workshop9 msc satellite in orbit

SINDA for Patran Workshop 9 1

Sinda for Patran Satellite in Orbit

Workshop 9

Level: Intermediate

Software Requirement: Sinda for PATRAN THERMICA v4.5.3

Objectives:

Satellite modeling

Trajectory set up

Kinematic (attitude) set up

Mission setup

Processing setup

2

Corporate

MSC.Software Corporation

4675 MacArthur Court

Suite 900

Newport Beach, CA 92660

Telephone: +1 714 540 8900

Europe, Middle East, Africa

MSC.Software GmbH

Am Moosfeld 13

81829 Munich, Germany

Telephone: +49 89 431 98 70

Asia Pacific

MSC.Software Japan Ltd.

Shinjuku First West 8F

23-7 Nishi Shinjuku

1-Chome, Shinjyku-Ku

Tokyo 160-0023, JAPAN

Telephone: +81 3 6911 1200

Worldwide Web www.mscsoftware.com

SINDA for Patran Workshop 9

December 2013

MSC.Software Corporation reserves the right to make changes in specifications and other information contained

in this document without prior notice.

The concepts, methods, and examples presented in this text are for illustrative and educational purposes only, and

are not intended to be exhaustive or to apply to any particular engineering problem or design. MSC.Software

Corporation assumes no liability or responsibility to any person or company for direct or indirect damages

resulting from the use of any information contained herein.

User Documentation: Copyright © 2013 MSC.Software Corporation. Printed in U.S.A. All Rights Reserved.

This notice shall be marked on any reproduction of this documentation, in whole or in part. Any reproduction or

distribution of this document, in whole or in part, without the prior written consent of MSC.Software Corporation

is prohibited.

This software may contain certain third-party software that is protected by copyright and licensed from

MSC.Software suppliers.

MSC, MD, MSC Nastran, MD Nastran, Patran, MD Patran, MSC Sinda, the MSC.Software corporate logo, and

Simulating Reality are trademarks or registered trademarks of the MSC.Software Corporation in the United States

and/or other countries.

NASTRAN is a registered trademark of NASA. I-DEAS is a registered trademark of UGS Corp. or its subsidiaries in the United States and/or other countries. SIND*V2013*Z*Z*Z*DC-OPS-PDF


Problem 1

Satellite in Orbit Geometry Description: We will use a simple model to show how Sinda simulates the satellite thermal analysis. The satellite geometry is as follows:

1 m

2 m1 m

1 m

0.5 m

2.5 m2 m

Y

System

reference frame

origin

1.25 m

2 m

1 m

gaps : 0.1 m

Parabola :

diam=1.5 m

height = 0.25 m

1.75 m

Cylinders :

diam = 0.02 m 1 m

4

Material Description: The following drawing shows the object material specifications:

Material List

Material name Density (kg/m3) Specific mass (J/K/kg) Conductivity (W/K/m)

ALU6061 2700 940 167

HONEYCOMB 50 945 11.5

Coating List

Coating name Emissivity () Absorptivity ()

BLACKPAINT 0.9 0.95

WHITEPAINT 0.81 0.25

MLI 0.71 0.52

SOLARCELL 0.82 0.74

Y

PANELS

Material : HONEYCOMB

Sun face : SOLARCELL

Anti-Sun face : BLACKPAINT

BODY FACES

Material : ALU6061

Inner coating : BLACKPAINT

Outer coating : MLIANTENNA

Material : HONEYCOMB

Emitting face : WHITEPAINT

Rear side : MLI

YOKE

Material : ALU6061

Coating : MLI

Thickness : 0.01

Thickness : 0.001

Thickness : 0.002

Thickness : 0.01


Trajectory Description: Reference line: Earth Altitude: 1000 km Inclination: 60° Solar time of ascending node: 16:00 Epoch: Spring 2000

6

Kinematics Description: System reference: -Z toward Earth +X along Velocity vector Moving parts: Solar arrays –Z pointing toward Sun. Y axis of rotation


Suggested Exercise Steps:

Create a new database and name it satellite1.db

Create rectangular surfaces of satellite body

Reverse some surface normal directions

Create the parabolic surface for the antenna

Create rectangular surfaces of solar panels

Mesh the antenna surface

Mesh the satellite body and solar panel surfaces

Specify Isotropic materials

Specify Coating materials

Specify a MLI material

Define 2D Shell properties

Apply radiation enclosure loads

Perform the Steady State Analysis

Check the models Thermica v4

Create a new Trajectory in Thermica v4

Create a new Kinematics in Thermica v4

Modify the Mission in Thermica v4

Run radiation model in Thermica v4

Display radiation results in Thermica v4

Quit Thermica v4 and continue Sinda running

Import the .nrf result file back into Patran

Display the Steady State Result

Examine Input and Result files

8

Perform the Transient State Analysis


Display the Transient State Result

Plot temperature curves in Thermal Studio

Save the model as satellite2 and quit Patran


Exercise Procedure:

1. Create a new database and name it satellite1.db File/New…

File name: satellite1.db

OK

Tolerance: Based on Model

Analysis Code: MSC Sinda

Analysis Type: Thermal

OK

2. Create rectangular surfaces of satellite body

Geometry

Action: Create

Object: Surface

Method: XYZ

Vector Coordinates List: <2.5 2 0>

Origin Coordinates List: [-1.25 -1 -0.5]

Apply

Click on the Iso 2 View icon to obtain a 3D view of the rectangular surface. Iso 2 View Click on the Fit View icon and Smooth Shaded icon Fit View Smooth Shade Continue to create surface 2 by the same method.

Vector Coordinates List: <2.5 1 0>

Origin Coordinates List: [-1.25 -0.5 0.5]

10

Apply

Your model should look like the following figure:

Now use the Curve/2 Curve method to generate the rest surfaces.

Method: Curve

Option: 2 Curve

By default, the Auto Execute option is checked.

Auto Execute

Click the top edge of Surface 1 and then the top edge of Surface 2.

Starting Curve List: Surface 1.2

Ending Curve List: Surface 2.2

Surface 3 will be automatically generated. Click the bottom edge of Surface 1 and then bottom edge of Surface 2.



Surface 4 will be automatically generated. Click the left edge of Surface 1 and then the left edge of Surface 2.




Surface 5 will be automatically generated. Click the right edge of Surface 1 and then the right edge of Surface 2.



Surface 6 will be automatically generated. Some surfaces are not shaded for display reasons. You may need to click the Fit View icon again to see all the shaded surfaces.

Fit View


3. Reverse some surface normal directions

Geometry

Action: Show

Object: Surface

Info: Normal

By default, the Auto Execute option is checked.

Auto Execute

Hold the left key and drag a rectangle to enclose the whole model. All the surfaces will be selected into the Surface List data box.

12

Surface List: Surface 1:6

Rotate the model to view the current normal directions of all the surfaces. We need to reverse the normal directions of Surface 1, 3 and 5 so that all the surface top sides face out.

Action: Edit

Object: Surface

Method: Reverse

Click in the Surface List data box, click surface 1, hold the Shift key to click surface 3 and 5.

Surface List: Surface 1:5:2

Apply __

Action: Show

Object: Surface

Info: Normal

Auto Execute

Surface List: Surface 1:6

Click on the Iso 4 View icon to obtain a 3D view of the satellite main body.

Iso 4 View


4. Create the parabolic surface for the antenna

Geometry

Action: Create

Object: P-shape

Click on the Paraboloid icon. Paraboloid

The Diameter in the form is the paraboloid open diameter at p2 which is the second point of the revolution axis. The paraboloid opening diameter = 1.5, and the height = 0.25.

Diameter: 1.5

The Axis of Revolution for a paraboloid primitive surface is defined as P1P2 vector. P1 is the apex point, and P2 is the truncation distance. Here we use the height of the paraboloid.

Axis of Revolution: {[0.75 0 -0.5][0.75 0 -0.75]}

More Geometry input...

Base Truncation Distance: 0.25

Apex Truncation Distance: 0

OK

Apply

14

5. Create rectangular surfaces of solar panels

Geometry

Action: Create

Object: Surface

Method: XYZ

Vector Coordinates List: <2 1 0>

Origin Coordinates List: [-1 1.75 0]

Apply

Repeat the above operations to create the other 7 solar panels. Since all the solar panel sizes are the same, we do not need to change vector in the Vector Coordinates List data box. We just need to adjust coordinates in the Origin Coordinates List data box. Please note: the gap distance between the solar panels is 0.1.


