The Effect of the Reeling Laying Method on the Collapse Pressure of Steel Pipes for Deepwater

2004 ◽  
Author(s):  
Ilson P. Pasqualino ◽  
Silvia L. Silva ◽  
Segen F. Estefen
Keyword(s):  
Numerical Model ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Element Model ◽  
External Pressure ◽  
Test Facility ◽  
Collapse Pressure ◽  
Steel Pipes ◽  
Custom Made ◽  
Nonlinear Finite Element Model

This work deals with a numerical and experimental investigation on the effect of the reeling installation process on the collapse pressure of API X steel pipes. A three-dimensional nonlinear finite element model was first developed to simulate the bending and straightening process as it occurs during installation. The model is then used to determine the collapse pressures of both intact and plastically strained pipes. In addition, experimental tests on full-scale models were carried out in order to calibrate the numerical model. Pipe specimens are bent on a rigid circular die and then straightened with the aid of a custom-made test facility. Subsequently, the specimens are tested quasi-statically under external pressure until collapse in a pressure vessel. Unreeled specimens were also tested to complete the database for calibrating the numerical model. The numerical model is finally used to generate collapse envelopes of reeled and unreeled pipes with different geometry and material.

Effects of Reeling on Pipe Structural Performance—Part II: Analysis

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Yafei Liu ◽  
Stelios Kyriakides ◽  
Jyan-Ywan Dyau
Keyword(s):  
3D Model ◽  
Kinematic Hardening ◽  
Three Dimensional ◽  
Element Model ◽  
External Pressure ◽  
Structural Performance ◽  
Collapse Pressure ◽  
Reverse Loading ◽  
Tension Loading ◽  
Different Levels

Part II presents two modeling schemes for simulating the reeling/unreeling of a pipeline, with the aim of establishing the degrading effect of the process on the structural performance of the pipeline. A three-dimensional (3D) finite element model of the winding/unwinding of a long section of pipeline onto a rigid reel is presented first. The second model applies the curvature/tension loading history experienced at a point to a section of pipe in contact with a rigid surface of variable curvature. Both models use nonlinear kinematic hardening plasticity to model the loading/reverse loading of the material. The 3D model first demonstrates how the interaction of the problem nonlinearities influences the evolution of deformation and load parameters during reeling/unreeling. The two models are subsequently used to simulate the three-reeling/unreeling cycle experiments under different levels of back tension in Part I. The ovality-tension and axial elongation-tension results are reproduced by both models with accuracy for the first cycle, adequately for the second cycle, and are overpredicted for the third cycle. The two models are also used to simulate the reeling/unreeling followed by collapse of the tubes under external pressure experiments. Both models reproduce the measured ovality-tension results and the corresponding collapse pressures accurately. Since the two-dimensional (2D) model is computationally much more efficient, it is an attractive tool for estimating the effect of reeling on collapse pressure. Questions that require exact tracking of the winding/unwinding history and the interaction of the pipe with the reel are best answered using the 3D model.

Integrity Assessment of Damaged Flexible Pipe Cross-Sections

2014 ◽  
Author(s):  
Guomin Ji ◽  
Bernt J. Leira ◽  
Svein Sævik ◽  
Frank Klæbo ◽  
Gunnar Axelsson ◽  
...  
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Element Model ◽  
Computer Code ◽  
Flexible Pipe ◽  
Dynamic Stresses ◽  
Integrity Assessment ◽  
Residual Capacity ◽  
Nonlinear Finite Element Model

This paper presents results from a case study performed to evaluate the residual capacity of a 6″ flexible pipe when exposed to corrosion damages in the tensile armour. A three-dimensional nonlinear finite element model was developed using the computer code MARC to evaluate the increase in mean and dynamic stresses for a given number of damaged inner tensile armor wires. The study also includes the effect of these damages with respect to the associated stresses in the pressure spiral. Furthermore, the implications of a sequence of wire failures with respect to the accumulated time until cross-section failure in a probabilistic sense are addressed.

scholarly journals Comparative Analysis of Static Loading Performance of Rigid and Flexible Road Wheel based on Finite Element Method

2020 ◽  
Vol 70 (1) ◽  
pp. 41-46
Author(s):  
Yaoji Deng ◽  
Youqun Zhao ◽  
Mingmin Zhu ◽  
Zhen Xiao ◽  
Qiuwei Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Static Loading ◽  
Maximum Stress ◽  
Three Dimensional ◽  
Element Model ◽  
Vertical Load ◽  
New Type ◽  
Stress And Deformation ◽  
Nonlinear Finite Element Model

To overcome the shortcomings of traditional rigid road wheel, such as poor damping effect and low load-bearing efficiency, a new type of flexible road wheel, having a unique suspension-bearing mode, was introduced. The three-dimensional nonlinear finite element model of rigid and flexible road wheel, considering the triple nonlinear characteristics of geometry, material and contact, is established for numerical investigation of static loading performance. The accuracy of the finite element model of the rigid and flexible road wheel is verified by static loading experiment. The static loading performance of the rigid and flexible road wheels is numerically analyzed. The influence of vertical load on maximum stress and deformation of the rigid and flexible wheels is also studied. The results show that the contact pressure uniformity of the flexible road wheel is better than that of the rigid road wheel under the static vertical load, but the maximum stress and deformation of the flexible road wheel are greater than that of the rigid road wheel. However, this problem can be solved by increasing the number of hinge sets and optimising the joints. The research results provide theoretical basis for replacing rigid road wheel with flexible road wheel, and also provide reference for structural optimisation of flexible road wheel.

