Attachments: Stiffeners

Stiffeners are attachments to a line intended for use in modelling bend stiffeners. Each stiffener has properties determined by a named stiffener type. The stiffener types are defined on the attachment types form and have the following data:

Name

Used to refer to the stiffener type.

Line type

The physical properties of the stiffener are those of the nominated line type. Usually this will be a profiled homogeneous pipe.

Because the stiffener properties are included in addition to the protected line properties, this line type should specify only the properties of the stiffener.

Length

Defines the length of the stiffener. If the line type is profiled then the length is determined by the profile data and so cannot be edited here.

Connection arc length, relative to

Defines the point on the stiffener which corresponds to the protected line attachment position. This correspondence is illustrated here for a stiffener length of 10:

Protected line attachment arc length	Stiffener connection arc length	Protected line protected arc length range
0	0	0-10
5	0	5-15
10	5	5-15
50	10	40-50

For a bend stiffener at end A of a line the connection arc length would set to 0 relative to end A. Similarly for a bend stiffener at end B of a line the connection arc length would set to 0 relative to end B.

Axial load/inertia transfer

Defines the way in which the axial loads and axial inertia are transferred from the stiffener to the protected line.

at connection point means that the axial loads and axial inertia for the entire stiffener line are transferred to the protected line at the connection point, appropriate when you wish to neglect the axial effects of friction due to contact between protected line and stiffener.
over full length means that the axial loads and axial inertia are transferred and shared along the full length of the stiffener. If the contact friction means that the protected line effectively carries the axial loads and inertia of the stiffener then this mechanism is the most suitable.

For a stiffener which is connected to the protected line by means of a full length friction grip, e.g. a Cumberland Grip, then you should use the over full length option for axial load/inertia transfer.

More technical details of axial load/inertia transfer are given in the topic modelling bend stiffeners.