressure differential, the outer pipe becomes a fragile component in terms of buckle propagation. One way to prevent the propagation of local buckling or collapse is to utilize the buckle arrestors of various types. Clamp-on buckle arrestor is so far the best choice for the flowlines to be installed by the Reel-Lay method. The objective of this paper is to present the results of a finite element (FE) study, to reveal the phenomena of collapsing/propagating of the pipe-in-pipe flowline, and to investigate the effectiveness of Clamp-on buckle arrestor for deep water flowlines. Sensitivities of key design parameters are explored with the purpose of guiding detail mechanical design of the clamp-on buckle arrestor.

scholarly journals Developing an Extended IFC Data Schema and Mesh Generation Framework for Finite Element Modeling

2019 ◽  
Vol 2019 ◽  
pp. 1-19
Author(s):  
Zhao Xu ◽  
Zezhi Rao ◽  
Vincent J. L. Gan ◽  
Youliang Ding ◽  
Chunfeng Wan ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Mesh Generation ◽  
Geometric Model ◽  
Information Modeling ◽  
Element Analysis ◽  
Element Modeling ◽  
The Finite Element Analysis ◽  
Ifc Standard

Mesh generation plays an important role in determining the result quality of finite element modeling and structural analysis. Building information modeling provides the geometry and semantic information of a building, which can be utilized to support an efficient mesh generation. In this paper, a method based on BRep entity transformation is proposed to realize the finite element analysis using the geometric model in the IFC standard. The h-p version of the finite element analysis method can effectively deal with the refined expression of the model of bending complex components. By meshing the connection model, it is suggested to adopt the method of scanning to generate hexahedron, which improves the geometric adaptability of the mesh model and the quality and efficiency of mesh generation. Based on the extension and expression of IFC information, the effective finite element structure information is extracted and extended into the IFC standard mode. The information is analyzed, and finally the visualization of finite element analysis in the building model can be realized.

A Meta-Object Based Approach to Finite Element Modeling

2001 ◽  
Author(s):  
Santosh Shanbhag ◽  
Ian R. Grosse ◽  
Jack C. Wileden ◽  
Alan Kaplan
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Production Model ◽  
Engineering Analysis ◽  
Demand Model ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Element Modeling ◽  
Molded Part ◽  
Analysis Models

Abstract With the integration of CAD and FEA software packages, design engineers who are not skilled in finite element analysis are performing finite element modeling and analysis. Furthermore, in the analysis of a system, engineers often make numerous modeling simplifications and analysis assumptions depending on the trade-off between cost, accuracy, precision or other engineering analysis objectives. Thus, reusability or interoperability of engineering analysis models is difficult and often impractical due to the wealth of knowledge involved in the creation of such models and the lack of formal methods to codify and explicitly represent this critical modeling knowledge. Most institutions and organizations have started documenting these simplifications and assumptions, making them understandable for the other engineers within the organization. However, this does not allow a seamless exchange of data or interoperability with other analysis models of similar or dissimilar nature. This plays a very important role in today’s market, which is moving away from the traditional make-to-stock production model to a build-to-demand model. We address these issues in this paper by adopting and extending the computer science concept of meta-object, and applying it in novel ways to the domain of FEA and the representation of finite element modeling knowledge. We present a taxonomy for engineering models that aids in the definition of the various object analysis classes. A simple beam analysis example, followed by a more realistic injection-molded part example. The latter example involves injection-mold filling simulation, thermal cooling, and part ejection analyses which are subclasses for a generic manufacturing analysis meta-object class. Prototype implementations of automated support for this meta-object approach to finite element modeling is in progress.

Contact Stiffness Parameters for Finite Element Modeling of Contact

2019 ◽  
Vol 799 ◽  
pp. 211-216
Author(s):  
Alina Sivitski ◽  
Priit Põdra
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Contact Stiffness ◽  
Influential Factors ◽  
Element Analysis ◽  
Normal Contact ◽  
Element Modeling ◽  
Contact Models ◽  
Machine Elements ◽  
Normal Contact Pressure

Contact modeling could be widely used for different machine elements normal contact pressure calculations and wear simulations. However, classical contact models as for example Hertz contact models have many assumptions (contact bodies are elastic, the contact between bodies is ellipse-shaped, contact is frictionless and non-conforming). In conditions, when analytical calculations cannot be performed and experimental research is economically inexpedient, numerical methods have been applied for solving such engineering tasks. Contact stiffness parameters appear to be one of the most influential factors during finite element modeling of contact. Contact stiffness factors are usually selected according to finite element analysis software recommendations. More precise analysis of contact stiffness parameters is often required for finite element modeling of contact.

