Enhanced Collapse Resistance of Compressed Steel Pipes

2014 ◽  
Author(s):  
Venkat R. Krishnan ◽  
David A. Baker
Keyword(s):  
Experimental Testing ◽  
Three Dimensional ◽  
External Pressure ◽  
Combined Loading ◽  
Finite Element Analyses ◽  
Forming Process ◽  
3D Finite Element ◽  
Steel Pipes ◽  
Collapse Resistance ◽  
Sensitivity Studies

Pipe collapse is a primary design consideration for deep water locations and offshore areas with sharp seabed curvatures or spans, where bending reduces collapse resistance due to ovalization. Previous numerical and experimental work has shown that collapse resistance of steel pipes can be enhanced significantly by using compression instead of expansion during the final stage of the pipe forming process. ExxonMobil has recently undertaken a rigorous numerical modeling and experimental testing program to investigate the collapse resistance of compressed (JCOC) steel pipes under combined loading of external pressure and bending, and this paper presents the main results from the program. The first part of the paper presents results of sensitivity studies from three dimensional (3D) finite element analyses (FEA) of the pipe forming process, and the second part focuses on the collapse modeling under combined loading as well as a comparison of the numerical results with the experiments. The results indicate that the collapse envelope for steel pipes under combined external pressure and bending can be enhanced by up to 35% by adopting pipe compression rather than expansion as the final step of the forming process.

Numerical and Experimental Analysis for Large Radius Deformation of Stainless Steels by Laser Forming Process

2005 ◽  
Author(s):  
J. Pennuto ◽  
J. Choi
Keyword(s):  
Experimental Data ◽  
Phase Transformation ◽  
Experimental Testing ◽  
Three Dimensional ◽  
Laser Forming ◽  
Bend Angle ◽  
Large Radius ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Forming Process

In an effort to develop a process free of dedicated tooling, this research seeks to study large radius deformation by laser forming. Experimental testing was conducted to determine how the laser parameters affect the single pass output bend angle as well as the additive bend angle from successive parallel, evenly spaced laser irradiations. As an extension of the previous developments, this work seeks to develop a three-dimensional model to simulate the multi-scan laser process. It is of interest to determine how sophisticated a three-dimensional case is required for sufficient agreement to experimental data. The simulated results of bending angle are compared with experimental data and suggestions for future study include the implementation of phase transformation and microstructure data within the model to account for stress development resulting from phase transformation and grain growth.

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.

Modeling of the Collapse and Propagation Behavior of UOE SAW Pipes Under External Pressure: Influence of Thermal Treatments for Typical Coating Applications

2012 ◽  
Author(s):  
Luciano O. Mantovano ◽  
Santiago Serebrinsky ◽  
Hugo A. Ernst ◽  
Teresa Perez ◽  
Martin Valdez ◽  
...  
Keyword(s):  
Finite Element ◽  
Experimental Testing ◽  
Large Diameter ◽  
Model Development ◽  
External Pressure ◽  
Sensitivity Analyses ◽  
Thermal Treatments ◽  
Collapse Pressure ◽  
Collapse Resistance ◽  
Comparison Of The Results

Large diameter UOE pipes are being increasingly used for the construction of offshore pipelines. Since oil discoveries are moving towards ultra deep water areas, collapse resistance is a key factor in the design of the pipelines. It has been demonstrated in previous works that the application of typical coating thermal treatments increases the collapse resistance of the pipes recovering the original strength of the plate. To improve the understanding of these effects, the Tenaris has embarked on a program of both, experimental testing and finite element modeling. Previous phases of this work formulated the basis for model development and described the 2D approach taken to model the various stages of manufacture, from the plate to the final pipe and the collapse test. More recent developments included some modeling enhancements, sensitivity analyses, and comparison of predictions to the results of full scale collapse testing. In the present work, 3D finite element analyses of collapse were performed and compared with the latest collapse and propagation tests performed by Tenaris, where the effect of typical coating thermal treatments was studied and significant increments in the collapse pressure of pipes were obtained. The numerical results show a good agreement with the experimental ones and could predict the increment produced in the collapse pressure by the effect of the thermal treatments. Comparison of the results with the predictions from API RP 1111 and DNV OS-F101 equations was also performed. The outcomes of this study will be employed to further optimize the collapse resistance of subsea linepipe in order to reduce material and offshore installation costs through the increment of the fabrication factor as stated in the DNV OSF101 standard.

