Components

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Components

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The project sidebar for this example is shown in the figure below. The project sidebar shows all of the components that are used in the example. Each of these components is described in detail in the following sections.

 

Project Sidebar for Example 7

Project Sidebar for Example 7

 

Project Component

When a new PipeLay project is created it contains just a Project component. This component is used to store general project information such as the project title, location, and so on. The Project component is also used to specify certain project-specific settings such as the system of units to be used, global constants, finite element mesh settings and quality control procedures. For this example, the following information is stored in the general Project Settings dialog.

Table: General Project Settings

Property

Value

Project Title

Example 7 - Start-up via Sheave

Job Number

1-2-3-342

Engineer(s)

Wood Group

Location

Galway

For this example, the default Metric unit system and the default Constants dialog values are used. Also, the ‘Quality Control’ section is left as per default.

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Material Component

The Material component is used to define the physical properties associated with a particular material. This example contains two Material components, which define the material properties for both nonlinear X65 steel for the pipe section, as listed in the first table below, and linear steel for the cable, as listed in the second table below. The Material components are located in the Material folder and are named ‘X65 Steel’ and ‘Cable Steel’ respectively in this example.

 

Table: Material Properties for ‘X65 Steel’

Property

Value

Young's Modulus

207 GPa

Shear Modulus

80 GPa

Poisson’s Ratio

0.3

Mass Density

7850.0 kg/m3

Yield Strength

450 MPa

Allowable Stress

100 %

Allowable Strain

0.25 %

Expected Tension

0 kN

Nonlinear Axial Stiffness

Yes

Use Criteria Tension

Yes

 

 

Stress-Strain Curve for ‘X65 Steel’

Stress-Strain Curve for ‘X65 Steel’

 

 

Table: Material Properties for ‘Cable Steel’

Property

Value

Young's Modulus

207 GPa

Shear Modulus

79.9 GPa

Poisson’s Ratio

0.33

Mass Density

7798.3 kg/m3

Coefficient of Expansion

0 1/c

Yield Strength

448 MPa

Allowable Stress

100 %

Allowable Strain

0.25 %

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Pipe Section Component

The Pipe Section component is used to specify the properties of an individual section of pipeline that has uniform properties. This example contains one Pipe Section component as follows:

The Pipe Section component is created in the Line folder and is named ‘24" Pipe’.

The specification is Standard.

The material used is ‘X65 Steel’, as defined previously.

The geometrical and hydrodynamic properties are listed in the table below.

Table: Properties for ‘24’’ Pipe’

Property

Value

Outer Diameter

609.6 mm

Thickness

30 mm

Normal Drag

1

Normal Inertia

2

 

Cable Component

The Cable component is used to specify the properties of an individual section of cable that has uniform properties. It is similar to the Pipe Section component in many respects, though less complex, as no additional coatings or attachments may be specified. The same Cable component is used to model both winch cables as follows:

The Cable component is created in the Line folder and is named ‘Cable’.

The Standard specification is selected and the material used is ‘Cable Steel’, as defined previously.

A relatively low bending stiffness of 0.01 kNm² is explicitly defined.

The geometrical and hydrodynamic properties are listed in the table below.

Table: Properties for ‘Cable’

Property

Value

Diameter

100 mm

Normal Drag

1

Normal Inertia

2

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Ancillary Component

The Ancillary component is a general purpose component, which may be used to model a variety of appurtenances, such as pullheads, flanges, collars and so on. In this example, the ‘Cable’ is connected to the pipeline by means of an Ancillary component. The Ancillary component is created in the Line folder and is named ‘Pullhead’. The component is created with the properties of Weight in Air of 20 kN and Weight in Water of 17 kN.

 

Line Component

At this stage, enough components have been defined to allow for the specification of the pipeline stack-up, which is defined in a Line component named ‘Pipeline’.  A summary of the pipeline stack-up is provided in the table below.

