## What is/are Flexible Pipes?

Flexible Pipes - Thus, the estimation of the bending cycles number to initiate buckling is favorable to prevent buckling failure and enlarge the potential application scope of flexible pipes.^{[1]}It is also expected, in the near future, to extend the basic idea of this work to explore the nonlinear responses of flexible pipes and hoses conveying fluid subjected rigid stops by introducing a multi-segment articulated pipe model.

^{[2]}Flexible Pipes were widely used in Brazil offshore developments and the challenge on overcoming increasing water depths, high pressures and fluids with high contaminants was always present.

^{[3]}As offshore oil and gas exploration takes place at greater depths, so more flexible pipes are failing by collapsing.

^{[4]}Flexible pipes are critical elements for offshore oil and gas development and determining its response in axisymmetric loadings is of paramount importance.

^{[5]}The function of flexible pipes with a large deformation requirement in the isolation layer is critical, but the fragility model and consequence functions of such pipes were rarely reported, which hinders the seismic resilience assessment of isolated structures.

^{[6]}Collapse bucking is a typical failure mode of flexible pipes during deepwater service.

^{[7]}The investigated steels were armor wires for flexible pipes.

^{[8]}Large strain deformation theory is used to analyze the effects of high pressure-high temperature two-phase flow on critical velocity in flexible pipes.

^{[9]}In recent years a number of high-profile cases have shown that flexible pipes are particularly susceptible to the aggressive environments occasionally found in deep-water oil and gas exploration.

^{[10]}In this article, we present the elements of a numerical multiscale procedure capable of predicting the stresses that lead to fatigue damage in flexible pipes, namely: a nonlinear beam element, a nonlinear section response model and a detailed finite element model; the consistent integration of models developed for different length scales; and finally a validation of the flexible riser large-scale model.

^{[11]}Diameters and wall thicknesses of flexible pipes are usually designed as per hydraulic requirements, such as flow capacity, internal fluid pressure, and pipe material properties.

^{[12]}The purpose of this study was to analyze the head loss in flexible pipes with laser-perforated orifices, and to estimate the maximum length of laterals based on criteria of water distribution uniformity.

^{[13]}Structural Analysis of Flexible Pipes and Umbilical Cables: a bimaterial Finite Element modeling technique and a novel experimental approach using a Digital Image Correlation system.

^{[14]}Theoretical studies have substantiated a rational correlation of diameters of tubing, columns of flexible pipes and the flow rate of the flushing agent for washing the sand plug in the wells with various flushing agents.

^{[15]}In the structural analysis of flexible pipes, the Finite Element Method (FEM) stands as a powerful and widespread tool.

^{[16]}In addition, some useful suggestions for improving the design of flexible pipes against the armor wires lateral instability failure are presented.

^{[17]}In addition, the fluid–structure interaction of compressible fluid flowing in flexible pipes is also considered.

^{[18]}The present paper addresses armor wire lateral instability in flexible pipes and umbilicals.

^{[19]}A novel generation of irrigation systems was introduced on the basis of hydrophilic, swellable, permeable, soft and flexible pipes using polymeric hydrogels.

^{[20]}This paper proposes a finite element (FE) modal approach to determine the critical loads and buckling mode shapes associated with the lateral buckling of the tensile armors in flexible pipes.

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## Unbonded Flexible Pipes

This paper presents a method to predict the bending hysteretic behavior of unbonded flexible pipes using full layered numerical general finite element models with an implicit solver.^{[1]}Unbonded flexible pipes are widely utilized in the exploitation of offshore oil and gas resources.

^{[2]}An analytical model is proposed to investigate the local torsion and bending behavior of tensile armors in unbonded flexible pipes.

^{[3]}Unbonded flexible pipes have superior fatigue performance as the internal armor layers are allowed to move relative to each other, leading to reduced structural loading.

^{[4]}Unbonded flexible pipes consist of multiple subcomponents which interact through frictional contact.

^{[5]}Unbonded flexible pipes have become widely employed in marine environments with the development of the offshore oil and gas exploration industry.

^{[6]}Three kinds of models based on the same flexible pipe with 8 layers have been separately created to investigate the effects of different modeling approaches on numerical simulation results of finite element (FE) models for unbonded flexible pipes.

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## Strip Flexible Pipes

Metallic strip flexible pipes (MSFP), a relatively new style of unbonded flexible pipes, are considered as an attractive alternative to traditional submarine pipes.^{[1]}Metallic strip flexible pipes (MSFP), a relatively new style of unbonded flexible pipes, are considered as an attractive alternative to traditional submarine pipes.

^{[2]}Moreover, this work answers a question raised by producers that need to know when tensile armor is required to reinforce Metallic Strip Flexible Pipes (MSFP).

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## Buried Flexible Pipes

This paper investigates an experimental study on reducing stress acting on buried flexible pipes by using expanded polystyrene (EPS) geofoam techniques.^{[1]}The earthquake shake has a significant impact on the response of buried infrastructures; however, no study has been conducted on the behavior of buried flexible pipes subjected to earthquake shake.

^{[2]}In this study, stress analyses of buried flexible pipes were carried out using a newly designed experimental setup for the method of photoelasticity.

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## Bonded Flexible Pipes

In this paper, a simplified model for erosion in un-bonded flexible pipes caused by the sand entrained in the produced fluid is established.^{[1]}ABSTRACT Fibreglass reinforced flexible pipe (FGRFP) is regarded as a great alternative to bonded flexible pipes in the field of oil or gas transportation.

^{[2]}Marine un-bonded flexible pipes wrapped with fiber-reinforced polymer are essential in offshore oil and gas exploration because of their high flexibility and reliability.

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## Two Flexible Pipes

The behaviours of these two flexible pipes were tested using a 3D finite element (FE) model, validated against experimental data from a laboratory investigation.^{[1]}However, when comparing the two flexible pipes in this study, despite no significant differences in cell shape anisotropy were found, a significantly different behaviour for the E modulus ratio was observed.

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## flexible pipes consist

Tensile armor in flexible pipes consists of two or more layers of steel wires.^{[1]}Unbonded flexible pipes consist of multiple subcomponents which interact through frictional contact.

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## flexible pipes subjected

The calculation of stress components in tensile armour wires of flexible pipes subjected to combined tension and bending is challenging given the intrinsic geometrical and physical nonlinearities.^{[1]}The earthquake shake has a significant impact on the response of buried infrastructures; however, no study has been conducted on the behavior of buried flexible pipes subjected to earthquake shake.

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