Loading History Effects for Deep-Water S-Lay of Pipelines

2004 ◽  
Vol 126 (2) ◽  
pp. 156-163 ◽  
Author(s):  
Heedo D. Yun ◽  
Ralf R. Peek ◽  
Paul R. Paslay ◽  
Frans F. Kopp
Keyword(s):  
Deep Water ◽  
Numerical Solutions ◽  
Pipe Material ◽  
Loading History ◽  
Material Models ◽  
Plastic Deformations ◽  
History Effects ◽  
Departure Angle ◽  
Numerical Finite Element ◽  
The Moment

For economic reasons S-Lay is often preferred to J-Lay. However in very deep water S-Lay requires a high curvature of the stinger to achieve the required close-to-vertical departure angle (or a large, low curvature stinger). Choosing the high curvature stinger can lead to plastic deformations of the pipe. The high top tension increases the plastic deformations in two ways: firstly it adds an overall tensile component to the strains, thereby increasing the strains at the 12 o’clock position. Secondly, it increases the strain concentrations, which arise due to discontinuous support of the pipe on the stinger. Typically, the pipe is guided over a series of roller beds. The high top tension tends to straighten the spans between the rollerbeds. To accommodate this (so that the pipe can still follow the stinger), higher curvatures occur at the roller beds. Analytical and numerical solutions are provided to quantify this effect. The analytical solution is fully developed for an arbitrary pipe material models, provided that: (i) the moment-curvature relation for the pipe under tension is known, and (ii) no cyclic plastic ratchetting occurs due to repeated bending of the pipe over the roller beds and straightening in the spans between roller beds. Agreement between the analytical and numerical (finite element) results is excellent. Proper loading history must be used in the numerical simulation, otherwise the level of strain concentration can be overpredicted.

Loading History Effects for Deepwater S-Lay of Pipelines

2003 ◽  
Author(s):  
Heedo D. Yun ◽  
Ralf R. Peek ◽  
Paul P. Paslay ◽  
Frans F. Kopp
Keyword(s):  
Numerical Solutions ◽  
Loading History ◽  
Material Models ◽  
Plastic Deformations ◽  
Perfectly Plastic ◽  
History Effects ◽  
Departure Angle ◽  
Numerical Finite Element ◽  
Elastic Perfectly Plastic ◽  
The Moment

For economic reasons S-Lay is often preferred to J-Lay. However in very deep water S-Lay requires a high curvature of the stinger to achieve the required close-to-vertical departure angle. This can lead to plastic deformations of the pipe. The high top tension increases the plastic deformations in two ways: firstly it adds an overall tensile component to the strains, thereby increasing the strains at the 12 o’clock position. Secondly it increases the strain concentrations which arise due to discontinuous support of the pipe on the stinger. Typically the pipe is guided over a series of roller beds. The high top tension tends to straighten the spans between the roller beds. To accommodate this (so that the pipe can still follow the stinger), higher curvatures are required at the roller beds. Analytical and numerical solutions are provided to quantify this effect. The analytical solution is fully developed for an elastic-perfectly-plastic pipe, but can also be applied for other material models provided that: (i) the moment-curvature relation for the pipe under tension is known, and (ii) no cyclic plastic ratchetting occurs due to repeated bending of the pipe over the roller beds and straightening in the spans between roller beds. Agreement between the analytical and numerical (finite element) results is excellent, if the proper loading history is used in the numerical simulation. Otherwise the level of strain concentration can be overpredicted.

Development of X90 and X100 Steel Grades for Seamless Linepipe Products

2014 ◽  
Author(s):  
Diana Toma ◽  
Silke Harksen ◽  
Dorothee Niklasch ◽  
Denise Mahn ◽  
Ashraf Koka
Keyword(s):  
Wall Thickness ◽  
Deep Water ◽  
High Strength ◽  
Oil And Gas Industry ◽  
Pipe Material ◽  
Line Pipe ◽  
Materials Development ◽  
Additional Tool ◽  
Technical Requirements ◽  
Steel Grades

