Strength Analyses of Sandwich Pipes for Ultra Deepwaters

Estefen, Segen F.; Netto, Theodoro Antoun; Pasqualino, Ilson Paranhos

doi:10.1115/1.1940667

Cited by 67 publications

(19 citation statements)

References 14 publications

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“…Substituting Eqs. (13)- (15) into (12), the propagation pressure, P p2 , of the PIP system is obtained as:…”

Section: Analytical Solution Of Propagation Pressure Of Pipe-in-pipe mentioning

confidence: 99%

“…The work done by Xue et al [9] investigates the effect of corrosion in the propagation buckling of subsea pipelines. Buckle arrestors [1,18], pipe-in-pipe system [10][11][12][13][14], sandwich pipe system [15] and ring-stiffened pipelines [16], are used to confine the propagation buckling in subsea pipelines.…”

Section: Propagation Buckling Of Single Pipe 11 Introductionmentioning

confidence: 99%

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Propagation Buckling of Subsea Pipelines and Pipe-in-Pipe Systems

Karampour¹,

Alrsai²

2020

New Innovations in Engineering Education and Naval Engineering

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This chapter investigates buckle propagation of subsea single-walled pipeline and pipe-in-pipe (PIP) systems under hydrostatic pressure, using 2D analytical solutions, hyperbaric chamber tests and 3D FE analyses. Experimental results are presented using hyperbaric chamber tests, and are compared with a modified analytical solution and with numerical results using finite element analysis for single-walled pipelines and PIPs. The experimental investigation is conducted using commercial aluminum tubes with diameter-to-thickness (D/t) ratio in the range 20-48. The comparison indicates that the modified analytical expression presented in this work provides a more accurate lower bound estimate of the propagation buckling pressure of PIPs compared to the existing equations, especially for higher D o /t o ratios. A 3D FE model is developed and is validated against the experimental results of the propagation bucking. A parametric FE study is carried out and empirical expressions are provided for buckle propagation pressures of PIPs with (D o /t o) ratio in the range 15-25. Moreover, empirical expressions are proposed for the collapse pressure of the inner pipe (P ci), the proposed empirical equation for P ci , is shown to agree well with the experimental results of the tested PIPs.

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“…Substituting Eqs. (13)- (15) into (12), the propagation pressure, P p2 , of the PIP system is obtained as:…”

Section: Analytical Solution Of Propagation Pressure Of Pipe-in-pipe mentioning

confidence: 99%

Section: Propagation Buckling Of Single Pipe 11 Introductionmentioning

confidence: 99%

Propagation Buckling of Subsea Pipelines and Pipe-in-Pipe Systems

Karampour¹,

Alrsai²

2020

New Innovations in Engineering Education and Naval Engineering

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“…The model employed in this work is similar to those from Estefen et al (2005), which were validated with small-scale experimental tests. The collapse curvature corresponds to the maximum moment reaction at the reference node.…”

Section: Numerical Model For Combined Loadingmentioning

confidence: 99%

“…The objective of this type of pipe is to increase the thermal insulation capacity to prevent blockage of the line caused by dropping fluid temperature below that required to form paraffin or hydrate. Numerical and experimental studies carried out by Estefen et al (2005) for the ultimate strength under combined external pressure and bending indicated that SP is viable for application in water depths up to 3,000 meters. In the case of SP, object of this study, the annular layer characteristics differ from PIP by satisfying simultaneously mechanical and thermal requirements.…”

Section: Introductionmentioning

confidence: 99%

Sandwich Pipes for Ultra Deepwater Applications

Castello

Estefen

2008

All Days

Self Cite

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Ultra deepwater scenarios, related to water depths beyond 1,500 m, require very thick walled steel pipelines or pipe-in-pipe systems, which are expensive and difficult to install due to excessive weight. Sandwich pipe is a new concept composed of two concentric steel pipes separated by and bonded to a polymeric annulus that provide the combination of high structural strength with thermal insulation. Previous results indicate that collapse pressure is strongly dependent on the polymer stiffness. The adhesion property is also important and can affect significantly the pipeline external pressure resistance due to the relative displacement between layers. Sandwich pipes can minimize steel costs and facilitate the ultra deepwater installation, with thermal and structural performance close to pipe-in-pipe systems. In this work, experimental tests and numerical models are employed to verify the influence of the inter-layer adhesion on the ultimate strength under external pressure and longitudinal bending of a sandwich pipe prototype. The maximum shear stress obtained from sandwich pipe specimens bonded by a particular adhesive indicated the adhesion levels to be adopted in the numerical simulations. Contact model combined with non-linear springs that connect the steel pipes to the polymer layer was employed to analyze both bonding and slipping conditions. As expected for a sandwich structure, the strength is strongly dependent on the interface stickiness. The analyzed geometry is able to withstand a water depth up to 3,000 meters with a bonding strength corresponding to only 10% of the idealized perfect adhesion condition. Finally, sandwich pipes with typical inner diameters of those employed in the offshore production are analyzed numerically to evaluate the ultimate strength under external pressure. The annular material must have both adequate mechanical strength and low thermal conductivity properties to satisfy the operational requirements. Some polymeric materials with different properties are selected. The global heat transfer coefficient is determined in each case to attend the thermal insulation requirements of an oil field.

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“…Sato and Patel [2007] and Sato et al [2008] studied the buckling behavior of a PIP system under hydrostatic pressure and developed a simplified solution for estimating a PIP system's buckling capacity. Castello and Estefen [2006; and Estefen et al [2005] studied the feasibility of a sandwich pipe system for deep water applications with both numerical and experimental approaches. In another study, Castello and Estefen [2007] investigated the ultimate strength of sandwich pipes under combined external pressure and bending for several degrees of adhesion between the core layer and outer pipe.…”

Section: Introductionmentioning

confidence: 99%

Elastic buckling capacity of bonded and unbonded sandwich pipes under external hydrostatic pressure

Arjomandi

Taheri‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬

2010

JoMMS

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Sandwich pipes can be a potentially optimal system for use in deep-water applications. In recent years, there has been considerable interest in understanding the stability characteristics of these pipes under the governing loading conditions, with the aim of generating optimal design. External hydrostatic pressure is a critical loading condition that a submerged pipeline experiences during its installation and operational period.This article presents an analytical approach for estimating the bucking capacity of sandwich pipes with various structural configurations and core materials, subject to external hydrostatic pressure. The influence of adhesion between the core layer and inner or outer pipes is also a focus of this study. Beside the exact solution, two simplified equations are developed for estimating the buckling capacity of two configurations commonly used in practice. Details of both the exact and simplified analytical formulations are presented and the required parameters are defined. The efficiency and integrity of the proposed simplified solutions are compared with a solution developed by other researchers. A comprehensive series of finite element eigenvalue buckling analyses was also conducted to evaluate the accuracy and applicability of the proposed solutions.

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Strength Analyses of Sandwich Pipes for Ultra Deepwaters

Cited by 67 publications

References 14 publications

Propagation Buckling of Subsea Pipelines and Pipe-in-Pipe Systems

Propagation Buckling of Subsea Pipelines and Pipe-in-Pipe Systems

Sandwich Pipes for Ultra Deepwater Applications

Elastic buckling capacity of bonded and unbonded sandwich pipes under external hydrostatic pressure

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