Apply


Apply


Apply

Origin Coordinates List: [-1 -2.75 0]

Apply


Apply


Apply


Apply



6. Mesh the antenna surface

Elements

Action: Create

Object: Mesh Seed

Type: Uniform

Number of Elements

Number = : 6

Auto Execute

Click on the View Corners icon in the top bar menu.

View Corners

Hold the left key, drag a rectangle to include the paraboloid surface of the antenna. We will have a zoomed view of the antenna surface.

Click on the paraboloid radius edge, with Auto Execute on, the mesh seeds will automatically show up.

Curve List: Surface 7.1 (or 7.3)

Number = : 20

Click on the circular edge of the paraboloid surface.

16

Curve List: Surface 7.2

Now mesh the paraboloid surface.

Object: Mesh

Type: Surface

Elem Shape: Quad

Mesher: IsoMesh

Topology: Quad4

Click in the Surface List data box, then pick the paraboloid surface.

Surface List: Surface 7

Apply

Equivalence the coincident nodes on the paraboloid surface.

Action: Equivalence

Object: All

Type: Tolerance Cube

Equivalencing Tolerance: 0.005

Apply

SINDA for Patran Workshop 9 17 Click on the Fit View icon and Iso 1 View icon to obtain a 3D view of the satellite main body. Fit View Iso 1 View


7. Mesh the satellite body and solar panel surfaces

Elements

Action: Create

Object: Mesh

Type: Surface

Elem Shape: Quad

Mesher: IsoMesh

Topology: Quad4

Click in the Surface List data box, then hold the Shift key to pick all the satellite body and solar panel surfaces. You may need to rotate the model for a better view to pick the surfaces.

Surface List: Surface 1:6 8:15

Global Edge Length: 0.444444

18

Apply


Now equivalent the coincident nodes.

Action: Equivalence

Object: All

Type: Tolerance Cube

Equivalencing Tolerance: 0.005

Apply

8. Specify Isotropic materials

Materials

Action: Create

Object: Isotropic

Method: Manual Input

Material Name: alu6061


Input Properties...

Thermal Conductivity = 167

Specific Heat = 940

Density = 2700

OK

Apply

Material Name: honeycomb

Input Properties...

Thermal Conductivity = 11.5

Specific Heat = 945

Density = 50

OK

Apply

9. Specify Coating materials

Materials

Action: Create

Object: Coating


Material Name: blackpaint

Input Properties...

IR Emissivity = 0.9

UV Absorptivity = 0.95

OK

Apply

Material Name: whitepaint

Input Properties...

20

IR Emissivity = 0.81


OK

Apply

Material Name: solarcell

Input Properties...

IR Emissivity = 0.82


OK

Apply

10. Specify a MLI material

Materials

Action: Create

Object: MLI


Material Name: mli

Input Properties...

External IR Emissivity = 0.71

External UV Absorptivity = 0.52

Overall E-Star = 0.02

OK

Apply

11. Define 2D Shell properties

Properties

Action: Create


Object: 2D

Type: Shell

Property Set Name: antenna

Input Properties...

Material Name: m:honeycomb

Thickness: 0.01

OK

Select Application Region

Verify the Surface or Face icon is checked. Surface or Face

Select Members: Surface 7

Add

Apply

Property Set Name: body

Input Properties...

Material Name: m:alu6061

Thickness: 0.002

OK

Clear the Application Region first, then select new surfaces.

Select Members: Surface 1:6

Add

Apply

Now we will create two shell properties for the solar panels. In the Mission tab, the elements are grouped by the property names. We want the two solar panels have separate kinematics.

Property Set Name: solar_panels_py

Input Properties...

22


Thickness: 0.01

OK



Add

Apply

Property Set Name: solar_panels_ny

Input Properties...


Thickness: 0.01

OK



Add

Apply

12. Apply radiation enclosure loads

Loads/BCs

Action: Create

Object: Radiation(Sinda)

Type: Element Uniform

Option: Enclosures

New Set Name: antenna_top

Target Element Type: 2D

Input Data...

Surface Option: Top


Form Type: Input Material

Top Surf Material: m:mli

Enclosure ID: 1

Small Facets Method

OK

Select Application Region...

Geometry Filter: Geometry

Verify the Surface or Face icon is checked. Surface or Face

Select Surfaces or Edges: Surface 7

Add

OK

Apply

New Set Name: antenna_bottom

Input Data...

Surface Option: Bottom

Bottom Surf Material: m:whitepaint

OK


Select Surfaces or Edges: Surface 7

Add

OK

Apply

New Set Name: body_top

Input Data...

Surface Option: Top

24

Top Surf Material: m:mli

OK


Select Surfaces or Edges: Surface 1:6

Add

OK

Apply

Now we create the radiation load on the body inside surfaces. We use enclosure id =2. Later we will use SindaRad to calculate the view factors for the enclosure 2, while use Thermica v4 to calculate the view factors and orbital fluxes for the enclosure 1.

New Set Name: body_bottom

Input Data...


Top Surf Material: m:blackpaint

Enclosure ID: 2

OK



Add

OK

Apply

New Set Name: panel_top

Input Data...

Surface Option: Top

Top Surf Material: m:blackpaint

Enclosure ID: 1

OK




Add

OK

Apply

New Set Name: panel_bottom

Input Data...


Bottom Surf Material: m:solarcell

OK



Add

OK

Apply

26

13. Perform the Steady State Analysis

Analysis

Action: Analyze

Object: Entire Model

Method: Translate and Run

Job Name: satellite1

Thermal Solution Setup...

Multiple Radiation Enclosures

Verify that Enclosures is checked under Available Enclosure and Radiation Loads.

Enclosures

Click the Enclosure ID 1 –-- antenna_top in the top list box.

Available Enclosures and First Loads: Enclosure ID 1 ---- antenna_top

Enclosure ID: 1

Input an enclosure name in the Enclosure Name data box. This is optional, just provides more description to this enclosure.

Enclosure Name: outside

We will use Thermica v4 to calculate the view factors and orbital fluxes.

THERMICA V4_

Check the Orbital Option to make the orbital heat fluxes available.

THERMICA Option Setup: Orbital Option

Solar/Planetary Flux/RADK

THERMICA V4 Advanced Parameters_

Event Computation Method: Anomaly Step

True Anomaly Step: 10.0

OK

Change the REF Distribution Method from FULL to AREA. This is required by Thermica for the moving parts (such as solar panels).

REF Distribution Method: AREA

OK


Create

You will see the “1, outside , active” is displayed in the Existing Customized Enclosures list box. These setups will not affect other enclosures.

Close

Check the Default Radiation Enclsoure. Those enclosures which are not specially defined in the Multiple Radiation Enclosures will use the parameters defined in the Default Radiation Enclsoure form.

Default Radiation Enclosure

By default, SindaRad is the default radiation solver.

SindaRad (Default)_

Check the SindaRad Method, RADK method is the default option.

SindaRad Method: Compute RADK Network

OK

OK

Pick the Double Precision as the Sinda solver option.

Sinda Option: Double Precision

OK

Apply

Translator will run the default enclosure first. You will see a SindaRad window pops up, and then close quickly. It shows satellite inner body model (Enclosure ID =2) and the model is rotating. By default, SindaRad runs automatically unless you choose the interactive option. After SindaRad running, Thermica v4 will run the customized enclosure (Enclosure ID =1) defined in Multiple Radiation Enclosures form. The Thermica V4 GUI will pop up and looks like the following figure.

28

14. Check the models in Thermica v4 Under the Modeler tab, you can check the Material, Model, and Meshing.

Hold and drag your left mouse on the screen, you can rotate your model in the 3D View. Hold and drag your middle mouse on the screen, you can drag your model in the 3D View. Hold and drag your right mouse on your screen, you can zoom in/out your model.

Modeler Meshing

You may notice the Thermica model name is satellite1_1. Here “_1” is automatically added for the radiation enclosure ID = 1 defined in Multiple Enclosures form. In multi-enclosure radiation models, the name is created by taking the base job name and adding the “_N” suffix, where N is the user-assigned enclosure ID. The default enclosure receives a “_0” suffix, so it is satellite1_0 for the SindaRad enclosure ID = 2 in this model. There are some rules for the names of the multiple enclosure radiation models. Please reference Sinda for Patran User’s Guide/Chapter 8 for more details.

