Comparative Study on the Collapse Response of Flexible Pipe Using Finite Element Methods

2014 ◽  
Author(s):  
Nathan Cooke ◽  
Shawn Kenny
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Numerical Data ◽  
External Pressure ◽  
Operating Conditions ◽  
Combined Loading ◽  
Flexible Pipe ◽  
Geometric Imperfection ◽  
Pipe System ◽  
Pipe Systems

Although the scope and use of flexible pipe systems in deepwater developments is expanding, the mechanical behavior for these environments is not fully understood. This is due to the complex response and interaction between multiple layers within the pipe system that introduces significant difficulties and constraints into the engineering analysis. As future developments look to extend the use of this technology to greater water depths and harsher operating conditions there is a need to develop advanced numerical tools that can evaluate the mechanical integrity of these complex hybrid pipe systems. Availability of increasingly advanced computational packages has enabled substantial improvements to be made in the complexity of simulation tools for combined loading, external pressure collapse and fretting. This study establishes a foundation for the development of advanced numerical modeling procedures to assess the collapse failure of composite flexible pipe systems for deepwater applications. Here, a continuum finite element model is constructed using the software package ABAQUS/Standard, and studied using non-linear (arc length) methods. The carcass, pressure armor and corresponding polymer layers are represented in detail and modeled with three dimensional solid brick elements in order to examine the interlayer relationships influencing collapse initiation. In many recent studies, an initial geometric imperfection in the form of general ovality is explored as the predominant bifurcation mode. A similar approach is adopted here, coupled with case studies chosen such as to facilitate validation against existing analytical and numerical data. The importance of element selection, contact mechanics, interface properties and initial imperfections on the system mechanical response and performance is presented and compared to the available literature.

Assessment of Parameters Influencing Mechanical Response of Constrained and Unconstrained Dents Using Finite Element Modelling

2013 ◽  
Author(s):  
W. Hanif ◽  
S. Kenny
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Mechanical Damage ◽  
Numerical Data ◽  
Performance Criterion ◽  
Metal Loss ◽  
Data Sets ◽  
External Interference ◽  
Seismic Fault ◽  
Girth Welds

Pipelines may experience damage (e.g. dent, gouge) during handling, installation and normal operations due to external interference. Pipelines in offshore environment may be prone to mechanical damage from events such as ice gouging, frost heave, and seismic fault movement. Damage mechanisms can be associated with deformation or metallurgical/metal loss that may include pipe dent, pipe ovality, ice gouging, pipe buckling, corrosion etc. The type and severity of pipe damage may influence operational, repair and intervention strategies. For conventional pipelines, the assessment of mechanical damage plays an important role in the development of integrity management programs that may be of greater significance for pipeline systems located in remote harsh environments due to remote location and logistical constraints. This study examines the effects of plain dents on pipe mechanical response using continuum finite element methods. ABAQUS/Standard (6.10-1) environment was used to simulate damage events and pipe response. Modelling procedures were developed and calibrated against physical and numerical data sets available in public domain. Once confidence in numerical procedures was achieved, an analysis matrix was established to account for a range of influential parameters including Diameter to wall thickness ratio (D/t), indenter diameter to pipe diameter ratio (ID/OD), hoop stress due to internal pressure to yield strength ratio (σh/σy), and kinematic boundary conditions. The results from this study provide a basis to support a broader initiative for developing an engineering tool for the assessment of damage interaction with pipeline girth welds and development of an engineering performance criterion.

scholarly journals Bending of Symmetric Sandwich FGM Beams with Shear Connectors

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Dung Nguyen Thai ◽  
Phung Van Minh ◽  
Cuong Phan Hoang ◽  
Tam Ta Duc ◽  
Nhung Nguyen Thi Cam ◽  
...  
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Volume Fraction ◽  
Beam Theory ◽  
Numerical Data ◽  
Functionally Graded ◽  
Engineering Practice ◽  
Graded Materials ◽  
Shear Connectors ◽  
The Impact

This paper carries out the static bending analysis of symmetric three-layer functionally graded sandwich beams, in which each layer is made from different functionally graded materials, and they are connected by shear connectors due to sliding movement. The finite element formulations are based on Timoshenko’s first-order shear deformation beam theory (FSDT) and the finite element method to establish the equilibrium equation of beams. The calculation program is coded in the MATLAB environment, and then verification examples are given out to compare the numerical data of present work with those of exact open sources. The impact of several geometrical and material parameters on the mechanical response of the structure, such as the height-to-length ratio, boundary conditions, volume fraction index, and especially the shear coefficient of connectors, is being explored. When designing and using these types of structures in engineering practice, the computed results can be utilized as a valid reference.