Collapse and Buckling Behaviors of Reinforced Thermoplastic Pipe Under External Pressure

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Yong Bai ◽  
Nuosi Wang ◽  
Peng Cheng ◽  
Hongdong Qiao ◽  
Binbin Yu
Keyword(s):  
Theoretical Model ◽  
Three Dimensional ◽  
Element Model ◽  
External Pressure ◽  
Test Results ◽  
Equivalent Stiffness ◽  
3D Finite Element ◽  
Pressure Tests ◽  
Stiffness Method ◽  
Simulation Results

The collapse and buckling behaviors of reinforced thermoplastic pipe (RTP) under external pressure are studied in this paper. A theoretical model which includes axial and shear deformation is applied based on the model initially proposed by Kyriakides and his coworkers. Simulation of the reinforced layers of RTP is simplified using equivalent stiffness method. The load–displacement relation of RTP under external pressure is obtained based on the theoretical model. A three-dimensional (3D) finite element model (FEM) is also built to simulate the response of RTP using the software abaqus. Numerical simulation results from abaqus are similar to those from theoretical model. Besides, external pressure tests for RTP are carried out and the test results are compared with the analyzed results. Finally, factors that influence the external pressure capacity are also studied.

Sandwich Pipe: Reel-Lay Installation Effects

2015 ◽  
Author(s):  
Claudio Moura Paz ◽  
Guangming Fu ◽  
Segen Farid Estefen ◽  
Marcelo Igor Lourenço ◽  
John Alex H. Chujutalli
Keyword(s):  
Numerical Models ◽  
External Pressure ◽  
Experimental Models ◽  
Steel Pipes ◽  
Installation Effects ◽  
Collapse Resistance ◽  
Structural Resistance ◽  
Annular Layer ◽  
Collapse Behavior ◽  
Pva Fiber

Comprising an annular layer with adequate thermal insulation and structural resistance material enclosed by two concentric steel pipes, sandwich pipes could be an alternative for flowlines in ultra-deepwater for the pre-salt reservoirs in offshore Brazil. In this work, a numerical and experimental study was performed to investigate the collapse behavior of sandwich pipes considering the reel-lay installation method. Experimental models were manufactured using two different geometries of stainless steel pipes and strain hardening cementitious composites with PVA fiber (SHCC) in annular layer. One set of specimens was tested using a reel-lay apparatus and another set was kept intact. A hyperbaric chamber was then used to test both sets of specimens to collapse. The collapse resistance of the proposed sandwich structure was investigated, and the detrimental effect of the reeling strains to the collapse resistance was assessed. The numerical models simulated reeling and straightening loads during reel-lay installation and then the collapse under external pressure. The results were compared with experimental measurements and shown good agreement.

scholarly journals Finite Element Analysis of Cyclically-Loaded Steel Pipes During Deep Water Reeling Installation

2015 ◽  
Author(s):  
Giannoula Chatzopoulou ◽  
Spyros A. Karamanos ◽  
George E. Varelis
Keyword(s):  
Deep Water ◽  
Structural Response ◽  
Structural Instability ◽  
External Pressure ◽  
Combined Loading ◽  
Loading Path ◽  
Pipe Material ◽  
Element Analysis ◽  
Steel Pipes ◽  
Structural Capacity

Thick-walled steel pipes during their installation in deep-water are subjected to combined loading of external pressure and bending, which may trigger structural instability due to excessive pipe ovalization with catastrophic effects. The loading path followed during the reeling installation process is characterized by strong cyclic loading of the pipe material and results in residual stresses and deformations of the pipe cross-section, undermining the structural capacity of the pipe. Using advanced material tools, the present study examines the effect of reeling on the structural response and resistance of offshore pipes during the installation process.

