VIV Analysis of Deep Water Steel Catenary Riser Within Pull Tube

2013 ◽  
Author(s):  
Lun Qiu ◽  
Li Lee
Keyword(s):  
Cross Flow ◽  
Software Tool ◽  
Steel Tube ◽  
Careful Consideration ◽  
Single Chain ◽  
Tube System ◽  
Finite Element Program ◽  
Steel Catenary Riser ◽  
Entire Structure ◽  
Element Program

The method of pulling a steel catenary riser (SCR) through a steel tube (termed as a pull tube) is common practice for deepwater riser tie back applications. Vortex-induced vibration (VIV) of such a system is complex. VIV analysis programs, such as Shear7 [1], are suitable only for a single, chain-like structure. The application of such a software tool in VIV design of the SCR-pull tube system requires careful consideration of a number of structural and hydrodynamic factors. This paper presents a methodology for VIV analysis of the combined structural system of the SCR with the pull tube. Firstly, the entire SCR-pull tube system is modeled with the finite element program Flexcom [2]. The modes are then calculated for the entire structure with program Modes [3]. Afterwards, the structural nodes are rearranged for VIV analysis with Shear7. The pull tube is secured on the platform through a number of guides on the truss structure of the hull. The diameter of the pull tube is much larger than that of the SCR, and the pull tube is much stiffer in bending than the SCR is. If the entire structure is analyzed with Shear7, the mode for the pull tube (a mode involving a large motion of the pull tube section), which is very high in order, would be embedded in the analysis. It makes sense to single out the pull tube mode for study as if it is the first mode. A computer program, named as V-Span [4] for subsea span VIV analysis, is used to analyze both in-line and cross-flow VIV of the pull tube. A numerical example is presented to demonstrate this methodology. This is a deepwater SCR, which has a diameter of 9 inches. The water depth is 6,300 ft. The pull tube is 640 feet long and 20 inch in diameter. Both the loop-eddy and background currents are analyzed. The fatigue damage resulted from both in-line and cross-flow VIV is estimated.

Finite Element Analysis on the Bearing Capacity of Tube-Plate Joint with Different Width-Thickness Ratio

2012 ◽  
Vol 204-208 ◽  
pp. 1224-1228
Author(s):  
Jun Fen Yang ◽  
Yi Liang Peng ◽  
Xia Bing Wei ◽  
Jin Bo Cui
Keyword(s):  
Experimental Investigation ◽  
Finite Element ◽  
Bearing Capacity ◽  
Steel Tube ◽  
Thickness Ratio ◽  
Deformation Condition ◽  
Tube Plate ◽  
Element Analysis ◽  
Finite Element Program ◽  
Element Program

Tube-plate joint is a frequently-used joint type in steel-tube tower, but the theoretical analysis and experimental investigation on tube-plate joint are absent both at home and abroad. In this paper, the ANSYS finite element program was used to simulate the bearing capacity and deformation condition of tube-plate joint with 1/2-stiffening ring. Eight calculation models were designed, and the width-thickness ratio was changed by changing the width or thickness of stiffening ring. The results indicate that the influence of different width-thickness ratio on tube-plate joint bearing capability is significant. By increasing the width or increasing the thickness of stiffening rings to improve the bearing capacity of the joint is a very effective way.

On Remaining Fatigue Life Fracture Mechanics Analysis of Free-Spanning Pipelines Using Shell and Line-Spring Elements

2002 ◽  
Author(s):  
F. Redaelli ◽  
B. Skallerud ◽  
B. J. Leira
Keyword(s):  
Fatigue Life ◽  
Fracture Mechanics ◽  
Crack Growth ◽  
Cross Flow ◽  
Finite Element Program ◽  
Shell Elements ◽  
Cyclic Stresses ◽  
Vortex Induced Vibrations ◽  
Element Program ◽  
Remaining Fatigue Life

The present paper addresses fatigue crack-growth for free-spanning pipelines. The main sources of cyclic stresses which cause the crack-growth are vortex-induced vibrations (VIV) of the pipeline in the cross-flow and in-line directions. In the presence of initial weld defects, such cyclic stresses may lead to leakage and sudden fracture. The crack-growth process is modelled using so-called line-spring elements. These are matched with shell elements which are applied for modelling the pipe itself. The crack-growth is simulated by performing several simulations with different crack sizes. The shape of the crack also allowed to vary during the growth (i.e a/c-ratio). The static equilibrium position of the pipeline for a specific free span is first established by the non-linear Finite Element program ABAQUS. The line-spring elements are matched to interface with the shell elements which represent the pipe outside the region where the crack is located. Based on such simulations, the stress intensity factors at the crack-tip are computed. These calculations are performed for several different crack-sizes. Finally, the remaining fatigue life is estimated by means of fracture mechanics in terms of analytical and semi-empirical approaches.

