Defining a Tensioner
This article summarises the creation of a tensioner for Example 3. It is divided into the following sections:
‘Support Component’ describes the specification of the associated support for the tensioner.
‘Tensioner Component’ describes the specification of the tensioner properties.
Before you proceed to defining the vessel, you need to create a Tensioner component to model the tensioning system on the vessel. First however, you will create a zero-gap guide, using a Support component, to employ in conjunction with the Tensioner component. Note that using a support with a tensioner is optional; however using a zero-gap guide helps ensure that the tensile force of the tensioner always acts in the required direction as the guide prevents the pipe from moving vertically or laterally relative to the tensioner.
Create a zero-gap guide in the Stinger folder by right-clicking and selecting New > Vessel > Support. Rename this support Zero-Gap Guide.
Select Zero-Gap O Support as the Support Type and set the length of the zero-gap guide to 2.0m, as outlined in Example 3, by pressing the Support Properties button and specifying the Support Length. Press OK to confirm the data, the dialog closes, and the Component View is updated as shown in the figure below.
To create a tensioner in the Stinger folder, right-click and select New > Vessel > Tensioner. Rename this new component Tensioner.
The Tensioner component allows you to optionally specify either a tensioner characteristic curve, in order to define the applied tension as function of tensioner payout, or a damping coefficient, which limits the velocity of tensioner payout. These options allow you to simulate tensioner dead band and tensioner on the brake. The application of a characteristic curve or damping coefficient relates to dynamic analyses only - in static analyses the tensioner is assumed to provide a constant restoring tension to restrain the pipeline in the static equilibrium configuration. For this example, where you will be running static stages only, the default constant tension approach, as outlined in Example 3, is sufficient and you may ignore the Characteristic Curve button.
The Tensioner Support drop-down list provides a list of all the Support components currently defined in the project. Select Zero-Gap Guide from the list.
The Component View for the completed Tensioner component is as shown in the figure below.