SIMO modeling from scratch in SIMA

Create a new SIMO Task by right clicking in the navigator and choose SIMO Task
Name the task RotatingBodies in the wizard.
Expand the task by selecting the RotatingBodies task in the navigator and click the plus icon in the upper right corner of the navigator.

Right click the RotatingBodies 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.

Right click the Model folder and choose New > Body.
Name the body DISC in the wizard.
The body just created will give an error annotation stating that it has no mass.

SIMA should now look similar to this: image::RotatingBodies.png[image]

Create mass for the body by right clicking the body and choose New > Structural Mass
The Structural Mass editor opens automatically and you can set the needed values:

Change the DISC body into a cylinder
Double click the DISC body in the navigator to open the body editor.
In the Geometry section set type to Cylinder Z.
Change the dimensions of the cylinder:

Create two body points which will act as connection points on the DISC body by right clicking the DISC body and selecting New > Body Point
Name the first body point DISCpoint_1 in the wizard.
The body points list editor will automatically open where you can create the next body point by clicking the green plus icon under the table.
Both points are connected to the origo of the DISC body, so leave x, y and z to 0.

Create two winches connected to these body points by right clicking the DISCpoint_1 body point and choose New > Winch
You will find the body point to right-click on, in the navigator tree, under RotatingBodies > Model > Bodies > DISC > Body Points.

Name the winch WINCH_1 in the wizard.
Set the needed values:

Create an interval item by clicking the plus icon and set these values:

To create the winch for the other body point select the newly created winch in the navigator and copy it (press Ctrl+C).
Select the DISCpoint_2 body point and paste the winch (press Ctrl+V).

The body needs a specified moment to be able to turn around itself
Right click the DISC body and choose New > Specified Moment.
Name it DISC_M1 in the wizard.
Set the needed values:

Create the first of the two bodies that will act as arms on the DISC body by right clicking the Bodies folder and choose New > Body
Name it MOVING1 in the wizard.
Set the following values:

In the geometry section set the following values:
Type = Sphere (this will enable the below mentioned fields)
Radius = 2
Color = Green (Click in the coloured field and select a color different from the default red)

Since the MOVING1 body needs mass create it by right clicking the MOVING1 body and choose New > Structural Mass

Set Mass = 1

The MOVING1 body needs linear damping in heave
Create it by rigth clicking the Kinetics folder under the MOVING1 body and choose New > Linear Damping.
Set the Heave / Heave value to 5.

Create a body point (to act as a connection point) on the MOVING1 body by right clicking the body and choose New > Body Point
Name it MOVING1_point in the wizard.

Create the second body to act as an arm on the DISC body as a copy of the MOVING1 body by double clicking the Bodies folder (in the navigator) and click the plus icon in the Bodies editor that appears
Change X to –20 on the MOVING2 body that we just created.

Create two simple wire couplings to keep the DISC and the MOVING1 and MOVING2 bodies connected
Right click the Model folder and choose New > Simple Wire Coupling.
Name it Wire1 in the wizard.

Set the following values in the Simple Wire Coupling editor that automatically appears:

Create the second simple wire coupling by copying the Wire1 model element:
Select the Wire1 simple wire coupling in the navigator and press Ctrl+C and the Ctrl+V.
Double click the new Wire2 simple wire coupling to edit values in it.
Set the following values:

Create two docking cones to connect the MOVING1 and MOVING2 bodies to the DISC body and characterise the behaviour at different distances between them
Right click the Couplings folder and choose New > Docking Cone.
Name it D_HOR1 in the wizard.
Set the following values in the Docking Cone editor:
The docking pin point Body = MOVING1
The docking cone point body = DISC
The docking cone point Direction X = 1
The docking cone point Direction Z = 0

Cross section values:

We need to create two cross sections each with three characteristics items to model the cone shape.
Create the first cross section by clicking the plus icon under the cross section table hader.
Create the first characteristics item for this cross section by clicking the plus icon under the characteristics table header.
Create the second characteristic item and change the following values:

Create the third characteristics item and change Force to 1000.

Create the second cross section by clicking the plus icon under the cross section table.
Set Axial Distance to 50.
The characteristics are automatically copied from the first cross section and does not have to be changed.

Create the second docking cone by copying and pasting the D_HOR1 docking cone (Ctrl+C and Ctrl+V on the D_HOR1 model element in the navigator).
Change the following values (after double-clicking it in the navigator to open it’s editor):
Docking pin point Body = MOVING2
Docking cone point Direction X = –1

Change the parameters for the static calculation by double-clicking Static Calculation (under the Calculation Parameters folder)
Remove the check in the Calculate equilibrium check box to avoid equilibrium calculations.

Change the parameters for the dynamic calculation by double-clicking Dynamic Calculation (under the Calculation Parameters folder) and change the following values in the Numerical procedure section:

Write visualization file = yes (check the check box in the Storage tab)

Run the simulation
Either double click the Initial condition Initial (under the Conditions folder) and click the Run Dynamic button in the editor,
or right click 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
Select the DISC body in the navigator, right click it and choose Fly to selection.
Zoom out a little bit by pressing (and holding) both the right and left buttons on the mouse and drag it towards you.
You can also zoom by using the scrolling wheel on the mouse if you want to scroll faster in or out.

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.

As you play back the result you may observe in the lower right corner of the graphics view an information box where the time step and other useful information is displayed.

You may observe the model without the body graphics by clicking the Hide body geometry icon in the top right of the graphics editor (hover the mouse pointer over the buttons to read their names/descriptions).
Now you may zoom in to take a closer look at the graphical representation of other elements in the model.