Table: Pipeline Stack-Up

Section

Length

24’’ Pipe(1)

100 m

Pullhead(1)

-

Cable(1)

550 m

 

Support Components

This example contains two Support components to model the supports on both the vessel and the stinger. Both Support components are created in the Stinger folder. One component is a Double V Support, named ‘V-Rollerbox’, and the other component is a Zero Gap O Support, named ‘Tensioner Support. The ‘Tensioner Support’ component has a support length of 4.9 m. The properties of the ‘V-Rollerbox’ component are listed in the table below.

Table: Properties of ‘V-Rollerbox’

Property

Value

Support Length

2.45 m

Roller Length, L1

0 m

Roller Length, L2

1 m

Roller Length, L3

1 m

Roller Angle, Theta 1

30 deg

Roller Angle, Theta 2

90 deg

Contact Stiffness

5000 kN/m

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Tensioner Component

A single Tensioner component is used in the example, named ‘Tensioner Support’. As its name suggests, it is used as the Tensioner Support.

 

Stinger Component

A Stinger component named ‘Stinger’ is created to model the S-Lay stinger. Explicitly Defined is selected as the stinger definition option. The Support Locations of the stinger are listed in table below.

Table: Support Locations on ‘Stinger’

Support Name

X Coordinate (m)

Y Coordinate (m)

V-Rollerbox

-0.22

-4.49

V-Rollerbox

-2.2

-14.9

V-Rollerbox

-4.63

-25.22

V-Rollerbox

-7.51

-35.42

V-Rollerbox

-10.84

-45.48

V-Rollerbox

-14.61

-55.39

V-Rollerbox

-18.82

-65.12

V-Rollerbox

-23.45

-74.65

V-Rollerbox

-28.5

-83.98

 

 

 

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Vessel Component

A Vessel component named ‘Vessel for Normal Lay’ is created in the Vessel folder. This component models the lay vessel. The Standard Vessel Profile option is selected from the Profile Options drop-down list. The overall dimensions of the vessel are listed in the table below.

Table: Properties of ‘Vessel for Normal Lay’

Property

Value

Length

151.2 m

Depth of Keel below Origin

6.5 m

Horizontal Offset from Origin

75.6 m

Create Solid Profile

No

The Vessel Reference Point, Stinger Location and Support Locations are all also defined in the Vessel component, the properties of which are listed in the  tables below respectively.

Table: ‘Vessel for Normal Lay’ Reference Point

Property

Value

X Coordinate

2.811 m

Y Coordinate

74.145 m

Z Coordinate

-14 m

 

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Table: ‘Stinger’ Location

Property

Value

X Coordinate

0 m

Y Coordinate

0 m

Z Coordinate

0 m

Stinger Angle

0 degrees

 

Table: Support Locations on ‘Vessel for Normal Lay’

Support Name

X Coordinate (m)

Y Coordinate (m)

Tensioner

3.41

30.87

V-Rollerbox

2.58

17.99

V-Rollerbox

1.3

6.01

Radii of Curvature are specified on the Vessel component. This involves specifying two Y-coordinates for tangent points and their corresponding radii of curvature, as listed in the table below, which the ‘Vessel for Normal Lay’ and ‘Stinger’ supports are aligned upon. Specifying radii of curvature should ideally be carried out over a number of design iteration steps in order to achieve the optimum configuration (see Example 15 – Shallow Water Rigid S-Lay for an example of this design process).

Table: Radii of Curvature on ‘Vessel for Normal Lay’

Radius of Curvature (m)

Y Coordinate (m)

Analysis Optimisation

250

-5

No

999

-70

No

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Seabed Component

A single Seabed component is created in the Model folder and is named ‘Rigid Seabed’. In this example, a slope of -8 degrees is applied to the seabed. The remaining properties of a rigid seabed are left as default with a zero coefficient of friction in the longitudinal and transverse directions.

 

Sheave Component

This example contains a single Sheave component, named ‘Sheave’, with a Sheave Efficiency of 90%.

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