Structural behavior of recycled aggregates concrete filled steel tubular columns

2017 ◽  
Vol 8 (1) ◽  
pp. 17 ◽  
Author(s):  
Boshra Eltaly ◽  
Ahmed Bembawy ◽  
Nageh Meleka ◽  
Kameel Kandil
Keyword(s):  
Finite Element ◽  
Steel Tube ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Experimental Program ◽  
Element Analysis ◽  
Finite Element Program ◽  
Tubular Columns ◽  
Coarse Aggregates ◽  
Element Program

This paper presents an experimental and numerical investigation to determine the behavior of steel tubular columns filled with recycled aggregates concrete up to failure under constant axial compression loads. The experimental program included two steel tube columns, four recycled concrete columns and eight composite columns filled with different types of recycled coarse aggregates (granite and ceramic). Different percentages of recycled coarse aggregates: 0, 25 and 50 of the percentage of the coarse aggregates (dolomite) were used. The results of the numerical model that was employed by the finite element program, ANSYS, were compared with the experimental results. The results of the experimental study and the finite element analysis were compared with the design equations using different national building codes: AISC1999, AISC2005 and EC4. The results indicated that the recycled aggregates concrete infill columns have slightly lower but comparable ultimate capacities compared with the specimens filled with normal concrete.

Analysis of Large-Span Steel Concrete Railway Arch Bridge Suspender Tension

2013 ◽  
Vol 361-363 ◽  
pp. 1259-1263 ◽  
Author(s):  
Jia Lin Xu
Keyword(s):  
Bending Moment ◽  
Internal Force ◽  
Steel Tube ◽  
Force Balance ◽  
Initial Tension ◽  
Finite Element Program ◽  
Arch Bridge ◽  
Reverse Sequence ◽  
Element Program ◽  
Force Calculation

In this paper the concrete-filled steel tube concrete arch bridge as the research object, through the finite element program MIDAS, analyzes the internal force of the whole bridge, determined the distribution of internal force and the most unfavorable position; Using the force balance method, taking the reasonable stress of the bending moment status to control goals, determines the boom of the bridge as the condition of reasonable internal force; Use fall down method, according to the reverse sequence in order to cut the boom, each cut as a model for internal force calculation and analysis, get the next will be cut derrick's internal force, its value is the order construction boom of the initial tension.

Numerical Analysis of RPC-Filled Circular Steel Tube Columns

2011 ◽  
Vol 291-294 ◽  
pp. 396-400 ◽  
Author(s):  
Yan Wang ◽  
Guan Yuan Zhao
Keyword(s):  
High Performance ◽  
Steel Tube ◽  
Axial Loads ◽  
Finite Element Program ◽  
Circular Steel Tube ◽  
Element Program ◽  
Loading Modes ◽  
Reactive Powder ◽  
Relationship Of ◽  
Force Displacement

Reactive Powder Concrete(RPC) is a cementitious material that exhibits high performance properties. Brittle failure mode usually appears when it is subjected to high or complicated stress. The fragility performance of RPC can be great improved if efficient confinement is provided. In this paper, four RPC-filled steel tube stub columns under axial loads were analyzed using the finite element program ABAQUS. Two different axially loading modes were considered. The analysis results were compared with the results of the tests. It was found that the FEM models can predict the force-displacement relationship of such columns with acceptable accuracy.

scholarly journals Assessment of the non-linear behaviour of plastic ankle foot orthoses by the finite element method

2000 ◽  
Vol 214 (5) ◽  
pp. 527-539 ◽  
Author(s):  
S Syngellakis ◽  
M A Arnold ◽  
H Rassoulian
Keyword(s):  
Finite Element ◽  
Experimental Studies ◽  
Careful Consideration ◽  
Foot Orthoses ◽  
Finite Element Program ◽  
Ankle Foot Orthoses ◽  
Non Linear ◽  
Linear Behaviour ◽  
Element Program ◽  
Alternative Means

The stiffness characteristics of plastic ankle foot orthoses (AFOs) are studied through finite element modelling and stress analysis. Particular attention is given to the modelling and prediction of non-linear AFO behaviour, which has been frequently observed in previous experimental studies but not fully addressed analytically. Both large deformation effects and material non-linearity are included in the formulation and their individual influence on results assessed. The finite element program is subsequently applied to the simulation of a series of tests designed to investigate the relation between AFO trimline location and stiffness for moderate and large rotations. Through careful consideration and identification of key modelling parameters, the developed finite element solution proves to be a reliable and effective alternative means of assessing variations of a typical plastic AFO design so that particular patient requirements could be met, in the long term.