The general trend in oil and gas industry gives a clear direction towards the need for high strength grades up to X100. The exploration in extreme regions and under severe conditions, e.g. in ultra deep water regions also considering High Temperature/High Pressure Fields or arctic areas, becomes more and more important with respect to the still growing demand of the world for natural resources. Further, the application of high strength materials enables the possibility of structure weight reduction which benefits to materials and cost reduction and increase of efficiency in the pipe line installation process. To address these topics, the development of such high strength steel grades with optimum combination of high tensile properties, excellent toughness properties and sour service resistivity for seamless quenched and tempered pipes are in the focus of the materials development and improvement of Vallourec. This paper will present the efforts put into the materials development for line pipe applications up to grade X100 for seamless pipes manufactured by Pilger Mill. The steel concept developed by Vallourec over the last years [1,2] was modified and adapted according to the technical requirements of the Pilger rolling process. Pipes with OD≥20″ and wall thickness up to 30 mm were rolled and subsequent quenched and tempered. The supportive application of thermodynamic and kinetic simulation techniques as additional tool for the material development was used. Results of mechanical characterization by tensile and toughness testing, as well as microstructure examination by light-optical microscopy will be shown. Advanced investigation techniques as scanning electron microcopy and electron backscatter diffraction are applied to characterize the pipe material up to the crystallographic level. The presented results will demonstrate not only the effect of a well-balanced alloying concept appointing micro-alloying, but also the high sophisticated and precise thermal treatment of these pipe products. The presented alloying concept enables the production grade X90 to X100 with wall thickness up to 30 mm and is further extending the product portfolio of Vallourec for riser systems for deepwater and ultra-deep water application [1, 3, 4].

scholarly journals Time influence of tunnel support on the factor of safety

2020 ◽  
Vol 157 ◽  
pp. 06002
Author(s):  
Ivana Nedevska ◽  
Zlatko Zafirovski ◽  
Slobodan Ognjenovic ◽  
Ivona Nedevska ◽  
Vasko Gacevski
Keyword(s):  
Rock Mass ◽  
Stress State ◽  
Factor Of Safety ◽  
Tunnel Excavation ◽  
Tunnel Support ◽  
Plastic Deformations ◽  
Primary Stress ◽  
Reaction Curve ◽  
State Changes ◽  
The Moment

Before taking any measures to build a tunnel, the rock (soil) is in a primary stress state, which means that the stress state is a function of the thickness of the overburden. At the moment when the measures necessary to excavate a tunnel are taken, the rock state changes from primary to secondary, leading to stress concentration, especially in the tunnel abutments. If the rock is capable of accepting these stresses, a state of equilibrium is reached after certain deformations. Plastic deformations can occur if the stresses are larger than the strength of the rock mass. To avoid excessive deformations or collapse of the rock and the tunnel excavation, it is necessary to place a support. The achieved factor of safety is a function of both the support type and the time when the support is installed. This paper shall present a numerical example of different pressures considered in order to obtain the rock’s reaction curve.

scholarly journals Numerical modeling of a clean shift for perfectly elastic-plastic material (Murnaghan’s material)

2019 ◽  
Vol 64 (2) ◽  
pp. 182-189
Author(s):  
O. L. Shved
Keyword(s):  
Fracture Criterion ◽  
Plastic Material ◽  
Pure Shear ◽  
Growth Parameter ◽  
Specific Power ◽  
Loading History ◽  
Elastic Plastic ◽  
Fortran Language ◽  
Elastic Plastic Material ◽  
The Moment

The constitutive equations are formulated for the case when the process point is located at the singular point of the deviator section of the yield surface. The main parameter of Murnaghan’s elastic-plastic material is selected – the relative part of the dissipated specific power of deformation. This value depends on the type of stress-strain state, strain rate and material loading history. This dependence is due to the rational choice of the growth parameter of the elastic deformation anisotropy, which ensures its minimum value. Complex programs in FORTRAN language have been developed and the pure shift process has been numerically simulated. The results of calculations of the process carried out before the moment of material destruction according to the proposed non-standard fracture criterion are presented. The phenomenon of increasing the plasticity of the material for pure shear with applied high hydrostatic pressure is described. Bridgman’s experimental data on the presence of a threshold pressure value for hard-to-deform metals is confirmed.

