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 12

Project Sidebar for Example 12

 

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 12 - DMA Start-up

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

No

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 ‘16" 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 ‘16’’ Pipe’

Property

Value

Outer Diameter

406.4 mm

Thickness

20 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. There is only one cable used in this project as follows:

The Cable component is created in the Line folder and is named ‘DMA 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 ‘DMA 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 ‘DMA Cable’ is connected to the pipeline by means of an Ancillary component. The Ancillary component, named ‘Start-up Head’, is created using the Complex option for the Ancillary Type. The table below contains the physical properties for the component.

Table: Properties for ‘Start-up Head’

Property

Value

Weight in Air

100 kN

Weight in Water

20 kN

Length

10 m

Overall OD

600 mm

Inner Diameter

500 mm

Bending Stiffness

1.0E+10 kNm²

Axial Stiffness

1.0E+10 kN

Normal Drag

1

Normal Inertia

2

 

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

16’’ Pipe(1)

50 m

Start-up Head(1)

10 m

DMA Cable(1)

705 m

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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 2 m. The properties of the ‘V-Rollerbox’ component are listed in the table below.

Table: Properties of ‘V-Rollerbox’

Property

Value

Support Length

1 m

Roller Length, L1

0 m

Roller Length, L2

1.5 m

Roller Length, L3

0 m

Roller Angle, Theta 1

30 deg

Roller Angle, Theta 2

90 deg

Contact Stiffness

5000 kN/m

Axial Rotation

0 deg

 

Tensioner Component

A single Tensioner component is created in the ‘Stinger’ folder, named ‘Tensioner’. ‘Zero-Gap Guide’ is used as the Tensioner Support.

 

Stinger Component

A Stinger component is created to model the S-Lay stinger, named ‘Stinger’ in this example. Radius of Curvature Defined is selected as the stinger definition option. The Support Locations on the stinger are given in the table below.

Table: Support Locations on ‘Stinger’

Support Name

Support Location (m)

V-Rollerbox

0

V-Rollerbox

12.2

V-Rollerbox

24.4

V-Rollerbox

36.6

V-Rollerbox

61

V-Rollerbox

73.2

V-Rollerbox

85.4

V-Rollerbox

97.6

V-Rollerbox

109.8

V-Rollerbox

122

 

The Support Locations corresponds to the curvilinear distance along the arc from the top of the stinger, which is defined as being directly below the Centre of Curvature. The Centre of Curvature for the stinger is defined in the table below.

Table: Centre of Curvature for ‘Stinger’

Property

Value

Centre of Curvature – X

-120 m

Centre of Curvature – Y

0 m

Radius of Curvature

120 m

 

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Vessel Component

A Vessel component named ‘Lay Vessel’ 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 ‘Lay Vessel’

Property

Value

Length

220 m

Depth of Keel below Origin

15 m

Horizontal Offset from Origin

0 m

Create Solid Profile

No

 

The Stinger Location and Support Locations are also defined on the Vessel component, the properties of which are given in two tables below respectively.

Table: ‘Stinger’ Location

Property

Value

X Coordinate

4.8 m

Y Coordinate

-93.1 m

Z Coordinate

0 m

Stinger Angle

180°

Table: Support Locations on ‘Lay Vessel’

Support Name

X Coordinate (m)

Y Coordinate (m)

Z Coordinate (m)

Tensioner

4.8314

28.8

0

V-Rollerbox

4.8

16.6

0

V-Rollerbox

4.8

4.4

0

V-Rollerbox

4.8

-7.8

0

V-Rollerbox

4.8

-20

0

V-Rollerbox

4.8

-32.2

0

V-Rollerbox

4.8

-44.4

0

V-Rollerbox

4.8

-56.6

0

V-Rollerbox

4.8

-68.8

0

V-Rollerbox

4.8

-81.0

0

 

Vessel Offset Component

The Vessel Offset component is used to specify the static offset that is to be applied to a vessel in an analysis. In this example there is only one Vessel Offset component, named ‘50m Offset’, which defines a surge offset of 50 m.

 

Seabed Component

A single Seabed component is created in the Model folder, named ‘Elastic Seabed’. The seabed stiffness is specified as 1000 kN/m/m while the remaining default properties are left unchanged.

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