15. Create a new Trajectory in Thermica v4 Click the Trajectory tab to switch to Thermica v4 Trajectory window.

Trajectory

Create a new Trajectory. Click File, and then pick the New.

File/New

SINDA for Patran Workshop 9 29 The New Trajectory browser and graphics window show up. Right click the Trajectory, then click Edit. The New Trajectory edition form pops up.

Trajectory (right click mouse) Edit

Click the Sun in the Celestial bodies window, then click Select button, add the Sun into the window on the right side.

Sun

Select

Apply

Close

In the graphical window, we should be able to see both of the Sun and Earth. We can turn on the Eclipse cones option so that we can see the Sun position easily. At the lower left corner of the graphics window, click the Configuration View icon, the Configuration window will pop up.

Configuration View

In the Configuration window, click Display, then check on the Eclipse cones option.

Display

Celestial bodies: Eclipse cones

Close

The gray eclipse cone shows up. You can rotate the Earth to find the Sun at the opposite direction of the eclipse cone.

30

Now set up the trajectory parameters for the general keplerian orbit. Right click the Arcs, then click Create arc, click General keplerian. The New Trajectory edition form pops up.

Arcs (right click mouse) Create arc General keplerian

In the New Trajectory edition form, input the following parameters:

Orbit reference: Earth

Semi major axis: 7371

Ascending node definition: True solar time

Ascending node solar time: 16:00:00.000

Inclination: 60

Anomaly: 0

Reference date: Earth season date

<Spring equinox>: 2012

Start: Earth season date


Apply


Close

Now rotate the Earth and orbit, the Trajectory window looks like the following figure: You can run the trajectory to see how the satellite moves along the orbit by clicking the triangle play icon. You can display the text information by setting up the Entities Configuration in the Configuration View window. You can also view the ground track for a given trajectory. On the top menu, click View, then select Add, Ground tracks view, A Ground tracks view will be added. View/Add/Ground tracks view

At the lower left corner of the Ground tracks view, click the Configuration View icon,

Configuration View In the pop up Ground tracks view configuration window, under Entities configuration, first you need to load the trajectory into this view.

Entities configuration

Load

Close

The Ground tracks view should look like the following figure.

32

If your trajectory has multiple revolutions, you can display multiple rotation curves or single rotation curve. This is controlled by the Display option in the Ground tracks view configuration window. Close the Ground tracks view window by clocking the close icon at the up-right corner, or View/Close/ Ground tracks view (#). Save the trajectory file. Please note: the Files of type should be .systri. File/Save as…

File Name: satellite1_1

Save

16. Create a new Kinematics in Thermica v4 Click the Kinematics tab to switch to Thermica v4 Kinematics window.

Kinematics

Create a new Kinematics. Click File, and then pick the New.

File/New

The New Kinematics browser and 3D view graphics window show up. In the 3D view window, the red X, and white (later becomes blue) Y, Z are the three axes of the body coordinate system. It is the same as that in Patran and MSC Thermica v4 Modeler window. Let’s first define a Kinematics for the satellite body. Double click the Kinematics. The New Kinematics edition form pops up.


Kinematics (double click)

In New Kinematics edition form, check the very top data box, you should find Kinematics. This is default name of the main kinematics for the main body of the satellite. You can change the name if you want. Here we will keep this default name. Select the Orbit planet reference option for the first Multiple laws – Default phase:

Multiple laws: _Orbital planet reference

Let -Z coordinate direction of the model pointing to the Earth (the antenna points to the Earth):

Pointing vector:

X: 0

Y: 0

Z: -1

Input the Orbit velocity vector for the second Multiple laws:

Multiple laws: Orbit velocity vector

Let X direction of the model points to the orbital velocity:

Pointing vector:

X: 1

Y: 0

Z: 0

Apply

Close

Now let’s define Kinematics for the solar panels. Actually we can use one Kinematic for the two panels because they all rotate around the same Y axis. Here we define two Kinematic links to show how to define multiple Kinematics based on the geometry points on the model. Right click the main Kinematics, in the pull down menu, go to the following options. Kinematics (right click) Create kinematic body In Pivot (1 dof)

In New Kinematics edition form, check the very top data box, you should find the New Pivot (1 dof). This is the new Kinematic name, change it to solar_panels_py. (py as positive Y)

34

solar_panels_py The solar panels rotate around Y axis.

First rotation:

Axis: Y

Click the Modeler Tab in the Thermica main window, and then click the Model Tab.

Modeler

Model

In the 3D view window, right click your mouse, you will see a menu. Click the Help items option, then pick the Create middle… option.

Right click mouse on 3D view Help items Create middle…

Now hold the Alt key to pick the two corner points of the solar panel on the +Y side, the middle point will be generated with a green X sign. Alt + left mouse pick (twice on two corners)

Hold the Alt key and click on the middle node, you will see the coordinates displayed below the 3D view window. They are automatically copied and you can put them later in other Thermica windows.

SINDA for Patran Workshop 9 35 Now back to Kinematics tab, you will see the New Kinematics edition form shows up again with the kinematic name: solar_panels_py

Kinematics

Click Add button after the ORIGIN, then select One point translation.

Add

One point translation

Keep Point 1 as it is, and then copy the middle point generated above into the Transform 1.

Point 1:

X: 0

Y: 0

Z: 0

Click the icon at the right side of Transform 1, the coordinates of the middle point will be automatically copied into the X,Y,Z data boxes.

Clcik of the Transform 1

Transform 1:

X: -2.98023228317845e-09

Y: 1.75

Z: -0.000605

Apparently there are some mini errors caused by middle point generation. If you want, you can manually correct these coordinates.

Transform 1:

X: 0

Y: 1.75

Z: 0

Click Add button at the right side of KINEMATIC LAW – Default phase, then select Sun in the pull down menu.

Add

Sun

Select the -Z direction to point to the Sun.

36

Sun/Pointing vector:

X: 0

Y: 0

Z: -1

Apply

Close

Follow the same steps above to create another kinematic link for the solar panels on the –Y side with a kinematic name as solar_panels_ny (ny as negative Y). Select Y as the rotation axis. You can create another middle point or directly input the coordinates as follows.

Transform 1:

X: 0

Y: -1.75

Z: 0

Also select the -Z direction to point to the Sun. Right click in the 3D View window and select Fit all option.

Right click mouse on 3D view Fit all

You can find three coordinate systems in the 3D view. The one in the middle is for the whole satellite body. The other two are for the two solar panels respectively.

SINDA for Patran Workshop 9 37 You can right click on the 3D view window, select Test trajectory, then select Custom trajectory, and then satellite1.systrj, you can view the kinematics animation. At the bottom of the 3D view, a set of buttons allows the animation to be run. The yellow arrows indicate the aimed directions of two kinematic laws, and are labeled with the kinematic law names.

Right click mouse on 3D view Test trajectory Custom trajectory satellite1.systrj

This will run the kinematics along the selected trajectory. The main kinematic does not move, while two other kinematics for the solar panels rotating around Y axis, their Z axes trying their best to point to the Sun. You can see the solar panels do not face the sun quite well. The main kinematic law is strictly obeyed, but the second kinematic laws have a relatively lower priority. The antenna is always straightly facing to the Earth. The solar panels’ pointing is restricted by the fixed rotation axis. The following figure shows the kinematics running on the trajectory.

Remove the kinematic animation. Right click mouse on 3D view Test trajectory Disabled

Save the Kinematic file. Please note: the Files of type should be .syskin.

File/Save as…


Save

38

17. Modify the Mission in Thermica v4 Click the Mission tab to switch to Thermica v4 Mission window.

Mission

Translator automatically created a sysmis file as a default. You can edit this existing mission to meet your requirements.

Double click the Mission. In the Mission form,

Mission (Double click)

You can see the .sysmdl and .sysmsh files are referenced. We are going to add the newly created .systrj and .syskin files to this mission by clicking Add button, then <Select a file>.