Effects of Diameter to Thickness Ratio and External Pressure on the Velocity of Dynamic Buckle Propagation in Offshore Pipelines

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Z. Omrani ◽  
K. Abedi ◽  
A. R. Mostafa Gharabaghi
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Element Model ◽  
External Pressure ◽  
Thickness Ratio ◽  
Small Scale ◽  
Element Analysis ◽  
Models Comparison ◽  
Buckle Propagation ◽  
Exerted Pressure

In this paper, a numerical study of the dynamic buckle propagation, initiated in long pipes under external pressure, is presented. For a long pipe, due to the high exerted pressure, local instability is likely to occur; therefore, the prevention of its occurrence and propagation are very important subjects in the design of pipelines. The 3D finite element modeling of the buckle propagation is presented by considering the inertia of the pipeline and the nonlinearity introduced by the contact between its collapsing walls. The buckling and collapse are assumed to take place in the vacuum. The numerical results of the nonlinear finite element analysis are compared with the experimental results obtained by Kyriakides and Netto (2000, “On the Dynamics of Propagating Buckle in Pipelines,” Int. J. Solids Struct., 37, pp. 6843–6878) from a study on the small-scale models. Comparison shows that the finite element results have very close agreement with those of the experimental study. Therefore, it is concluded that the finite element model is reliable enough to be used for nonlinear collapse analysis of the dynamic buckle propagation in the pipelines. In this study, the effects of external pressure on the velocity of dynamic buckle propagation for different diameter to thickness ratios are investigated. In addition, the mathematical relations, based on the initiation pressure, are derived for the velocity of buckle propagation considering the diameter to thickness ratio of the pipeline. Finally, a relation for the buckle velocity as a function of the pressure and diameter to thickness ratio is presented.

Contact Stresses in Dovetail Attachments: Finite Element Modeling

1999 ◽  
Author(s):  
G. B. Sinclair ◽  
N. G. Comier ◽  
J. H. Griffin ◽  
G. Meda
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Stress Analysis ◽  
High Stress ◽  
Contact Stresses ◽  
Computational Effort ◽  
Element Analysis ◽  
Element Modeling ◽  
Stress Gradients

The stress analysis of dovetail attachments presents some challenges. These challenges stem from the high stress gradients near the edges of contact and from the nonlinearities attending conforming contact with friction. To meet these challenges with a finite element analysis, refined grids are needed with mesh sizes near the edges of contact of the order of one percent of the local radii of curvature there. A submodeling procedure is described which can provide grids of sufficient resolution in return for moderate computational effort. This procedure furnishes peak stresses near contact edges which are converging on a sequence of three submodel grids, and which typically do converge to within about five percent.

The Tip/Tilp Mirror Modal Analysis Based on Flexible Connection of Equivalent Spring

2014 ◽  
Vol 697 ◽  
pp. 226-229
Author(s):  
Cai Ling Wang ◽  
Hong Wei Wang
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Modal Analysis ◽  
Detection System ◽  
Mirror System ◽  
Test Results ◽  
Element Analysis ◽  
Element Modeling ◽  
The Finite Element Analysis ◽  
Resonance Detection

According to flexible connectivity of space stabilization system,This paper proposes the finite element analysis method using multiple equivalent spring connecting unit to replace the original flexible connections. And the elastic coefficient’s correspondence between the equivalent spring and the original spring were deduced. Using the equivalent spring method, the tip/tilt mirror system for finite element modeling is completed, After completion of the modal analysis, first-order resonant frequency is calculated. At last, the tip/tilt mirror system is tested in non-contact laser resonance detection system, And test results and modal analysis results were compared, and results show that the finite element modeling method of using equivalent spring connecting is effective. Provide constructive reference for subsequent tip/tilt mirror design, has a very important reference for similar projects.

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