Comparison of Numerical Results and Design Criteria for Buckle Propagation and Buckle Arrestor Design

2006 ◽  
Author(s):  
Thomas Plonski ◽  
Gundula Stadie-Frohbo¨s ◽  
Gordon Jokisch
Keyword(s):  
Wall Thickness ◽  
External Pressure ◽  
Design Criterion ◽  
Numerical Results ◽  
Design Criteria ◽  
Technical Solution ◽  
Offshore Pipelines ◽  
External Impact ◽  
Buckle Propagation ◽  
Buckle Arrestors

Buckle propagation is a relevant design criterion for deep-water offshore pipelines. Imposed by external impact or local bending, e.g. during laying, a local buckle can be initiated, thereby decreasing the collapse strength of the pipeline. As a result of the high ambient external pressure, the buckle can start to propagate. Several design criteria for buckle propagation exist. This paper compares different design criteria with numerical results to obtain an impression of the levels of conservatism applied in the various codes. In most design cases, it is not suitable to avoid buckle propagation by using an increased wall thickness over the entire pipeline. Therefore, buckle arrestors are installed to stop the propagation. The common technical solution is to install sections of thicker pipeline, which requires that the buckle arrestor wall thickness and the length of the buckle arrestor have to be determined during design. A distinction is drawn between short and long buckle arrestors. Both cases are considered here. The design of the buckle arrestor can be carried out by using well-known criteria, such as the criteria developed by Kyriakides, Langner or Torselletti et al. These criteria are compared with experimental data. Numerical calculations are carried out and the results are compared with the design criteria.

Deepwater Pipelines: Reliability of Finite Element Models in the Prediction of Collapse and Collapse Propagation Loads

2006 ◽  
Author(s):  
Rita G. Toscano ◽  
Eduardo N. Dvorkin
Keyword(s):  
Finite Element ◽  
External Pressure ◽  
Numerical Results ◽  
Geometrical Parameters ◽  
Finite Element Models ◽  
External Diameter ◽  
Limit States ◽  
Limit Loads ◽  
Steel Pipes ◽  
Buckle Arrestors

In the design of pipelines it is of utmost importance to use validated numerical tools, usually finite element models, to reliably determine the structural limit loads. Also for steel pipes manufacturers it is very important, for establishing the set-up of their production processes, to be able to analyze using validated finite element models the effect that different manufacturing imperfections have on the pipe limit loads (e.g. “ovalization” of the external diameter, eccentricity, residual stresses, etc.). For deepwater pipelines the most relevant limit states that need to be analyzed are the collapse and collapse propagation under different combinations of external pressure and bending. In the second section of this paper we discuss the finite element models that we developed to predict the collapse and collapse propagation of seamless steel pipes under external pressure and bending. The validation of these models was performed comparing the numerical results with experimental results obtained at CFER (Edmonton, Canada) [1] and at our lab for the pre-collapse and post-collapse regimes. In deepwater pipelines, in order to prevent the propagation of collapse failures through the pipeline length, buckle arrestors are used. In the third section of this paper we review the finite element models that we developed to predict buckle arrestors cross-over external pressures. The validation of these models was performed comparing the numerical results with experimental ones obtained at our lab for different ratios [arrestor thickness/pipe thickness] corresponding to either the flattening or flipping cross-over mechanisms [2]. Finally in the fourth section of this paper the validated finite element models are used to perform parametric analyses that provide useful data for pipeline engineers on the effect of different geometrical parameters on crossover pressure.

Buckle propagation of offshore pipelines under external pressure

2012 ◽  
Vol 29 (1) ◽  
pp. 115-130 ◽  
Author(s):  
Shunfeng Gong ◽  
Bin Sun ◽  
Sheng Bao ◽  
Yong Bai
Keyword(s):  
External Pressure ◽  
Offshore Pipelines ◽  
Buckle Propagation

Efficiency of Carbon Fibre Buckle Arrestors for Subsea Pipelines

2019 ◽  
Author(s):  
Hassan Karampour ◽  
Mahmoud Alrsai ◽  
Wayne Hall
Keyword(s):  
Pressure Gauge ◽  
External Pressure ◽  
Hyperbaric Chamber ◽  
Reinforced Polymer ◽  
Dog Bone ◽  
Buckle Propagation ◽  
Pipeline Wall ◽  
Subsea Pipelines ◽  
Buckle Arrestors ◽  
Hoop Direction

