Riflex modeling from scratch

Right click in the browser, select New> RIFLEX Task

Name the task Flex in the wizard

Right click the Flex task and choose Open 3D View to open the graphics view: Zoom in on the the sea surface by clicking in the 3D-view and then using the scroll wheel of the mouse, or (when the mouse cursor is over the 3D graphics) by pressing and holding both the left and right buttons on the mouse and move it away from you. Pan the camera by pressing and holding the left mouse button and (while it is pressed) move it up/down/sideways.

Expand in the folder system browser to the right to see the different parts of the model

Under model folder, and location folder, double click on Flat bottom:
Set position > z to –100 m to create a 100 m water depth.

Double click directly on the location folder:
Set Water Depth to 100 m. This sets the hydrodynamic water depth used to calculate the hydrodynamic forces.

Right click on the model folder and choose New > Support Vessel:
Set name to VESSEL
Include RAO file, rao.inp

Double click on VESSEL to open editor window:
Set initial position to:

Choose Geometry type Geometry file, and select file vessel.hsf
Let all translation/rotation be 0 and scaling in all directions 1

The SIMA workspace should now look like this:

Right click on folder Slender system and create New > Axisymmetric cross section:
Axisymmetric cross section is a description of the cross section defined by outer and inner area of the pipe
Name it RiserCRS

Set the properties of the RiserCRS:
The temperature is set to default. We want this to be 20 degrees. Right click on the default value and chose Set to editable. Set the value to 20
Chose default stress calculation, and set the needed values, calculated from the description:

Set cross section type to Beam and choose No hysteresis
Set stiffness types to Constant and set:

Set Hydrodynamic force coefficients, Input code to Dimensional coefficients. Set:

The rest of the coefficients are zero
Set capacity parameters:

Copy Riser CRS by right click on it an chose copy (or press ctr+c) then right click and chose paste (or press ctr+v)

Rename the new crs elemnent by clicking F2, and enter name BuoyancyCRS

Change the following variables of the BuoyancyCRS
Set Ext. Area to 0.3

Right click on folder Slender system and create New > Supernode
Set name BottomConnection

Set supernode BottomConnection properties
Constraint: Fixed or prescribed
Initial Positions. The initial position always has to be set such that a line is unstretched. One only has to set either global or local position, the other will be calculated:

Static global position:

Rotation = –90
Choose boundary connection: Fix all

Right click on folder Supernodes and create New > Supernode
Set name RiserBase

Set supernode RiserBase properties:
Constraint: Fixed or prescribed
Initial Positions. The initial position has to be set such that a line is unstretched:

Fixed or Prescribed Configuration: Chose Support Vessel: VESSEL
Static global position:

Rotation = –90
Choose boundary connection: Fix all

Right click on folder Slender system and create New > Internal Fluid Type:
Set name fluid_40
Set:

Right click on folder Slender system and create New > Line Type:
Use default name lineType

Set Line Type Properties
Create new segment by clicking the green plus under the segment line. Do this 3 times to create 3 segments
Set the lengths: The Stressfree length should be the same as the length of the segment.

Set the number of elements:

Set the first and last segments Cross section to RiserCRS. The middle segment has cross section: BuoyancyCRS
Set Internal fluid to fluid_40

Right click on folder Slender system and create New > Line:
Set name: Riser
Set properties:

Right click on model and create New > Environment
Set Wave to Numerical Wave:
Press on the upper green plus to add a direction. Set the direction to 0.
Press on the lower green plus to add 4 frequencies. Set the frequencies to:

Add the following spectral values to the last table. This can also be done by copying this table, right click where you want them and chose Import > From clipboard

Set Current to Current
From the table below copy the white part to the clipboard. In the current editor, press the arrow beside the green plus, and chose Create from clipboard. The table is then imported.

Set properties of Static Calculation under Calculation Parameters:
Click on the green plus to add Current forces
Set N Step for the Specified Displacements to 200,
Set max iterations to 20 for volume forces, specified displacements and current forces

Set properties of Dynamic Calculation:
Under Irreg. analysis set time series length to 4096. This combined with the numerical wave settings, leads to a wave with a waveheight of 12.012 m and period of 10 s.
Set simulation length to 72 s with a time step of 3.125e-02 s
Set Node step = 1
Under storage choose Displacement, Force responce, curvature responce and visualization responce.

Set storage step = 8, and file format = Binary. This leads to file output every 0.25 s.
Do this for both Displacement responce storage, force responce storage and curvature responce storage.
Set nodes where you are interested in the results
e.g, if you are interested in the buoyancy part:

Run the simulation
Either double clicking the Initial condition Initial (under the Conditions folder) and click the Run Dynamic button in the editor,or by right clicking Inital (under the Conditions folder) and choose Run dynamic analysis

If you have not opened the graphics view then open it by right clicking RotatingBodies and choose Open 3D View :
In the graphics view there are two drop down menus. The first drop down contains the conditions in the task and will now only show Initial.
The second shows the Modeled state, the Static and the Dynamic results.
Choose the Dynamic simulation (select Dynamic in the second drop down) and click on the play button (the black arrow adjacent to the drop down menus).
You can speed up the simulation result (the animation in the 3D view) by opening the view menu (the small white arrow in the top right corner) and choose Scale playback speed and set it to 10.