Stress Analysis of Near Optimal Surface Notches in 3D Plates

2004 ◽  
Vol 127 (6) ◽  
pp. 1173-1183 ◽  
Author(s):  
R. Wescott ◽  
B. Semple ◽  
M. Heller
Keyword(s):  
Three Dimensional ◽  
Peak Stress ◽  
Finite Element Analyses ◽  
3D Finite Element ◽  
Aspect Ratios ◽  
Damage Repair ◽  
Elementary Methods ◽  
Notch Length ◽  
Optimal Surface ◽  
The Given

This paper presents a method of using two-dimensional (2D) optimal notch shapes to create near optimal surface notches with various depth and aspect ratios in uniaxially loaded three-dimensional (3D) plates. Axisymmetric and elongated surface notches are created by rotating 2D optimal notch shapes about two types of fixed axes, a major reason being to enable the surface notches to be manufactured by elementary methods. Stresses in the surface notches are determined using intensive 3D finite element analyses. Axisymmetric notches show small reductions in local peak stress relative to spherical notches with the same bounding dimensions. Local peak stresses in elongated notches are reduced by up to 26% relative to comparable spherical notches. The given method and results are transferable for the initial design, re-shaping, and damage repair of components manufactured from any commonly used metal. In damage removal applications a significant advantage of both notch types over spherical notches is that they allow more material to be extracted for the same notch length and maximum depth.

Pavement Damage Due to Conventional and New Generation of Wide-Base Super Single Tires

2005 ◽  
Vol 33 (4) ◽  
pp. 210-226 ◽  
Author(s):  
I. L. Al-Qadi ◽  
M. A. Elseifi ◽  
P. J. Yoo ◽  
I. Janajreh
Keyword(s):  
Carrying Capacity ◽  
Material Properties ◽  
Three Dimensional ◽  
Fe Analysis ◽  
Load Carrying Capacity ◽  
Inflation Pressure ◽  
3D Finite Element ◽  
Load Carrying ◽  
Pavement Damage ◽  
New Generation

Abstract The objective of this study was to quantify pavement damage due to a conventional (385/65R22.5) and a new generation of wide-base (445/50R22.5) tires using three-dimensional (3D) finite element (FE) analysis. The investigated new generation of wide-base tires has wider treads and greater load-carrying capacity than the conventional wide-base tire. In addition, the contact patch is less sensitive to loading and is especially designed to operate at 690kPa inflation pressure at 121km/hr speed for full load of 151kN tandem axle. The developed FE models simulated the tread sizes and applicable contact pressure for each tread and utilized laboratory-measured pavement material properties. In addition, the models were calibrated and properly validated using field-measured stresses and strains. Comparison was established between the two wide-base tire types and the dual-tire assembly. Results indicated that the 445/50R22.5 wide-base tire would cause more fatigue damage, approximately the same rutting damage and less surface-initiated top-down cracking than the conventional dual-tire assembly. On the other hand, the conventional 385/65R22.5 wide-base tire, which was introduced more than two decades ago, caused the most damage.

Buckling of Circular Cylindrical Shells Using a Displacement Function

1974 ◽  
Vol 96 (4) ◽  
pp. 1322-1327
Author(s):  
Shun Cheng ◽  
C. K. Chang
Keyword(s):  
Boundary Conditions ◽  
Axial Compression ◽  
Cylindrical Shells ◽  
External Pressure ◽  
Displacement Function ◽  
Combined Loading ◽  
Trial Solution ◽  
Governing Differential Equation ◽  
Circular Cylindrical Shells ◽  
The Stability

The buckling problem of circular cylindrical shells under axial compression, external pressure, and torsion is investigated using a displacement function φ. A governing differential equation for the stability of thin cylindrical shells under combined loading of axial compression, external pressure, and torsion is derived. A method for the solutions of this equation is also presented. The advantage in using the present equation over the customary three differential equations for displacements is that only one trial solution is needed in solving the buckling problems as shown in the paper. Four possible combinations of boundary conditions for a simply supported edge are treated. The case of a cylinder under axial compression is carried out in detail. For two types of simple supported boundary conditions, SS1 and SS2, the minimum critical axial buckling stress is found to be 43.5 percent of the well-known classical value Eh/R3(1−ν2) against the 50 percent of the classical value presently known.

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