On the Structural Response of a Flexible Pipe With Damaged Tensile Armor Wires

2011 ◽  
Author(s):  
Jose´ Renato M. de Sousa ◽  
George C. Campello ◽  
Antoˆnio Fernando B. Bueno ◽  
Eduardo Vardaro ◽  
Gilberto B. Ellwanger ◽  
...  
Keyword(s):  
Mechanical Response ◽  
High Stress ◽  
Three Dimensional ◽  
Structural Response ◽  
Experimental Tests ◽  
Element Model ◽  
Axial Stiffness ◽  
Stress Concentrations ◽  
Flexible Pipe ◽  
Flexible Pipes

This paper studies the structural response of a 6.0″ flexible pipe under pure tension considering two different situations: the pipe is intact or has five wires broken in its outer tensile armor. A three-dimensional nonlinear finite element model devoted to analyze the local mechanical response of flexible pipes is employed in this study. This model is capable of representing each wire of the tensile armors and, therefore, localized defects, including total rupture, may be adequately represented. Results from experimental tests are also presented in order to validate the theoretical estimations. The theoretical and experimental results indicate that the imposed damage reduced the axial stiffness of the pipe. High stress concentrations in the wires near the damaged ones were also observed and, furthermore, the stresses in the inner carcass and the pressure armor are affected by the imposed damage, but, on the other hand, the normal stresses in the wires of the inner tensile armor are not.

A Simple Procedure for the Prediction of the Collapse Pressure of Pipelines With Narrow and Long Corrosion Defects: Uncertainty and Sensibility Analysis

2018 ◽  
Author(s):  
Nara Oliveira ◽  
Theodoro Netto
Keyword(s):  
Simple Procedure ◽  
Experimental Tests ◽  
External Pressure ◽  
Experimental Program ◽  
Small Scale ◽  
Test Results ◽  
Collapse Pressure ◽  
Operational Conditions ◽  
Sensibility Analysis ◽  
Corrosion Defects

The collapse pressure of pipelines containing corrosion defects is usually predicted by deterministic methods, either numerically or through empirical formulations. The severity of each individual corrosion defect can be determined by comparing the differential pressure during operation with the estimated collapse pressure. A simple deterministic procedure for estimating the collapse pressure of pipes with narrow and long defects has been recently proposed by Netto (2010). This formulation was based on a combined small-scale experimental program and nonlinear numerical analyses accounting for different materials and defect geometries. However, loads and resistance parameters have uncertainties which define the basic reliability problem. These uncertainties are mailyrelated to the geometric and material parameters of the pipe and the operational conditions. This paper presents additional experimental tests on corroded pipes under external pressure. The collapse pressure calculated using the equation proposed by Netto (2010) is compared with this new set of experiments and also with test results available in open literature. These results are used to estimate the equation uncertainty. Finally, a sensitivity analysis is performed to identify how geometric parameters of the defects influence the reduction of collapse pressure.

Effect of Steel Properties on Buckling Pressure of Corroded Pipelines

2017 ◽  
Vol 898 ◽  
pp. 741-748 ◽  
Author(s):  
Meng Li ◽  
Hong Zhang ◽  
Meng Ying Xia ◽  
Kai Wu ◽  
Jing Tian Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Yield Strength ◽  
Strain Hardening ◽  
Corrosion Damage ◽  
Element Model ◽  
External Pressure ◽  
Strain Hardening Exponent ◽  
The Finite Element Method ◽  
Collapse Pressure ◽  
Steel Properties

Due to the harsh environment for submarine pipelines, corrosion damage of the pipeline steels is inevitable. After the corrosion damage, pipelines are prone to failure and may cause serious consequences. The analysis of the effects of different steel properties on the collapse pressure of pipelines with corrosion defects is of importance for the option of appropriate pipeline and avoiding accidents. Based on the finite element method, the finite element model of the pipeline with defects under external pressure was built. Firstly, the accuracy of the numerical model was validated by comparing with previous experimental results. The effects of yield strength and strain hardening exponent on collapse pressure of pipelines with different sizes of defect were discussed in detail. Results showed that the yield strength and strain hardening exponent have different influences on collapse pressure: the collapse pressure increases with the increasing yield strength, and the collapse pressure decreases with the increasing strain hardening exponent.