Trajectory: satellite1_1.systrj

Kinematic Model: satellite1_1.syskin

TrueAnomalyStep: 10 __ ___

Please note: Under Variables, we can setup the Thermica variables: TrueAnomalySetup and TimeStep. Thermica may use either TrueAnomalySetup or TimeStep to setup the computation events (orbital intervals). It depends on which method is used. In our situation, we choose the anomaly step option in Step 13. So the TrueAnomalySetup variable is used here. The CompPtAtEnd variable is for the Eclipse and Penumbra points. If you want, you can modify the event computation method under the TimeLine by double click the Computation evenet rule(1). Please note: After editing under the Timeline tree structure, the Mission becomes inactive by some reasons. If you want to edit the Mission again, you may need to click one of the items in the Geometry tree structure, the Mission is active again.

Apply

Close

In the Browser/Geometry tree structure, double click the solar_panels_py.

solar_panels_py (double click) In the New Mission edition form, check the Add after KINEMATIC LINK,

Add

Check on solar_panel_py to assign this kinematics to the solar panels at the +Y direction.

solar_panel_py

Apply

Close

SINDA for Patran Workshop 9 39 Double click the solar_panels_ny.. The New Mission edition form pops up.

solar_panels_ny (double click)

In the New Mission edition form, check the Add after KINEMATIC LINK,

Add

Check on solar_panel_ny to assign this kinematics to the solar panels at the -Y direction.

solar_panel_ny

Apply

Close

You do not have to link the kinematics for the antenna and body. By default, they are linked to the main kinematics which –Z points to the Earth, and +X along with the Velocity direction.

Right click in the 3D View window, and then click Fit, and Trajectory,

Right click mouse on 3D View Fit Trajectory

You should be able to see the model and orbit as the following figure:

At the lower left corner of the 3D view, click the Configuration View icon,

Configuration View

40

In the pop up 3D view configuration window, under Display, change the model scale to the Large model, check on Eclipse cones.

Display


Model scale: Large model

The Configuration view will be automatically closed. This sometimes may cause the Earth disappear in the 3D view. You can go back to Configuration view to change some options back and forth to refresh the 3D view, and then close the Configuration view. Right click in the 3D View window, then click Camera lock in, and select Earth inertial frame,

Right click mouse on 3D View Camera lock in Earth inertial frame

Rotate the model so that you can see the model and the eclipse cone. You can run the mission by clicking the triangle play icon at the lower left corner of the 3D view window. You can monitor the Bata angle of the orbit, and the current True Anomaly of the solar panels which shows the deviation of the solar panels facing to the Sun. At the lower left corner of the 3D view, click the Configuration View icon,

Configuration View

In the pop up 3D view configuration window, under Entities configuration, change to Textual information tab; check on Beta Angle, and True Anomaly.

SINDA for Patran Workshop 9 41 Entities configuration Textual information

Beta angle

True Anomaly

Close

You can run the mission by clicking the play button (triangle) at the lower right corner of the 3D view window. You will see how Beta angle and True Anomaly change with the orbit. You can view the satellite and solar panels closely by using the Camera lock in Local orbital frame. The Local orbital frame is actually the default option.

Right click mouse on 3D view Camera lock in Local Orbital frame

Adjust the 3D View to have a bigger view on the satellite and solar panels, and run the mission. Monitor the solar rotation and Sun shine on the satellite body. Please note: you may need to click the button to set the orbital back to the initial position.

Right click in the 3D View window, and then click Fit, and Trajectory, Right click mouse on 3D View Fit Trajectory

42

Save the mission file. Please note: the file is an existing file created by the translator. You do not need to use the Save as… option.

File/Save

18. Run radiation model in Thermica v4

Processing

Click Run icon (pointed by the red arrow in the above picture).

Run 4

Answer Yes for the pop up window to save the processing diagram

Yes

A Process run window pops up to show the running status. By default, the Mission, Radiation, Solar Flux, and Planet Fluxes options are checked. Click Run icon again.


Run

After running, you should see the “Result files have been loaded” at the end of the status messages. Check the running status. Make sure there are no errors messages, and then close it.

Close

You should see the result files are displayed in the Result zone in the Processing window. You can also go to Modeler or Mission tabs to display and view the results if you want. Please reference Workshop 3 / Problem 5 for detailed steps.

44

19. Display radiation results in Thermica v4 Click the Modeler tab to switch to Thermica v4 Modeler window.

Modeler Meshing (click this tab to select it)

Configuration View

Click Entities configuration; make sure only the satellite1_1.sysmsh is displayed in 3D view. You may need to unload the satellite1_1.sysmdl to remove the geometry model. Sometimes both .sysmdl and .sysmsh are displayed in 3D view. The geometry model may cover the mesh if they are both shown. You have to unload the .sysmdl from the 3D view. Under Shape Appearance tab, and click the following items.

Entities configuration Satellite1_1.sysmsh Shape Appearance

Result

satellite1_1

satellite1_1.fs.h5 (fs for solar flux)

Mean Absorbed Solar Flux

Rotate the model as below. The -Z side of the solar panels has more Absorbed Solar Flux.

Now click on satellite1_1.fp.h5.

satellite1_1.fp.h5 ( fp for flux planet )


Earth Albedo Direct Flux

Rotate the model as shown below. The -Z side of the satellite body and antenna has more Earth Albedo Direct Flux. Please note: This value is not a mean flux. It is changing along the orbit. You can run the animation to display the Earth Albedo Direct Flux.

You can also view the results in the Mission window. Click the Mission tab to switch to Thermica v4 Mission window.

Mission

Configuration View

Click Entities configuration; make sure the Meshing is displayed instead of Model. The results are based on the mesh. Under Shape Appearance tab, and click the following items.

Entities configuration Satellite1_1.sysmis Meshing (may need to change from Model) Shape Appearance

Result

satellite1_1


Direct Solar Flux

Rotate the model as shown below. You can run the animation to see the Direct Solar Flux vs orbital time.

46

20. Quit Thermica v4 and continue Sinda running Now we can quit Thermica v4. Sinda for Patran translator will continue to run. The translator will read the Thermica v4 results, along with SindaRad results and other FEM information to generate the Sinda input file.

MSC Thermica/Quit

A pop up window asks if you really want to quit, answer Yes to confirm the quit.

Yes

Some popup windows ask if you want to save some files before closing, always answer No for not to save.

No

The Sinda for Patran translator will continue to run. If you did not change the REF Distribution Method from FULL to AREA, a message window will pop up to tell you that AREA method is forced because there are articulation parts (like the solar panels) in the radiation model. The AREA method is used automatically instead of FULL method. The articulation and FULL method are incompatible. Translator has to use the AREA method dealing with models that have moving parts, so that the time dependent radiation conductors can be used. Answer Yes to close the warning window. Translator will continue to run. You do not have to re-run Thermica or SindaRad every time. By checking “Reuse Existing Results(if exist)” option, you can skip Thermica or SindaRad running. To support this feature, you have to keep the following files in the working directory.

For Thermica v4:

SINDA for Patran Workshop 9 47 jobname.rad.h5 ---- REF jobname.fs.h5 ---- Solar Flux jobname.fp.h5 ---- Planet Flux For SindaRad: jobname.srm ---- REF If you use “Compute Flux in SINDA” option in SINDARad Radiation Solver Setup form, you will need to resue existing results for all enclosures which use SindaRad/Compute Flux in SINDA option. If one of these enclosures does not reuse existing results, SindaRad will rerun for all these enclosures. For “Compute Flux in SINDA”, all these enclosures will share one .srm file. Sinda will continue to calculate the temperature result.

After Sinda has finished running, Patran output window will show Sinda “total run time” at the bottom.

21. Import the .nrf result file back into Patran

Analysis

Action: Access Result

Verify the Job Name is satellite1.


Apply .

In the Patran message window, you should see “Result file Imported into Patran”.

22. Display the Steady State Result

Results

Action: Create

Object: Quick Plot

Select Result Cases: satellite1, steady state

Select Fringe Result: Temperature, Nodal

Click on the Fringe Attributes icon and set up the Display option.

Fringe Attributes

Display: Element Edges

Click on the Reset Graphics icon and Wireframe icon.

48

Reset Graphics Wireframe

Apply

Rotate the model for a better view. Your model should look like the following figure:

23. Examine Input and Result files

Analysis


Edit/Manage Files...

Sinda Input File(.sin)

You can examine the input file and see how the Sinda for Patran translator creates the source data. The translator has automatically calculated the average heat flux based on the orbital heating data arrays which come from the radiation analysis (THERMICA). Close the satellite1.sin file after examination.