Quelques aspects des conditions de depot du flysch

1962 ◽  
Vol S7-IV (1) ◽  
pp. 41-48 ◽  
Author(s):  
Marguerite Rech-Frollo
Keyword(s):  
Shallow Water ◽  
Deep Water ◽  
Organic Material ◽  
Detrital Material ◽  
Water Origin ◽  
The Moment ◽  
Bird Tracks ◽  
Marine Basin

Abstract Analysis of the Niesen flysch between Le Sepey and Mosses lake does not confirm the deep-water bathymetry commonly attributed to flysch deposits. The juxtaposition of organic material over continental alluvium--a typical flysch characteristic--was observed only at shallow depths. The muddy sands, source of the flysch deposits, are actually formed at shallow depths. Bird tracks reported from certain flysch beds also suggest shallow-water origin for the deposits. Cross currents produced after periodic disruption of tectonic and climatic equilibria in parts of a marine basin corresponding to the continental platforms explain the mechanical sorting of the organisms and detrital material as well as the granoclastic structure of the flysch. After deposition of the flysch and before its compaction orogenic mobility at the bottom of the basin affected the petrography of the flysch causing corrosion of the quartz and feldspars at the moment of consolidation. Evidence presented by proponents of a deep-water origin for the flysch deposits--based on foraminifera and the petrographic and paleo-oceanographic characters of the deep-water sands--is reviewed.

KAJIAN PENGARUH PENGGUNAAN SEMEN EKSPOS SEBAGAI FINISHING DINDING INTERIOR TERHADAP PSIKOLOGIS PENGGUNA RUANG

AKSEN ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 43-51
Author(s):  
I Gede Made Gani Rakandenu ◽  
Dyah Kusuma Wardhani
Keyword(s):  
Industrial Design ◽  
Residential Buildings ◽  
Commercial Buildings ◽  
Pipe Material ◽  
Color Palette ◽  
Great Demand ◽  
Interior Wall ◽  
The Moment ◽  
Design Style

The use of exposed cement materials as wall finishing lately is in great demand and is becoming a designtrend at the moment. Many property buildings ranging from commercial buildings such as cafes, restaurants,to hotels to residential buildings such as houses, apartments and condos use exposed cement as one ofthe interior wall finishing. Exposed cement as wall finishing is usually associated with industrial designstyles. In Indonesia, exposed cement is applied as finishing material after bricks. Using exposed cementas wall finish that nowadays has been trending in architecture and interior applicants gives a differentambience of space, home or building yet still economically acceptable. The using of exposed cement aswall finish are close to the using of industrial style. As known, industrial style is an interior architecturedesign style that adopting industries elements such as the using of metal, bricks and pipe material thenbe exposed on purpose. Industrial style has color palette such as black and greyish. Therefore the usingof exposed cement as wall finish often used in industrial design style. However with the popular use ofexposed cement as wall finish does not mean that it can freely acceptable in all situations, because it canaffect the comfort of the room user.

Finite Biaxial Extension of Completely Set Plain Woven Fabrics

1979 ◽  
Vol 46 (3) ◽  
pp. 651-655 ◽  
Author(s):  
N. C. Huang
Keyword(s):  
Residual Stress ◽  
Boundary Value Problem ◽  
Mechanical Behavior ◽  
Nonlinear Boundary ◽  
Numerical Solutions ◽  
Woven Fabrics ◽  
Trial And Error ◽  
Biaxial Extension ◽  
Curved Rods ◽  
The Moment

This paper is concerned with the analysis of the finite biaxial extension of completely set plain woven fabrics with the yarns treated as curved rods. The undeformed configuration of the yarn is assumed to consist of segments of elastica resulting from deformed cantilevers under transverse end loads. In the undeformed state, there is no residual stress in the yarn. During deformation of the fabric, yarns are subjected to extension and bending. The mechanical behavior of the yarn is regarded as linearly elastic in extension. However, for the flexural deformation, due to loss in friction between fibers, the moment-curvature relation is bilinear. A nonlinear boundary-value problem can be formulated for the finite biaxial extension phenomenon of the fabric. Numerical solutions are sought by a trial and error procedure.