Flexible Pipes: Influence of the Pressure Armor in the Wet Collapse Resistance

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Alfredo Gay Neto ◽  
Clóvis de Arruda Martins
Keyword(s):  
Three Dimensional ◽  
External Pressure ◽  
Flexible Pipe ◽  
3D Fem ◽  
Collapse Pressure ◽  
Flexible Pipes ◽  
Polymeric Layer ◽  
Set Up ◽  
3D Finite Element Method ◽  
Ring Approximation

When submitted to high external pressure, flexible pipes may collapse. If the external sheath is damaged, all the external pressure is directly applied on the internal polymeric layer that transmits the loading to the carcass layer, which can fail due to this effect, leading to wet collapse. This failure mode must be taken into account in a flexible pipe design. A model can be set up neglecting the influence of the pressure armor, but this assumption may underestimate the wet collapse pressure value. This work aims to include the pressure armor effect in the numerical prediction of wet collapse. The main contribution of the pressure armor to the flexible pipe resistance to collapse is to be a constraint to the radial displacement of the carcass and the internal polymeric layers. Two models were developed to find the wet collapse pressure in flexible pipes. A first study was done using a ring approximation three-dimensional (3D) finite element method (FEM) model. Comparisons are made with more simplified models using a 3D FEM equivalent ring approximation. The aim is to clarify the mechanical behavior of the pressure armor in the wet collapse scenario. Parametric studies of initial ovalization of carcass and initial gaps and interference between polymeric layer and pressure armor are made and discussed.

Propagation of Buckles in Sandwich Pipes Under External Pressure

2005 ◽  
Author(s):  
I. P. Pasqualino ◽  
M. I. Lourenc¸o ◽  
T. A. Netto
Keyword(s):  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Element Model ◽  
External Pressure ◽  
Core Material ◽  
Small Scale ◽  
Ongoing Research ◽  
Scale Models ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Sandwich pipes have been considered feasible conceptions for ultra deepwater pipelines, since they are capable to work at low temperatures and withstand high hydrostatic pressures. Sandwich pipelines are composed by inner and outer metallic pipes and a suitable core material which must provide high compression strength and good thermal insulation. The aim of this ongoing research is to study the quasi-static propagation of buckles in sandwich pipes. In this paper, a three-dimensional finite element model considering material and geometric nonlinear behavior is presented. The mesh discretization is determined through a detailed mesh sensitivity analysis. Some experiments with small scale models combining aluminum pipes and polypropylene as core material were carried out to calibrate the numerical model. The propagation pressure is evaluated under different bonding conditions between pipe layers.

Analysis of Mechanical Response for Subgrade of Tramcar with Monolithic Track-Bed

2013 ◽  
Vol 361-363 ◽  
pp. 1765-1771
Author(s):  
Chong Wei Huang ◽  
Shuo Wang ◽  
Xian Zhi Shao ◽  
Xian Zhao Du ◽  
Er Hao Su
Keyword(s):  
Decision Making ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Element Model ◽  
Nonlinear Finite Element ◽  
Track Structure ◽  
Concept Design ◽  
Theoretical Support ◽  
Design Basis ◽  
Nonlinear Finite Element Model

Based on the differences between the subgrade of tramcar with monolithic track-bed and the existing subgrade of railway, anew three-dimensional nonlinear finite element model is established in this paper. And then,the numerical analyses are conducted by considering weight load of track structure. The characteristics of mechanical response in the subgrade of tramcar with monolithic track-bed are found by finite analysis, which offers a reference for the future engineering, in terms of the design concept, design basis and theoretical support as well as the basis for decision making.

Numerical Analysis of a Flexible Pipe With Damaged Tensile Armor Wires

2009 ◽  
Author(s):  
Jose´ Renato M. de Sousa ◽  
Aline Nacif Pinho ◽  
Gilberto Bruno Ellwanger ◽  
Edison C. P. Lima
Keyword(s):  
Mechanical Response ◽  
High Stress ◽  
Three Dimensional ◽  
Element Model ◽  
Axial Rotation ◽  
Flexible Pipe ◽  
High Stress Concentration ◽  
Flexible Pipes ◽  
Localized Defects ◽  
Nonlinear Finite Element Model

This paper focus on the structural analysis of a 2.5″ flexible pipe with one up to five broken wires in its outer tensile armor. The pipe is supposed to be under pure tension and the effect of the number of ruptured wires on its response is discussed. A three-dimensional nonlinear finite element model devoted to analyze the local mechanical response of flexible pipes is proposed and employed in all performed analyses. This model is capable of representing each wire of the tensile armors and, therefore, localized defects, including total rupture, may be adequately represented. The obtained results pointed to high stress concentration in the wires near the damaged ones as well as a significant increase in the axial rotation of the pipe. Moreover, the stresses in the inner carcass and the pressure armor are also affected by the rupture of wires in the outer tensile armor.

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