Finite Element Investigation on the Tensile Armor Wire Response of Flexible Pipe for Axisymmetric Loading Conditions Using an Implicit Solver

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Alireza Ebrahimi ◽  
Shawn Kenny ◽  
Amgad Hussein
Keyword(s):  
Finite Element ◽  
Oil And Gas ◽  
Mechanical Response ◽  
Numerical Models ◽  
Oil And Gas Industry ◽  
Parameter Study ◽  
Loading Conditions ◽  
Flexible Pipe ◽  
Axisymmetric Loading ◽  
Implicit Solver

Composite flexible pipe is used in the offshore oil and gas industry for the transport of hydrocarbons, jumpers connecting subsea infrastructure, and risers with surface platforms and facilities. Although the material fabrication costs are high, there are technical advantages with respect to installation and performance envelope (e.g., fatigue). Flexible pipe has a complex, composite section with each layer addressing a specific function (e.g., pressure containment, and axial load). Continuum finite element modeling (FEM) procedures are developed to examine the mechanical response of an unbonded flexible pipe subject to axisymmetric loading conditions. A parameter study examined the effects of: (1) pure torsion, (2) interlayer friction factor, (3) axial tension, and (4) external and internal pressure on the pipe mechanical response. The results demonstrated a coupled global-local mechanism with a bifurcation path for positive angles of twist relative to the tensile armor wire pitch angle. These results indicated that idealized analytical- and structural-based numerical models may be incomplete or may provide an accurate prediction of the pipe mechanical response. The importance of using an implicit solver to predict the bifurcation response and simulate contact mechanics between layers was highlighted.

Full-Scale Wrinkling Tests and Analyses of Large Diameter Corroded Pipes

1998 ◽  
Author(s):  
Marina Q. Smith ◽  
Daniel P. Nicolella ◽  
Christopher J. Waldhart
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Axial Compression ◽  
Wall Thickness ◽  
Full Scale ◽  
Operating Conditions ◽  
Material Behavior ◽  
Combined Loading ◽  
Longitudinal Bending ◽  
Full Scale Tests

The aging of pipeline infrastructures has increased concern for the integrity of pipelines exhibiting non-perforating wall loss and settlement induced bending. While pressure based guidelines exist which allow pipeline operators to define operational margins of safety against rupture (e.g.; ANSI/ASME B31-G and RSTRENG (Battelle, 1989)), reliable procedures for the prediction of wrinkling in degraded pipes subjected to combined loading are virtually non-existent. This paper describes full-scale testing and finite element investigations performed in support of the development of accurate wrinkling prediction procedures for the Alyeska Pipeline Service Company. The procedures are applicable to corroded pipes subjected to combined loading such as longitudinal bending, internal pressure, and axial compression. During the test program, full-scale 48-inch diameter sections of the trans-Alaska pipeline were subjected to internal pressure and loads designed to simulate longitudinal bending from settlement, axial compression from the transport of hot oil, and the axial restraint present in buried pipe. Load magnitudes were designed based on normal and maximum operating conditions. Corrosion in the pipe section is simulated by mechanically reducing the wall thickness of the pipe. The size and depth of the thinned region is defined prior to each test, and attempts to bound the dimensions of depth, axial length, and hoop length for the general corrosion observed in-service. The analytical program utilizes finite element analyses that include the nonlinear anisotropic material behavior of the pipe steel through use of a multilinear kinematic hardening plasticity model. As in the tests, corrosion is simulated in the analyses by a section of reduced wall thickness, and loads and boundary constraints applied to the numerical model exactly emulate those applied in the full-scale tests. Verification of the model accuracy is established through a critical comparison of the simulated pipe structural behavior and the full-scale tests. Results of the comparisons show good correlation with measurements of the pipe curvature, deflections, and moment capacity at wrinkling. The validated analysis procedure is subsequently used to conduct parameter studies, the results of which complete a database of wrinkling conditions for a variety of corrosion sizes and loading conditions.