Abstract This paper experimentally investigates the feasibility and efficiency of using Carbon Fiber Reinforced Polymer (CFRP) buckle arrestors in controlling the buckle propagation failure of subsea pipelines. Hyperbaric chamber tests are conducted on 1.6m Steel pipe with D/t = 28 and using CFRP buckle arrestors with different thickness, fiber orientation and spacing. Using an external pressure gauge and a high-pressure camera inserted inside the hyperbaric chamber, the pressure magnitude, rate and shape of collapse and its propagation in the vicinity of the arrestors are measured. The dynamics of buckle propagation and efficiency of different arrestor configurations are reported. It is observed that in the vicinity of the CFRP arrestors wrapped in the hoop direction, the well-known dog-bone buckle shape changes into a U-shape and the pressure level upsurges significantly. The optimum results were obtained with CFRP as thick as the pipeline wall-thickness and wrapped in the hoop direction of the pipeline. The results show that at similar arrestor efficiency, the CFRP arrestors can be much thinner than the existing steel slip-on arrestors. Also, the spacing between the CFRP arrestor can be larger than that of the steel slip-on arrestor.

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.

Buckle Propagation and Its Arrest: Buckle Arrestor Design Versus Numerical Analyses and Experiments

2003 ◽  
Author(s):  
Enrico Torselletti ◽  
Roberto Bruschi ◽  
Furio Marchesani ◽  
Luigino Vitali
Keyword(s):  
Structural Reliability ◽  
External Pressure ◽  
Numerical Analyses ◽  
Potential Hazard ◽  
Line Pipe ◽  
Deep Waters ◽  
Offshore Pipeline ◽  
Reliability Methods ◽  
Buckle Propagation ◽  
Buckle Arrestors

Buckle propagation under external pressure is a potential hazard during offshore pipeline laying in deep waters. It is normal design practice to install thicker pipe sections which, in case of buckle initiation and consequent propagation, can stop it so avoiding the lost of long pipe sections as well as threats to the installation equipment and dedicated personnel. There is still a series of questions the designer needs to answer when a new trunkline for very deep water applications is conceived: • What are the implications of the actual production technology (U-ing, O-ing and Expansion or Compression e.g. UO, UOE and UOC) on the propagation and arrest capacity of the line pipe, • How formulations for buckle arrestors design can be linked to a safety objective as required in modern submarine pipeline applications. The answers influence any decision on thickness, length, material and spacing of buckle arrestors. This paper gives an overview of buckle propagation and arrest phenomena and proposes a new design equation, applicable for both short and long buckle arrestors, based on available literature information and independent numerical analyses. Partial safety factors are recommended, based on a calibration process performed using structural reliability methods. Calibration aimed at fulfilling the safety objectives defined in DNV Offshore Standards OS-F101 and OS-F201.

Propagating Buckle Arrestors for Offshore Pipelines

1978 ◽  
Vol 100 (2) ◽  
pp. 206-214 ◽  
Author(s):  
T. G. Johns ◽  
R. E. Mesloh ◽  
J. E. Sorenson
Keyword(s):  
Experimental Research ◽  
External Pressure ◽  
Offshore Pipelines ◽  
Free Ring ◽  
Underwater Pipeline ◽  
Buckle Arrestors

When an underwater pipeline is buckled in the presence of sufficient external pressure, a propagating buckle is initiated, and the buckle front will propagate along the pipeline until a region of much less external pressure is reached. This paper describes the results of experimental research on methods of arresting the advancement of a propagating buckle along the pipeline. The arresting capacities of three types of buckle arrestors conceived during this program, free-ring, welded-ring, and heavy-walled section arrestors, are described in detail. Results of propagating pressure experiments are also presented.

On the “Slip-On” Buckle Arrestor for Offshore Pipelines

1980 ◽  
Vol 102 (2) ◽  
pp. 188-193 ◽  
Author(s):  
S. Kyriakides ◽  
C. D. Babcock
Keyword(s):  
Experimental Analysis ◽  
Empirical Formula ◽  
Low Pressure ◽  
External Pressure ◽  
Design Criteria ◽  
Offshore Pipelines ◽  
Parametric Dependence ◽  
Dynamic Conditions ◽  
Adverse Conditions

If a pipeline buckles in the presence of sufficiently large external pressure a propagating buckle is initiated. The buckle propagates along the pipeline until it encounters a region of adverse conditions—low pressure or an arresting device. This paper describes a complete experimental analysis of the parametric dependence of the so-called “slip-on” arrestor. An empirical formula is derived for the efficiency of this arrestor. It was also found that quasi-static design criteria underestimate the arrestor efficiency under dynamic conditions. Any gap between the arrestor and the pipe greatly affects the efficiency.

Carbon fibre buckle arrestors for offshore pipelines

2021 ◽  
Vol 111 ◽  
pp. 102633
Author(s):  
Mahmoud Alrsai ◽  
Hassan Karampour ◽  
Wayne Hall ◽  
Alex K. Lindon ◽  
Faris Albermani
Keyword(s):  
Carbon Fibre ◽  
Offshore Pipelines ◽  
Buckle Arrestors
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