Project Data Inputs

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Project Data Inputs

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project

Input

Description

Units:

This drop-down list sets the unit system to be employed in the project. The options are Metric (the default) and Imperial.

General:

Click on this button to display the Project Settings dialog. See the ‘Project Settings Dialog section for a detailed description of this dialog.

Constants:

Click on this button to display the Metric Constants or Imperial Constants dialog. See the ‘Metric or Imperial Constants Dialog section a detailed description of this dialog.

Quality Control:

This section contains a set of tick boxes that dictate the quality control procedures adopted by PipeLay for the project. These boxes include:

Results Overwrite Prompt

Re-Run Analysis Prompt

Input Echo

Update Analysis Component Automatically

By default the first three boxes have a tick mark assigned to them while the last box is left unmarked. Refer to ‘Project Component’ for more information.

 

 

Project Settings Dialog

project_settings

Input

Description

Project Title:

The title of the PipeLay project. This input is optional.

Job Number:

A job number for the PipeLay project. This input is optional.

Engineer(s):

The name(s) of the engineer(s) working on the project. This input is optional.

Location:

The location of the project. This input is optional.

 

 

Metric or Imperial Constants Dialog

metric_constants

imperial_constants

Input

Description

Acceleration due to Gravity:

The acceleration due to gravity, g. Defaults to 9.81 m/s2 if metric units are chosen and 32.19 ft/s2 if imperial units are chosen.

Units: [m/s2] or [ft/s2]

Water Density:

The mass density of seawater. This value defaults to 1025.0 kg/m3 metric and 1.9876 slugs/ft3 imperial.

Units: [kg/m3] or [slugs/ft3]

Water Kinematic Viscosity:

The kinematic viscosity of seawater. This value defaults to 1.3x10-6 m2/s metric and 1.4x10-5 ft2/s imperial.

Units: [m2/s] or [ft2/s]

Maximum Element Length:

The maximum element length in the model. This has a default value of 10m metric, 30ft imperial.

The meshing algorithm in PipeLay is discussed in detail in ‘Project Component’. The Maximum Element Length and Maximum Stinger Element Length parameters allow you some control over the mesh density.

Units: [m] or [ft]

Maximum Stinger Element Length:

The maximum element length in the stinger region. This has a default value of 2m metric, 6ft imperial.

See the description above for Maximum Element Length for more information.

Units: [m] or [ft]

Maximum TD Region Element Length:

The maximum element length in the touchdown region. This has a default of 2m metric, 6ft imperial.

Units: [m] or [ft]

Minimum Length of Touchdown Region:

The minimum length of the touchdown region. This has a default of 0m metric, 0ft imperial.

Units: [m] or [ft]

Contact Ramp:

The ramp length at which PipeLay models contact stiffness for the supports. The default is 0.1m or 0.328ft.

For more information about contact modelling, see Technical Note 5.

Units: [m] or ft]

Contact Power:

The power value PipeLay uses in conjunction with the Contact Ramp to generate the power law contact stiffness curve for the supports. Defaults to 1.5.

For more information, see Technical Note 5.

Optimum Contact Stiffness:

This drop-down list sets the procedure for the determination of default optimum contact stiffness for supports. The options are Largest (the default) and Individual.

For more information, see Technical Note 5.

Pivoting Bed Factor:

The scale factor used by the Pivoting Bed contact modelling option to augment the bending stiffness of elements in proximity to a support contact point. Defaults to 1.2.

For more information, see Technical Note 5.

Inertial Force Diameter:

A drop down list to specify whether element drag (used by default) or buoyancy diameters are to be used during the computation of the added mass and inertia terms in Morison's equation.

See Note (a) and (b).

Non-Linear Props in Quasi-Static:

A drop down list to specify whether to introduce non-linear stiffness properties to the static analysis solution before quasi-static analysis steps are performed. Defaults to No

See Note (c).

 

Notes:

(a)Traditionally, PipeLay has based the calculation of added mass and inertia loading on drag diameter, and this behaviour is retained as the default in order to maintain compatibility with earlier versions. However, strictly speaking, the added mass and inertia terms should be based on displaced volume (i.e. buoyancy diameter) as opposed to projected area (i.e. drag diameter), and the Inertial Force Diameter option facilitates this alternative approach. A note is written in the detailed output file at the bottom of the ELEMENT DRAG AND INERTIA COEFFICIENTS table indicating whether the drag or buoyancy diameter was used in Morison's equations.

(b)For pipe sections both diameters are typically very similar, however for stinger sections and structures there can be noticeable differences between the diameters, in which case what diameter actually gets used in Morison’s equation is important. Note that on a strict theoretical level the buoyancy diameter is the more appropriate for Morison’s equation.

(c)This option allows the user to introduce non-linear material properties in a non-linear static step before any quasi-static analysis is performed. For more information on the different static analysis steps refer to the Static Analysis Procedure in Technical Note 3. Note that this option has a limited application and is used mainly for articulated stinger models that have non-linear flex joints whose  moment-angle curves are intended to apply a certain pre-load buoyancy moment to the stinger.