24. Perform the Transient State Analysis

Analysis

Action: Analyze





Apply


Transient State Setup

Choose Solution Routine: FWDBKL

You can calculate the orbital period = 6298 seconds in the previous Thermica V4 animation run. You can compare the start time and end time at the animation control pad. Here we will output 40 temperature results for the whole orbit,so the OUTPUT interval is 157.45 seconds.

TIMEND: 6298

OUTPUT: 157.45

OK

Specify Initial Conditions

Sinda Restart Option: Use Previous Results (if available)

OK


Check the current default radiation solver: SindaRad (Default).

SindaRad (Default)_

SindaRad Option Setup: Reuse Existing Results (if exist)

OK

OK


Check the Existing Customized Enclosures: 1, outside, active

Existing Customized Enclosures: 1, outside, active

Check the current selected radiation solver for this enclosure: THERMICA V4 (Selected).

THERMICA V4 (Selected)_

THERMICA Option Setup: Reuse Existing Results (if exist)

Orbital Option

50

Use the default Solar/Planetary Flux/RADK option.


OK

Modify

Close


OK

Output Routine Setup…

Thermal Studio Routines

Thermal Studio Routines: TSOUT_T-output temperature

OK

OK

Apply

Sinda for Patran will use the previous result as the initial temperature, and the existing radiation results will be used, therefore THERMICA and SindaRad will not be called. You can rerun this model again and again for the dynamic thermal balance. You are not limited to make a transient run inside just one orbital period. In the transient analysis, the time dependent heat flux and time dependent radiation conductors will be used when there are moving parts in the model.


Analysis



Apply .

26. Display the Transient State Result

Results

Action: Create

Object: Quick Plot

Select Result Cases: satellite1, Time=6.29800E+03nrf



Apply

The last result case of your model should look like the following figure:

If you want to create an animation display, please reference Workshop 1 for more details.

27. Plot temperature curves in Thermal Studio

Analysis

Action: Thermal Studio


Apply

Right click the Result.0 icon. In the pop up window, click New Plot and input a new plot name.

Result.0 (right click)

New Plot

Name: -Y_Solar_Panel

OK

In the Output Data list box, drag the slide bar down and double click the 396 ---T396, 414---T414, 432---T432, and 450---T450 lines. These nodes are the middle nodes of the four -Y solar panels.

52

These four results will be added into the Plot Data list box. Click OK to plot the temperature curves. You can reference Workshop 5 for more details on how to use Thermal Studio.

OK

The beginning of the curves shows the effect of the initial temperatures from the steady state run. Close Thermal Studio by either click the X or File/Exit. Save the model as satellite2.db for Problem 2

File/Save a Copy…/satellite2.db/Save

To complete this exercise, close the database and quit Patran.

File/Quit…


Problem 2

Multiple Arcs and Pointings Model Description: We will use the same satellite model, but a new orbit and pointing. The new orbit is composed of 3 arcs. Several arcs may be used to define orbital parameter and pointing changes. The first arc has the same orbital characteristics as in Problem 1. Arc #1 Orbital arc:

Name: Sun pointing

Orbit parameters:

Reference line: Sun Altitude: 1000 km Inclination: 60 deg Solar time of ascending node: 16h

Epoch: Spring 2000

Duration: 170 deg Arc #2 Orbital arc:

Name: Sun to Earth Linked with previous: ON

Orbit parameters:

Reference line: Sun Altitude: 1000 km Inclination: 60 deg Solar time of ascending node: 16h True anomaly: 170 deg

Computation steps:

True anomaly steps: ON Value: 1 deg

Duration: 10 deg

Arc #3

Orbital arc:

Name: Earth pointing Linked with previous: ON

Orbit parameters:

Reference line: Sun Apogee: 3000 km Perigee: 1000 km Inclination: 60 deg Solar time of ascending node: 16h Argument of perigee: 180 deg True anomaly: 0 deg

Duration: 180 deg Arc#1

Arc #2

Arc #3

54

The pointing is made of 3 sequences in agreement with the orbital arcs. The sequence #3 is the same as in Problem 1. In sequence #1, the satellite is Sun oriented. In sequence #3 it is Earth oriented. Sequence #2 permits a junction between the two other sequences. It starts from a Sun oriented attitude, and then moves toward the Earth according to an attitude law. When a body is a mobile part in one sequence, it must be specified as a mobile part in every sequence. Sequence #1 Name: Sun pointing

System reference:

-Z toward Sun +Y toward North Pole

Mobile parts:

Solar arrays –Z pointing toward Sun. 1 axis of rotation. Sequence #2 Name : Sun to Earth

System reference:

-Z toward Sun +Y toward North Pole

Attitude law: ON

Angle values :

dYaw/dt = -0.42 deg/s dPitch/dt = 0.14 deg/s dRoll/dt = -0.32 deg/s

Mobile parts:

Solar arrays –Z pointing toward Sun. 1 axis of rotation.

Sequence #3

Name: Earth pointing

System reference:

-Z toward Earth +X along Velocity vector

Mobile parts:

Solar arrays –Z pointing toward Sun. 1 axis of rotation.


Suggested Exercise Steps:

Open the database: satellite2.db

Perform the Steady State Analysis

Check the models in Thermica v4

Create a new Trajectory in Thermica v4

Create a new Kinematics in Thermica v4

Modify the Mission in Thermica v4

Run radiation model in Thermica v4

Display radiation results in Thermica v4

Quit Thermica v4 and continue Sinda running


Display the Steady State Result

Examine Input and Result files

Perform the Transient State Analysis


Display the Transient State Result

Plot temperature curves in Thermal Studio

56

Exercise Procedure:

1. Open the database: satellite2.db

File/Open…

File name: satellite2.db

OK

2. Perform the Steady State Analysis

Analysis

Action: Analyze






Verify that Enclosures is checked under Available Enclosure and Radiation Loads.

Enclosures

Click the Enclosure ID 1 –-- antenna_top in the top list box.

Available Enclosures and First Loads: Enclosure ID 1 ---- antenna_top

Enclosure ID: 1

Enclosure Name: outside

We will use Thermica v4 to calculate the view factors and orbital fluxes.

THERMICA V4_

Check the Orbital Option to make the orbital heat fluxes available.

THERMICA Option Setup: Orbital Option


THERMICA V4 Advanced Parameters_

Event Computation Method: Anomaly Step

True Anomaly Step: 10.0


OK

Change the REF Distribution Method from FULL to AREA. This is required by Thermica for the moving parts (such as solar panels).

REF Distribution Method: AREA

OK

Create

You will see the “1, outside , active” is displayed in the Exsiting Customized Enclosures list box. These setups will not affect other enclosures.

Close

Check the Default Radiation Enclsoure. Those enclosures which are not specially defined in the Multiple Radiation Enclosures will use the parameters defined in the Default Radiation Enclsoure form.


SindaRad (Default)_

Check the SindaRad Method, RADK method is the default option.

SindaRad Method: Compute RADK Network

OK

OK

Pick the Double Precision as the Sinda solver option.


OK

Apply

58

Translator will run the default enclosure first. You will see a SindaRad window pops up, and then close quickly. It shows satellite inner body model (Enclosure ID =2) and the model is rotating. By default, SindaRad runs automatically unless you choose the interactive option. After SindaRad running, Thermica v4 will run the customized enclosure (Enclosure ID =1) defined in Multiple Radiation Enclosures form. The Thermica V4 GUI will pop up and looks like the above figure.

3. Check the models in Thermica v4 Under the Modeler tab, you can check the Material, Model, and Meshing.

Hold and drag your left mouse on the screen, you can rotate your model in the 3D View. Hold and drag your middle mouse on the screen, you can drag your model in the 3D View. Hold and drag your right mouse on your screen, you can zoom in/out your model.

Modeler Meshing

You may notice the Thermica model name is satellite2_1. Here “_1” is automatically added for the radiation enclosure ID = 1 defined in Multiple Enclosures form. In multi-enclosure radiation models, the name is created by taking the base job name and adding the “_N” suffix, where N is the user-assigned enclosure ID. The default enclosure receives a “_0” suffix, so it is satellite2_0 for the SindaRad enclosure ID = 2 in this model. There are some rules for the names of the multiple enclosure radiation models. Please reference Sinda for Patran User’s Guide/Chapter 8 for more details.