Minimum Wall Thickness Requirements for Ultra Deep-Water Pipelines

2003 ◽  
Author(s):  
Enrico Torselletti ◽  
Luigino Vitali ◽  
Roberto Bruschi ◽  
Leif Collberg
Keyword(s):  
Wall Thickness ◽  
Deep Water ◽  
Failure Modes ◽  
Limit State ◽  
Strain Curve ◽  
External Pressure ◽  
Design Guidelines ◽  
Compressive Yield Strength ◽  
Pipe Material ◽  
Line Pipe

The offshore pipeline industry is planning new gas trunklines at water depth ever reached before (up to 3500 m). In such conditions, external hydrostatic pressure becomes the dominating loading condition for the pipeline design. In particular, pipe geometric imperfections as the cross section ovality, combined load effects as axial and bending loads superimposed to the external pressure, material properties as compressive yield strength in the circumferential direction and across the wall thickness etc., significantly interfere in the definition of the demanding, in such projects, minimum wall thickness requirements. This paper discusses the findings of a series of ultra deep-water studies carried out in the framework of Snamprogetti corporate R&D. In particular, the pipe sectional capacity, required to sustain design loads, is analysed in relation to: • The fabrication technology i.e. the effect of cold expansion/compression (UOE/UOC) of TMCP plates on the mechanical and geometrical pipe characteristics; • The line pipe material i.e. the effect of the shape of the actual stress-strain curve and the Y/T ratio on the sectional performance, under combined loads; • The load combination i.e. the effect of the axial force and bending moment on the limit capacity against collapse and ovalisation buckling failure modes, under the considerable external pressure. International design guidelines are analysed in this respect, and experimental findings are compared with the ones from the application of proposed limit state equations and from dedicated FE simulations.

scholarly journals Accurate solution method for the Maxey–Riley equation, and the effects of Basset history

2019 ◽  
Vol 868 ◽  
pp. 428-460 ◽  
Author(s):  
S. Ganga Prasath ◽  
Vishal Vasan ◽  
Rama Govindarajan
Keyword(s):  
Numerical Scheme ◽  
Numerical Solutions ◽  
Point Vortex ◽  
Accurate Solution ◽  
Time Dependent ◽  
Inertial Particles ◽  
Spectral Accuracy ◽  
Transform Method ◽  
History Effects ◽  
History Force

The Maxey–Riley equation has been extensively used by the fluid dynamics community to study the dynamics of small inertial particles in fluid flow. However, most often, the Basset history force in this equation is neglected. Analytical solutions have almost never been attempted because of the difficulty in handling an integro-differential equation of this type. Including the Basset force in numerical solutions of particulate flows involves storage requirements which rapidly increase in time. Thus the significance of the Basset history force in the dynamics has not been understood. In this paper, we show that the Maxey–Riley equation in its entirety can be exactly mapped as a forced, time-dependent Robin boundary condition of the one-dimensional diffusion equation, and solved using the unified transform method. We obtain the exact solution for a general homogeneous time-dependent flow field, and apply it to a range of physically relevant situations. In a particle coming to a halt in a quiescent environment, the Basset history force speeds up the decay as a stretched exponential at short time while slowing it down to a power-law relaxation, ${\sim}t^{-3/2}$, at long time. A particle settling under gravity is shown to relax even more slowly to its terminal velocity (${\sim}t^{-1/2}$), whereas this relaxation would be expected to take place exponentially fast if the history term were to be neglected. An important mechanism for the growth of raindrops is by the gravitational settling of larger drops through an environment of smaller droplets, and repeatedly colliding and coalescing with them. Using our solution we estimate that the rate of growth rate of a raindrop can be grossly overestimated when history effects are not accounted for. We solve exactly for particle motion in a plane Couette flow and show that the location (and final velocity) to which a particle relaxes is different from that due to Stokes drag alone. For a general flow, our approach makes possible a numerical scheme for arbitrary but smooth flows without increasing memory demands and with spectral accuracy. We use our numerical scheme to solve an example spatially varying flow of inertial particles in the vicinity of a point vortex. We show that the critical radius for caustics formation shrinks slightly due to history effects. Our scheme opens up a method for future studies to include the Basset history term in their calculations to spectral accuracy, without astronomical storage costs. Moreover, our results indicate that the Basset history can affect dynamics significantly.

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