Finite Element Analysis of Axially Loaded RPC Filled Long Circular Steel Tube Columns

2013 ◽  
Vol 779-780 ◽  
pp. 352-355
Author(s):  
Zhi Gang Yan ◽  
Jun Yang ◽  
Hua Luo
Keyword(s):  
Finite Element ◽  
Slenderness Ratio ◽  
High Strength ◽  
Steel Tube ◽  
Element Analysis ◽  
Finite Element Program ◽  
Circular Steel Tube ◽  
Element Program ◽  
Reactive Powder ◽  
Structural Engineers

In recent years, Reactive Powder Concrete (RPC) has been concerned by the structural engineers and researchers. RPC is a kind of cement-based composite which has ultra-high strength, high ductility and durability, however, it has great fragility. The fragility performance of RPC will be improved if RPC and steel are put together as RPC-filled steel tube circular stub columns. The aim of this paper is to develop accurate finite element models to simulate the behavior of RPC-filled steel tube circular long columns. The finite element program ABAQUS is used in the analysis. An extensive parametric study is conducted to investigate the effects of different slenderness ratio and confinement action on the strength and behavior of RPC-filled steel tube circular long columns. The results obtained from the models are verified against the results of the tests. The results show that the rising part of load-strain curves are in good agreements with experiment results.

Temperature Field Calculation and Analysis within Steel Tube Reinforced Columns

2011 ◽  
Vol 243-249 ◽  
pp. 5089-5093 ◽  
Author(s):  
Lei Xu ◽  
Yu Bin Liu
Keyword(s):  
Temperature Field ◽  
Theoretical Models ◽  
Steel Tube ◽  
Area Ratio ◽  
Core Area ◽  
Field Calculation ◽  
Steel Tubes ◽  
Finite Element Program ◽  
Element Program ◽  
Rising Time

Theoretical models to calculate the temperature field steel tubes reinforced columns are proposed by finite element program in this paper. The theoretical results are validated by test results, and they have a good agreement. Using the theoretical models, the influencing laws of temperature rising time; section perimeter; steel reinforcement ratio and sectional core area ratio on temperature field are further discussed. It has been found that the surface temperatures of steel tube reinforced columns increase obviously with temperature rising time, and the temperatures of steel tubes and core concrete increase slowly. The effects of sectional dimension and sectional core area ratio on temperature field are significant, but steel ratio has very little effect on temperature both of steel tube and of sectional center. These achievements make it possible to study further theoretical study on the mechanic performance of steel tube reinforced concrete columns in fire.

The Analysis of Double-Nonlinearity Stability of Concrete Filled Steel-Tube Arch Bridge

2013 ◽  
Vol 724-725 ◽  
pp. 1709-1713 ◽  
Author(s):  
Xing Han ◽  
Bing Zhu ◽  
Gui Man Liu ◽  
Jun Ping Wang ◽  
Bao Shan Xiang
Keyword(s):  
Finite Element ◽  
Nonlinear Analysis ◽  
Steel Tube ◽  
Eigenvalue Analysis ◽  
Finite Element Program ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Element Program ◽  
Load Displacement ◽  
The Stability

Taking a concrete-filled steel tube arch bridge with a span of 80m for example, the paper studies the stability of this bridge by using the general finite element program. The analysis introduces the method to deal with the stability of these bridges by FEM, also demonstrates the result of the eigenvalue analysis and dual nonlinear analysis according to an example. In eigenvalue analysis, the influence of the brace and the X-brace to this arch bridge`s stability are compared under different load cases; in dual nonlinear analysis, the load-displacement curves of three different load cases of the rib failure are given. All of these are some valuable to the stability of the concrete-filled steel tube arch bridge.

Coupled Analysis of SCR and Flowline Under High Pressure and High Temperature

2014 ◽  
Author(s):  
C. H. Luk ◽  
Xinhai Qi ◽  
Jianxia Zhong
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Thermal Stresses ◽  
Dynamic Responses ◽  
Coupled Analysis ◽  
Finite Element Program ◽  
Steel Catenary Riser ◽  
Element Program ◽  
Lateral Displacements ◽  
Vessel Motion

This paper presents a coupled design analysis for a Pipe-in-Pipe (PIP) Steel Catenary Riser (SCR) and Flowline (FL) system in 5000ft of water under high pressure and high temperature (HP/HT) conditions in the Gulf of Mexico (GOM). The finite element program ABAQUS is used to model the inner and outer pipes of the PIP system, the centralizer, the SCR hangoff, the flowline lateral and end supports, and pipe-soil interactions on the seabed. Thermal stresses and stress ranges caused by repeated temperature transients, axial and lateral displacements of SCR and flowline, as well as by the dynamic responses of the coupled riser and flowline system, are presented. Comparisons are also made with results by ABAQUS models with beam and pipe elements, and results obtained by coupled and de-coupled analysis. The sample vessel motion was obtained for an example Spar platform in GOM.

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