4. Create a new Trajectory in Thermica v4

SINDA for Patran Workshop 9 59 Click the Trajectory tab to switch to Thermica v4 Trajectory window.

Trajectory

Create a new Trajectory. Click File, and then pick the New.

File/New

The New Trajectory browser and graphics window show up. Right click the Trajectory, then click Edit. The New Trajectory edition form pops up.

Trajectory (right click mouse) Edit

Click the Sun in the Celestial bodies window, then click Select button, add the Sun into the window on the right side.

Sun

Select

Apply

Close

In the graphical window, we should be able to see both of the Sun and Earth. We can turn on the Eclipse cones option so that we can see the Sun position easily. At the lower left corner of the graphics window, click the Configuration View icon, the Configuration window will pop up.

Configuration View

In the Configuration window, click Display, then check on the Eclipse cones option.

Display

60


Close

The gray eclipse cone shows up. You can rotate the Earth to find the Sun at the opposite direction of the eclipse cone.

Now set up the trajectory parameters for the arc #1. Right click the Trajectory, then click Create arc, click General keplerian. The New Trajectory edition form pops up.

Trajectory (right click mouse) Create arc General keplerian

In the New Trajectory edition form, change the title from New General keplerian to Sun Pointing, then input the following parameters:

New General keplerian: Sun Pointing





Inclination: 60

Anomaly: 0


Reference date: Earth season date


Start: Earth season date


End: Angle

Angle: 170

We will need the END time to define the next arc. We need to save the Calendar date by switch the END time options between Angle and Calendar date.

End: Calendar date

Copy the time under the Calendar date, then switch the option back to Angle, make sure the Angle value is 170. You may need to correct some minor errors.

20/03/2012 05:59:36.522

End: Angle

Angle: 170

Apply

Close

Now follow the same step to set up the trajectory parameters for the arc #2. Change the title name to be Sun to Earth. Input the following parameters:

New General keplerian: Sun to Earth





Inclination: 60

Argument of the periapsis: 0

Anomaly: 170

Reference date: Calendar date

62

Here we will need to input the end time of the previous arc. Paste your saved Calendar date into the data box for the Reference date / Calendar date.

Calendar date: _20/03/2012 05:59:36.522

Start: Other event reference

In the Reference event tree structure, check on the “Sun Pointing” end

“Sun Pointing” End

Role for reference: “Sun Pointing” end

Time delta: _0 days 00:00:00:000 hours

End: Angle

Angle: 10

Apply

Close

Now follow the similar step to set up the trajectory parameters for the arc #3. Change the title name to be Earth Pointing, use Periapsis and Apoapsis. Input the following parameters:

New General keplerian: Earth Pointing


Ellipse definition: <Periapsis & apoapsis>

Periapsis: 7371

Apoapsis: 9371



Inclination: 60

Argument of the periapsis:: 180

Anomaly: 0

Reference date: Calendar date

We usually keep the Reference date to be the same with START time. Therefore we can also get the Reference date from the START time. Now let’s put down the Calendar date for a while, and set up the START date first.


Start: Other event reference

In the Reference event tree structure, check on the “Sun to Earth” end

“Sun to Earth” End

Role for reference: “Sun to Earth” end

Time delta: _0 days 00:00:00:000 hours

Now switch the START option from Other event reference to Calendar date, copy the Calendar date and paste it to the Reference date / Calendar date.

Calendar date: _20/03/2012 06:02:31.492

Then switch the START option back to Other event reference, expand the Arcs in the tree structure, and check on the “Sun to Earth” end

Arcs (click the to expand)


End: Angle

Angle: 180

Apply

Close

Here we showed the two ways to get the Reference / Calendar date. As long as we keep the Reference date and START time the same, you can get the Calendar date by either way.

64

You can run the trajectory to see how the satellite moves along the orbit by clicking the triangle play icon (pointed by the red arrow in the above picture). Save the trajectory file. Please note: the Files of type should be .systri. File/Save as…


Save

5. Create a new Kinematics in Thermica v4 Click the Kinematics tab to switch to Thermica v4 Kinematics window.

Kinematics

Create a new Kinematics. Click File, and then pick the New.

File/New

The New Kinematics browser and 3D view graphics window show up. In the 3D view window, the red X, and white (later becomes blue) Y, Z are the three axes of the body coordinate system. It is the same as that in Patran and MSC Thermica v4 Modeler window. Double click the Kinematics. The New Kinematics edition form pops up.

Kinematics (double click)

In this example, we have 3 arcs with different kinematics laws. We will need to create 3 Phases for whole satellite during these 3 arcs. In the New Kinematics edition form, click Edit button at the top right side of the form.

Phases / Edit

The Kinematics phase edition form pops up. Right click the Default phase (default), select the Rename option.

Default phase (default) (right click) Rename

Change the Default phase (default) to be Sun Pointing. It will still be the default phase.

Enter the new phase name: Sun Pointing

OK

Apply & close_

Select the Sun option for the first Multiple laws – Sun Pointing:

Multiple laws: _Sun

SINDA for Patran Workshop 9 65 Let -Z coordinate direction of the model pointing to the Earth (the antenna points to the Earth):

Pointing vector:

X: 0

Y: 0

Z: -1

Input the Orbit planet reference north direction for the second Multiple laws:

Multiple laws: _Orbit planet reference north directionn

Let Y direction of the model points to the Earth north:

Pointing vector:

X: 0

Y: 1

Z: 0

Apply

Now create the second Phase for the arc #2. In the New Kinematics edition form, click Edit button at the top right side of the form. Phases / Edit Right click anywhere in the Kinematics phase edition form, select the Add option. Right click in the Kinematics phase edition form Add Input Sun to Earth for the new phase name.

Enter the new phase name: Sun to Earth

OK

Apply & close_

Keep the Sun option for the first Multiple laws – Sun to Earth:

Multiple laws: _Sun


Pointing vector:

X: 0

66

Y: 0

Z: -1

Input the Orbit planet reference north direction for the second Multiple laws:

Multiple laws: _Orbit planet reference north directionn

Let Y direction of the model points to the Earth north:

Pointing vector:

X: 0

Y: 1

Z: 0

Apply

Now create the third Phase for the arc #3. In the New Kinematics edition form, click Edit button at the top right side of the form. Phases / Edit Right click anywhere in the Kinematics phase edition form, select the Add option. Input Earth Pointing for the new phase name.

Enter the new phase name: Earth Pointing

OK

Apply & close_

Keep the Planet option for the first Multiple laws – Earth Pointing:

Multiple laws: _Planet


Pointing vector:

X: 0

Y: 0

Z: -1

Choose the pointed planets: _Earth

Input the Orbit Velocity vector for the second Multiple laws:


Multiple laws: _Orbit velocity vectorn

Let X direction of the model points to the orbital velocity direction:

Pointing vector:

X: 1

Y: 0

Z: 0

Apply

Switch the Phases to Sun Pointing (default), and then close the New Kinematics edition form.

Sun Pointing (default)

Close

Create a New Ball joint (3 dof) for the whole satellite maneuver based on the kinematics of the 3 phases. This is the second level kinematic for the whole satellite. If the satellite does not have the main body rotation, we do not need to create this kinematic. It is only useful for the second phase for the arc #2. Right click the main Kinematics, in the pull down menu, go to the following options. Kinematics (right click) Create kinematic body In Ball joint (3 dof) Switch the Phases to Sun to Earth.

Phases: Sun to Earth

Click the Add button after Kinematic Law – Sun to Earth, add a new 3 attitudes laws.

Kinematic Law – Sun to Earth Add

3 attitude laws

Modify the 3 attitudes laws as the follows. These rotations are only applied to the Sun to Earth phase. Please make sure the Phase elapsed time (sec) is selected. This is IMPORTANT too.

Axis Unit A1 A0

Z Phase elapsed time (sec) -0.42 0 Y Phase elapsed time (sec) 0.14 0 X Phase elapsed time (sec) -0.32 0

68

In this case, the Z, Y, X order is important, because the later rotation will be based on the previous rotation. In aerospace industry, usually we use Z, Y, X to represent Yaw, Pitch, and Row. Please follow this Z, Y, X order to input rotation angles and speeds. The New Kinematics edition form should look like the following figure:

Apply

Switch the Phases from Sun to Earth to Sun Pointing (default), then close the form.