Strength of Reinforced Concrete Chambers Under External Pressure

1975 ◽  
Vol 97 (4) ◽  
pp. 309-314 ◽  
Author(s):  
O. Buyukozturk ◽  
P. V. Marcal
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Special Reference ◽  
External Pressure ◽  
General Purpose ◽  
The Finite Element Method ◽  
Cylindrical Tank ◽  
Geometric Imperfection ◽  
Cylindrical Tanks

A study was made to establish the strength of concrete chambers subjected to external pressure with special reference to the reinforced concrete cylindrical tanks. The finite element method as implemented in a nonlinear general purpose program produced analytical results which agreed with the experiment. The study concluded that the cylindrical tank was weakened in buckling by 20 percent due to geometric imperfection, 10 percent due to creep and 6 percent due to reinforcements. The main failure mode of the shell was compression shear.

Experimental and Numerical Analysis of Read/Write Head Suspension Dynamics for High-Performance Floppy Drive Systems

1990 ◽  
Vol 112 (1) ◽  
pp. 26-32 ◽  
Author(s):  
G. M. Frees ◽  
D. K. Miu
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
High Performance ◽  
Laser Doppler Vibrometer ◽  
Numerical Data ◽  
Floppy Disk ◽  
Element Model ◽  
Operating Conditions ◽  
Tracking Performance ◽  
Mode Shapes

Read/write head suspensions are critical components of high-performance floppy disk drives. Their dynamics affect head/media compliance, wear, and tracking performance. Vibration measurements are necessary in order to verify and adjust finite element models, to observe the influence of actual loading and operating conditions, and to study the effects of unmodeled components such as electrical wires and adhesives. A nonintrusive measurement technique using a Laser Doppler Vibrometer is utilized to measure the submicron vibrations. Excitation of the suspension is provided by a specially designed miniature air hammer and a piezoelectric transducer. Natural frequencies and mode shapes are extracted from the measurements and compared with numerical data from the finite element model. Research shows that boundary conditions are the most important parameters in the modeling of the suspension. A new design is proposed, using the verified model, to increase the tracking performance of the suspension. Synergy between experimentation and numerical analysis is emphasized.

A Proposed Strategy for Risk Analysis of Flexible Pipe Systems

2010 ◽  
Author(s):  
Carlos Eduardo Costa Valle Longo ◽  
Guilherme de Salles Bessa ◽  
Marcelo Brack ◽  
Ota´vio Campos de Arau´jo ◽  
Wallace Bartholomeu e Silva
Keyword(s):  
Risk Analysis ◽  
Oil And Gas ◽  
Flexible Pipe ◽  
Pipe System ◽  
Previous Definition ◽  
Integrity Management ◽  
Historic Data ◽  
Potential Failure ◽  
Pipe Systems ◽  
Definition Of

Nowadays, due to the increasing importance of the HSE and also the operational availability requirements, one of the most important challenges for producing oil and gas at subsea environments is to have a mature methodology for quantifying risks. The main objective of this paper is to present a strategy for running risk analysis of flexible pipe systems. These systems are extensively used by Petrobras to flow different kinds of fluids in deep water offshore scenarios. The strategy presented herein includes the classification of threats and the potential failure mechanisms. Probabilistic figures are established depending on the historic data of the components of the flexible pipe system and also on the theoretical results obtained from available models for determination of the component remaining life. The strategy is based on the previous definition of inference rules and technical criteria for probability, consequence and risk assessments. The final goal is to have an adequate tool to help Operators to take decisions, to establish strategies and to improve flexible pipe integrity management.

