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 1

Project Sidebar for Example 1

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 1 – Normal S-Lay

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 one Material component, which defines the non-linear material properties for X65 steel, as listed in the table below. The Material component is created in the Material folder and is named ‘X65 Steel’ 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’

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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

28 mm

Normal Drag

1

Normal Inertia

2

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Line Component

The Line component is created in the Line folder and is named ‘Pipeline’. This Line component contains 4500 m of the Pipe Section component ‘24’’ Pipe(1)’.

 

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 ‘Zero Gap Guide’. The ‘Zero Gap Guide’ component has a support length of 5 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 m

Roller Length, L3

1 m

Roller Angle, Theta 1

30 deg

Roller Angle, Theta 2

90 deg

Contact Stiffness

5000 kN/m

Axial Rotation

0 deg

Longitudinal Coefficient of Friction

0

Transverse Coefficient of Friction

0

 

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Tensioner Component

A single Tensioner component is created in the Stinger folder and is named ‘Tensioner’. The Type is specified as Linear, while the Coefficient Type is specified as Active with default Damper properties. ‘Zero-Gap Guide’ is used as the Tensioner Support Stinger Component.

 

Stinger Component

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

Table: Support Locations on ‘Stinger’

Support Name

X Coordinate (m)

Y Coordinate (m)

V-Rollerbox

4.7528

18.2

V-Rollerbox

4.7528

6.0

V-Rollerbox

4.7528

-5.6

V-Rollerbox

4.7528

-17.6

V-Rollerbox

4.7528

-29.6

V-Rollerbox

4.7528

-41.6

V-Rollerbox

4.7528

-53.6

V-Rollerbox

4.7528

-65.6

V-Rollerbox

4.7528

-77.6

V-Rollerbox

4.7528

-90.6

V-Rollerbox

4.7528

-105.6

V-Rollerbox

4.7528

-125.6

V-Rollerbox

4.7528

-150.6

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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

110 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 three tables below respectively.

Table: Reference Point of ‘Lay Vessel’

Property

Value

X Coordinate

0 m

Y Coordinate

125 m

Z Coordinate

0.0 m

 

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 ‘Lay Vessel’

Support Name

X Coordinate (m)

Y Coordinate (m)

Z Coordinate (m)

Tensioner

4.8

128.0

0

V-Rollerbox

4.7528

115.8

0

V-Rollerbox

4.7528

103.6

0

V-Rollerbox

4.7528

91.4

0

V-Rollerbox

4.7528

79.2

0

V-Rollerbox

4.7528

67.0

0

V-Rollerbox

4.7528

54.8

0

V-Rollerbox

4.7528

42.6

0

V-Rollerbox

4.7528

30.4

0

Radii of Curvature are also 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 ‘Lay Vessel’ 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 ‘Lay Vessel’

Radius of Curvature (m)

Y Coordinate (m)

Analysis Optimisation

250

60.4

No

150

8.4

No

To complete the definition of the Vessel component, the Vessel Motion component ‘Lay Vessel RAOs’ is associated with the vessel by selecting it from the Vessel Motions drop-down list.

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Vessel Motion Component

The Vessel Motion component is used to specify the dynamic motions of a vessel, including first order (RAO) motions and second order (drift) motions. This example contains a Vessel Motion component named ‘Lay Vessel RAOs’, which is created in the Vessel folder. The vessel motion option RAO + Drift is selected from the Motion Type drop-down list. The RAO file included in the example directory, Lay Vessel.rao, is loaded into the component through the RAO File dialog. These RAOs are supplied in the MCS Kenny format, so the remaining options are left unchanged.

To view the RAO data, you can generate a PipeLay RAO Report by selecting Yes on the Plot RAOs drop-down list. This RAO Report contains graphs of the RAO and phase angles for each of the translational and rotational DOFs for the vessel. The Heave RAO plot is included in the figure below as an example.

Heave RAOs for Lay Vessel

Heave RAOs for Lay Vessel

Seabed Component

A single Seabed component is created in the Model folder and is named ‘Rigid Seabed’. The default properties of a rigid seabed, with a zero coefficient of friction in the longitudinal and transverse directions and a slope of zero degrees, are left unchanged.

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Wave Component

Two Wave components are created in the Load folder. A Wave component, named ‘Regular Wave’, is added to model the regular wave included in this example. The Regular option is selected from the Type drop-down list and the properties of the component are listed in the table below.

Table: Properties of ‘Regular Wave’

Property

Value

Amplitude

2.5 m

Period

8 s

Direction

-180.0°

Phase

0.0°

A second Wave component, named ‘Random Sea’, is added to model the random sea included in the example. The Jonswap – Hs/Tz – Equal Area Discretisation option is selected from the Type drop-down list and the properties of the component are listed in the table below.

Table: Properties of ‘Random Sea’

Property

Value

Wave Height

2.5 m

Up-crossing Period

8 s

Number of Harmonics

50

Dominant Direction

-180 °

 

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