Sun Pointing (default)

Close

Now follow the similar steps of problem 1 to define Kinematics for the solar panels. Right click the New Ball joint (3 dof), in the pull down menu, go to the following options. New Ball joint (3 dof) (right click) Create kinematic body In Pivot (1 dof)

SINDA for Patran Workshop 9 69 In New Kinematics edition form, check the very top data box, you should find the New Pivot (1 dof). This is the new Kinematic name, change it to solar_panels_py. (py as positive Y) New Pivot (1 dof) --- solar_panels_py The solar panels rotate around Y axis.

First rotation:

Axis: Y

You can either create the middle point or input values directly. Please reference the step 7 in Problem 1. Click Add button after the ORIGIN, then select One point translation.

ORIGIN Add

One point translation

Point 1:

X: 0

Y: 0

Z: 0

Transform 1:

X: 0

Y: 1.75

Z: 0

Click Add button at the right side of KINEMATIC LAW – Sun Pointing, then select Sun in the pull down menu.

KINEMATIC LAW – Sun Pointing Add_

Sun



X: 0

Y: 0

Z: -1

Apply

Switch the Phases from Sun Pointing (default) to Sun to Earth, Click Add button at the right side of KINEMATIC LAW – Sun to Earth, then select Sun in the pull down menu.

70

Sun Pointing (default) --- Sun to Earth

KINEMATIC LAW – Sun to Earth Add_

Sun



X: 0

Y: 0

Z: -1

Apply

Switch the Phases from Sun to Earth to Earth Pointing, Click Add button at the right side of KINEMATIC LAW – Earth Pointing, then select Sun in the pull down menu.

Sun to Earth --- Earth Pointing

KINEMATIC LAW – Earth Pointing Add_

Sun



X: 0

Y: 0

Z: -1

Apply

Close

We are now going to create another kinematic link for the solar panels on the –Y side with a kinematic name as solar_panels_ny (ny as negative Y). But this time instead of building it manually, we will copy the solar_panels_py and paste it under the New Ball Joint.

solar_panels_py (right click) Copy New Ball joint (3 dof) (right click) Paste solar_panels_py (1) (double click)

In the New Kinematics edition form, rename the name and modify the Y coordinate.

solar_panels_py (1) ---- solar_panels_ny


Transform 1:

X: 0

Y: -1.75

Z: 0

Apply

Close

Right click in the 3D View window and select Fit all option.

Right click mouse on 3D view Fit all

You can find four coordinate systems in the 3D view. The middle one actually contains two coordinate systems. They are for the whole satellite body. The other two are for the two solar panels respectively. Each frame here represents a kinematics law. The New Ball joint (3 dof) is under the main kinematics, adding some additional maneuvers at the second phase only. The two solar panels kinematics are under the New Ball joint (3 dof). The solar panels move with the body (obey the New Ball joint (3 dof)), and at the same time, trying best to point to the Sun.

You can right click on the 3D view window, select Test trajectory, select Custom trajectory, and then satellite2_1.systrj, and then select the phase in the Configuration window, you can view the kinematics animation. Please note: in Phase 1 and 2, the main body and solar panels have the same kinematics, therefore no relative movements (no solar panel rotation). In the Phase 3, the main body –Z points to the Earth, while the Solar panels –Z points to the Sun, therefore we can use animation to display the rotations only for the Phase 3.

72

At the lower left corner of the 3D view, click the Configuration View icon.

Configuration View

Change the phase to Earth Pointing.

Entities configuration Phase Earth Pointing

Close the Configuration View, and Remove the kinematic animation.

Close

Right click mouse on 3D view Test trajectory Custom trajectory satellite2_1.systrj Now you can view the solar panel frames rotation, also the velocity vector changes along with the ellipse arc #3. Please note: the animation time frame is for the whole orbit. So the Phase 3 kinematic is displayed over all the three arcs, only the second half of the animation is really for the Arc #3. You can see a small velocity vector changes in the Arc #3.

Right click mouse on 3D view Test trajectory Disabled

Save the Kinematic file. Please note: the Files of type should be .syskin.

SINDA for Patran Workshop 9 73 File/Save as…


Save

6. Modify the Mission in Thermica v4 Click the Mission tab to switch to Thermica v4 Mission window.

Mission

Translator automatically created a sysmis file as a default. You can edit this existing mission to meet your requirements.

Double click the Mission. In the Mission form,

Mission (Double click)

You can see the .sysmdl and .sysmsh files are referenced. We are going to add the newly created .systrj and .syskin files to this mission by clicking Add button, then <Select a file>.

Trajectory: satellite2_1.systrj

Kinematic Model: satellite2_1.syskin

TrueAnomalyStep: 10 __ ___

Please note: Under Variables, we can setup the Thermica variables: TrueAnomalySetup and TimeStep. Thermica may use either TrueAnomalySetup or TimeStep to setup the computation events (orbital intervals). It depends on which method is used. In our situation, we choose the anomaly step option in Step 2. So the TrueAnomalySetup variable is used here. The CompPtAtEnd variable is for the Eclipse and Penumbra points. If you want, you can modify the event computation method under the TimeLine by double click the Computation evenet rule(1). Please note: After editing under the Timeline tree structure, the Mission becomes inactive by some reasons. If you want to edit the Mission again, you may need to click one of the items in the Geometry tree structure, the Mission is active again.

Apply

Close

Assign the kinematic link to the antenna, the satellite2_1.sysmis edition form pops up.

Geometry / Mission / antenna antenna (double click)

In the satellite2_1.sysmis edition form, click Add after the KINEMATIC LINK, Check on New Ball joint (3 dof) to assign this kinematics to Mission. This will have the antenna perform extra rotation during the Phase 2, while in Phase 1 and 3, New Ball joint (3 dof) does nothing, except follows the main Kinematics.

74

KINEMAIC LINK Add_

New Ball joint (3 dof)

Apply

Close

Assign the Kinematic link to the body.

Geometry / Mission / body body (double click)

KINEMAIC LINK Add_

New Ball joint (3 dof)

Apply

Close

Assign the Kinematic link to the solar_panels_py.

Geometry / Mission / solar_panels_py solar_panels_py (double click)

KINEMATIC LINK Add_

solar_panel_py

Apply

Close

Assign the Kinematic link to the solar_panels_ny.

Geometry / Mission / solar_panels_ny solar_panels_ny (double click)

KINEMATIC LINK Add_

solar_panel_ny

Apply

Close

We need to create 3 Sequences to correspond the three Arcs. In the Timeline window, right click Sequences to create a new sequence. Timeline / Sequences Sequences (right click) Create sequence intervals Interval

SINDA for Patran Workshop 9 75 In the satellite2_1 edition form, make sure the Phase / Sun Pointing is selected.

Phase: Sun Pointing

START: Other event reference

In the Reference event tree structure, expand the Arcs.

Arcs (Click the to expand)

“Sun Pointing” start

Role for reference: “Sun Pointing” start

END: Other event reference



“Sun Pointing” End

Role for reference: “Sun Pointing” end

Apply

Close

Now let’s use another way to create second sequence for the arc #2. At the bottom of the

Thermica v4.5.3 GUI, find the vertical Timeline. At the Sequences row, you can find the just by the Sequences.

(Click on this icon)

Interval

The satellite2_1.sysmis edition form pops up, Make sure the Phase / Sun to Earth is selected.

Phase: Sun to Earth


In the Reference event tree structure, the “Sun Pointing(1)” end is automatically checked on. You can either use this one by default, or do the same thing as above to check on the “Sun to Earth” start. Here we just use the default.

“Sun Pointing(1)” End

Role for reference: *Sun Pointing(1)* end




76


Role for reference: *Sun to Earth* end

Apply

Close

You can use either way to create the third sequence for the arc #3.

Timeline / Sequences Sequences (right click) Create sequence intervals Interval

In the satellite2_1.sysmis edition form, make sure the Phase / Earth Pointing is selected.

Phase: Earth Pointing


“Sun to Earth(1)” End

Role for reference: *Sun to Earth(1)* end




“Earth Pointing” End

Role for reference: “Earth Pointing” end

Apply

Close

Click the in front of the Computation event rule (1), you will see the list of 37 computation

positions. Click the in front of the Computation event rule (2), you will see the 3 additional computation positions for the Penumbra and Eclipse. There should be one more position, but that position happens to be coincident with one of the 37 positions. Thermica v4 displays all the computation positions at the bottom of the Mission window.