scholarly journals Finite Element Simulation for Structural Response of U7Mo Dispersion Fuel Plates via Fluid-Thermal-Structural Interaction

2010 ◽  
Author(s):  
Hakan Ozaltun ◽  
Herman Shen ◽  
Pavel Medvedev
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Aluminum Matrix ◽  
Structural Response ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Fe Model ◽  
Structural Interaction ◽  
Dispersion Fuel ◽  
Sem Image

This article presents numerical simulation of dispersion fuel mini plates via fluid-thermal-structural interaction performed by commercial finite element solver COMSOL Multiphysics to identify initial mechanical response under actual operating conditions. Since fuel particles are dispersed in Aluminum matrix, and temperatures during the fabrication process reach to the melting temperature of the Aluminum matrix, stress/strain characteristics of the domain cannot be reproduced by using simplified models and assumptions. Therefore, fabrication induced stresses were considered and simulated via image based modeling techniques with the consideration of the high temperature material data. In order to identify the residuals over the U7Mo particles and the Aluminum matrix, a representative SEM image was employed to construct a microstructure based thermo-elasto-plastic FE model. Once residuals and plastic strains were identified in micro-scale, solution was used as initial condition for subsequent multiphysics simulations at the continuum level. Furthermore, since solid, thermal and fluid properties are temperature dependent and temperature field is a function of the velocity field of the coolant, coupled multi-physics simulations were considered. First, velocity and pressure fields of the coolant were computed via fluid-structural interaction. Computed solution for velocity fields were used to identify the temperature distribution on the coolant and on the fuel plate via fluid-thermal interaction. Finally, temperature fields and residual stresses were used to obtain the stress field of the plates via fluid-thermal-structural interaction.

Mechanical Analysis of Fiber Glass Reinforced Bonded Flexible Pipe Under External Pressure

2019 ◽  
Author(s):  
Xiaojie Zhang ◽  
Yong Bai ◽  
Chang Liu ◽  
Zhao Wang ◽  
Jiannan Zhao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Method ◽  
Cross Section ◽  
Mechanical Analysis ◽  
External Pressure ◽  
Fiber Glass ◽  
Flexible Pipe ◽  
Pressure Test ◽  
Element Method

Abstract Fiber glass reinforced bonded flexible pipe (FGRFP) is one kind of new type composite pipe. However, the mechanical properties of FGRFP are not so clearly at present. Therefore, this article aims at studying the buckling pressure of FGRFP under external pressure by using external pressure test, numerical method and finite element method. Three kinds of buckling pressure have been obtained by using three methods as aforesaid. According to compare the buckling pressure of three methods, the relative error of the numerical method and the finite element method relative to external pressure test ranges from 4.09% to 14.51%. According to the result of finite element method, the first layer’s stress at the topside of FGRFP’s cross section and the final layer’s stress at the horizontal position of FGRFP’s cross section is the max stress. The numerical method and finite element method came up with in this article can be used to analyze the buckling pressure of FGRFP. These methods can also provide a guidance to pipeline engineers to design and production of FGRFP.

Simplified Finite Element Models to Study the Wet Collapse of Straight and Curved Flexible Pipes

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Alfredo Gay Neto ◽  
Clóvis de Arruda Martins ◽  
Eduardo Ribeiro Malta ◽  
Rafael Loureiro Tanaka ◽  
Carlos Alberto Ferreira Godinho
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
3D Models ◽  
External Pressure ◽  
Finite Element Models ◽  
Flexible Pipe ◽  
Collapse Pressure ◽  
Flexible Pipes ◽  
Polymeric Layer ◽  
Collapse Failure

When the external sheath of flexible pipes experiences damage, seawater floods the annulus. Then, the external pressure is applied directly on the internal polymeric layer, and the load is transferred to the interlocked carcass, the innermost layer. In this situation, the so-called wet collapse failure of the interlocked carcass can occur. Simplified methodologies to address such a scenario, using restricted three-dimensional (3D) finite element models, are presented in this work. They are compared with full 3D models, studying both straight and curved flexible pipes scenarios. The curvature of the flexible pipe is shown to be important for wet collapse pressure predictions.

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