Right click in the 3D View window, and then click Fit, and Trajectory,

Right click mouse on 3D View Fit Trajectory

SINDA for Patran Workshop 9 77 You should be able to see the model and orbit. At the lower left corner of the 3D view, click the Configuration View icon.

Configuration View

In the pop up 3D view configuration window, under Display, change the model scale to the Large model, check on Eclipse cones, and Trajectory arcs.

Display


Model scale: Large model

The Configuration view will be automatically closed.

Rotate the model so that you can see the model and the eclipse cone. You can run the mission by clicking the triangle play icon at the lower left corner of the 3D view window. You will see how the satellite moves along the 3 arcs. On the arc #1, both the main body and the solar panels point to the Sun. The solar panels do not rotate to the main body because they have the same kinematics. On the arc #2, the satellite main body rotates from Sun Pointing to the Earth Pointing. The solar panels rotate with the main body, and at the same time, the solar panels rotates so that the solar panels point to the Sun as much as possible. On the arc #3, the main body points to the Earth, while the solar panels point to the Sun. There arcs connect smoothly.

You can drag and move the in the Timeline / Views row, or use the animation to display the satellite movement and pointing.

You can monitor the Bata angle of the orbit, and the current True Anomaly of the solar panels which shows the deviation of the solar panels facing to the Sun. At the lower left corner of the 3D view, click the Configuration View icon,

78

Configuration View

In the pop up 3D view configuration window, under Entities configuration, change to Textual information tab; check on Beta Angle, and True Anomaly.

Entities configuration Textual information

Beta angle

True Anomaly

Close

At the upper right corner of the 3D View, you can find the textual information of Beta Angle and True Anomaly. You can add to display other parameters in real time if you want.

You can run the mission by clicking the triangle play icon at the lower left corner of the 3D view window. You will see how Beta angle and True Anomaly change with the orbit.

You can view the satellite and solar panels closely by using the Camera lock in Local orbital frame. This is the default frame, in case you want to change it back.

Right click mouse on 3D view Camera lock in Local Orbital frame

Adjust the 3D View to have a bigger view on the satellite and solar panels, and run the mission. Monitor the solar rotation and Sun shine on the satellite body. Please note: you may need to click the button to set the orbital back to the initial position.

SINDA for Patran Workshop 9 79 Save the mission file. Please note: the file is an existing file created by the translator. You do not need to use the Save as… option.

File/Save

7. Run radiation model in Thermica v4 Processing

Click Run icon (pointed by the red arrow in the above picture).

Run 4

Answer Yes for the pop up window to save the processing diagram

Yes

A Process run window pops up to show the running status. By default, the Mission, Radiation, Solar Flux, and Planet Fluxes options are checked. Click Run icon again.

80

Run

After running, you should see the “Result files have been loaded” at the end of the status messages. Check the running status. Make sure there are no errors messages, and then close it.

Close

You should see the result files are displayed in the Result zone in the Processing window.

8. Display radiation results in Thermica v4

SINDA for Patran Workshop 9 81 Click the Modeler tab to switch to Thermica v4 Modeler window.

Modeler Meshing

Configuration View

Click Entities configuration, make sure the satellite2_1.sysmsh is displayed. The results are based on the mesh. Under Shape Appearance tab, and click the following items.

Entities configuration Satellite2_1.sysmsh Shape Appearance

Result

satellite2_1


Mean Absorbed Solar Flux

Rotate and drag the model as shown below. The -Z side of the solar panels has more Absorbed Solar Flux. Please note: The translator creates two plate radiation surfaces for each single solar panel element. The +Z side does not receive any solar fluxes, and cannot see the other side.

Now check on satellite2_1.fp.h5.

satellite2_1_fp.h5

Earth Albedo Direct Flux

The -Z side of the satellite body and antenna has more Earth Albedo Direct Flux. Please note: This value is not a mean flux. It is changing along the orbit. You can run the animation to display the Earth Albedo Direct Flux.

82

You can also view the results in the Mission window. Please reference the Step 19 of problem 1. Rotate the model as shown below. You can run the animation to see the Direct Solar Flux vs orbital time.

9. Quit Thermica v4 and continue Sinda running MSC Thermica/Quit

SINDA for Patran Workshop 9 83 A pop up window asks if you really want to quit, answer Yes to confirm the quit.

Yes

Some popup windows ask if you want to save some files before closing, always answer No for not to save.

No

Sinda for Patran translator will continue to run. The translator will read the Thermica v4 results, along with SindaRad results and other FEM information to generate the Sinda input file. And then Sinda will continue to run. After Sinda has finished running, Patran output window will show Sinda “total run time” at the bottom.


Analysis


Verify the Job Name is satellite2.


Apply .

In the Patran message window, you should see “Result file Imported into Patran”.

12. Display the Steady State Result

Results

Action: Create

Object: Quick Plot

Select Result Cases: satellite2, steady state


Click on the Fringe Attributes icon and set up the Display option.

Fringe Attributes

Display: Element Edges

Click on the Reset Graphics icon and Wireframe icon.

Reset Graphics Wireframe

Apply

84

Rotate the model for a better view. Your model should look like the following figure:

13. Examine Input and Result files

Analysis


Edit/Manage Files...

Sinda Input File(.sin)

You can examine the input file and see how the Sinda for Patran translator creates the source data. The translator has automatically calculated the average heat flux based on the orbital heating data arrays which come from the radiation analysis (THERMICA). Close the satellite2.sin file after examination.

14. Perform the Transient State Analysis

Analysis

Action: Analyze





Apply


Transient State Setup

Choose Solution Routine: FWDBKL

You can calculate the orbital period = 6961 seconds in the previous Thermica V4 animation run. You can compare the start time and end time at the animation control pad. Here we will output 40 temperature results for the whole orbit, so the OUTPUT interval is 174.025 seconds.

TIMEND: 6961

OUTPUT: 174.025

OK

Specify Initial Conditions

Sinda Restart Option: Use Previous Results (if available)

OK


Check the current default radiation solver: SindaRad (Default).

SindaRad (Default)_

SindaRad Option Setup: Reuse Existing Results (if exist)

OK

OK


Check the Existing Customized Enclosures: 1, outside, active

Existing Customized Enclosures: 1, outside, active

Check the current selected radiation solver for this enclosure: THERMICA V4 (Selected).

THERMICA V4 (Selected)_

THERMICA Option Setup: Reuse Existing Results (if exist)

Orbital Option

Use the default Solar/Planetary Flux/RADK option.


86

OK

Modify

Close


OK

Output Routine Setup…

Thermal Studio Routines

Thermal Studio Routines: TSOUT_T-output temperature

OK

OK

Apply

Sinda for Patran will use the previous result as the initial temperature, and the existing radiation results will be used, therefore Thermica and SindaRad will not be called. You can rerun this model again and again for the dynamic thermal balance. You are not limited to make a transient run inside just one orbital period. In the transient analysis, the time dependent heat flux and time dependent radiation conductors will be used when there are moving parts in the model.


Analysis



Apply .

16. Display the Transient State Result

Results

Action: Create

Object: Quick Plot

Select Result Cases: satellite2, Time=6.961000E+03nrf


Apply


The last result case of your model should look like the following figure: If you want to create an animation display, please reference Workshop 1 for more details.

17. Plot temperature curves in Thermal Studio

Analysis

Action: Thermal Studio


Apply

Right click the Result.0 icon. In the pop up window, click New Plot and input a new plot name.

Result.0 (right click) New Plot

Name: -Y_Solar_Panel

OK

In the Output Data list box, drag the slide bar down and double click the 396 ---T396, 414---T414, 432---T432, and 450---T450 lines. These nodes are the middle nodes of the four -Y solar panels. These four results will be added into the Plot Data list box. Click OK to plot the curves.

OK

88

The beginning of the curves shows the effect of the initial temperatures from the steady state run. Close Thermal Studio by either click the X or File/Exit. To complete this exercise, close the database and quit Patran.

File/Quit…

*************************************************************************************************** Congratulations! You have successfully completed Workshop 9 of Sinda for Patran. If you have any comments or questions, please do not hesitate to contact us.

workshop9 msc satellite in orbit

Documents