nas120 ws10 fairing

8/10/2019 NAS120 WS10 Fairing

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NAS120, Workshop 11, May 2006

Copyright 2005 MSC.Software Corporation

WORKSHOP 11

SPACECRAFT FAIRING


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Workshop Objectives Learn to use Groups and Lists


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Problem Description In this exercise, a spacecraft fairing will be constructed. Curves and

surfaces will be used to define the fairing geometry. The finiteelement model will consist of 2-dimensional elements with 1-dimensional elements applied at various edges of the geometry. The

1-dimensional elements will represent stiffeners for the structure.


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Suggested Exercise Steps

1. Create a new database called fairing.db and set the model preferences.2. Create the model geometry.

3. Create the mesh seeds for the model.

4. IsoMesh the model using Quad4 topology.

5. Check the free edges, equivalence the model, and then check the freeedges again.

6. Create a new group called FEM that contains only the finite elemental

model. Then post only the FEM group.

7. Create two material properties, alum_1 and alum_2.

8. Create two fields, one for temperature and the other for thickness.

9. Create element properties.

10. Create a temperature boundary condition.

11. Create a series of lists containing elements that satisfy these following

requirements: 1) the elements are made up of the alum_1 material, 2) theelements are greater than 0.98 in thickness, and 3) the elements have a

temperature greater than 230.0 degrees.

12. Intersect lists a and b to produce a list of elements that satisfy the first two

conditions.


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Suggested Exercise Steps (Cont.)

13. Create another list that satisfies the third condition.14. Intersect the new list with the other list to produce a group of elements that

satisfy all three conditions. Then, place these elements in a separate

group.

15. Post the group containing the elements produced in step 14.

16. Create 2 new groups, each containing elements with different property sets.

17. Change the display attributes for each group.

18. Post each group separately, then post both groups together.


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Step 1. Create New Database

Create a new database and set the model

preferences.

a. File: New.

b. Enter fairing for the File Name.

c. Click OK.

d. Set the Tolerance to Default.

e. Make sure that theAnalysis Code

andAnalysis Type are set to

MSC.Nastran and Structural,

respectively.

f. Click OK.

a

b c

d

e

f


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Step 2. Create Model Geometry

Create the points and curves that

represent the outline of the fairing.

a. Geometry: Create / Point / XYZ.

b. Enter [30 0 0] under PointCoordinates List and clickApply.

c. Geometry: Create / Curve / XYZ.

d. Enter and [50 40 0]

under Vector Coordinates List and

Origin Coordinates List,

respectively.e. ClickApply.

f. Click on Cycle Show Labels icon.

g. Click on Point Size icon to increase

the point size.

h. Geometry : Create / Curve / Point.

i. Click on Point 1 under Starting

Point List and click on Point 2 for

Ending Point List.

a

b

c

d

e

h

i

j

f g

S 2 C M d l G (C )


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Step 2. Create Model Geometry (Cont.)

Illustrated here are curves thatrepresent the basic geometry for the

fairing. These curves will be revolved

360 in order to get the final model.

St 2 C t M d l G t (C t )


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Create the fairing by revolving

curves 1 and 2 about the fairings

vertical center line.

a. Geometry: Create /

Surface / Revolve.

b. Enter Coord 0.2 for Axisc. Enter 360 for the Total

Angle.

d. Click on Curve List.

e. Click on Curve 1, then click

on Curve 2.

f. Viewing: Angles.

g. Enter 30 0 0 under Angles.

h. ClickApply.

a

b

c

d

e

f

g

St 2 C t M d l G t (C t )


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Change the display

preferences in order to get a

clearer visual of the model.

a. Display: Geometryb. Enter 3 for Number of

Display Lines

c. ClickApply, then

Cancel.

a

b

c

Step 3 Create Mesh Seeds


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Step 3. Create Mesh Seeds

Create a finite element mesh so

that 4 node Quad elements are

created every 10 along the

circumferential edges.

a. Elements: Create / Mesh

Seed / Uniform.

b. Select Number of

Elements and enter 36

for the Number.

c. Click on Curve List.

d. Select the top

circumferential edge of

the fairing (Surface 1.3).

a

b

c

d

Step 3 Create Mesh Seeds (Cont )


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Step 3. Create Mesh Seeds (Cont.)

In the vertical direction (y-direction),

define a smoothly transitioning mesh

density. The elements along the top of

the cylinder are 2.5 times as large as

those along the bottom edge (taperedend) of the fairing.

a. Elements : Create / Mesh Seed /

One Way Bias.

b. Select L1 and L2 and enter 7 and

10 for L1 and L2, respectively.

c. Click on Curve List and selectCurve 1.

d. Elements : Create / Mesh Seed /

One Way Bias.

e. Select L1 and L2 and enter 4 and

7 for L1 and L2, respectively.

f. Click on Curve List and selectCurve 2.

a

c

b

d

e

f

Step 4 Create a Mesh for the Model


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Step 4. Create a Mesh for the Model

Now that the mesh seeds have

been created, mesh the model

using Quad4 topology.

a. Elements: Create / Mesh /

Surface.

b. Select Quad, IsoMesh,

and Quad4.

c. Rectangular pick the

entire model and click

Apply.

d. Remove the display lines

by clicking the on the

Display lines icon.

e. Remove the labels by

clicking the Cycle Show

labels icon.

f. Decrease the point-sizeby clicking on the Point

Size icon.

a

b

c

e df

c

Step 4 Create a Mesh for the Model (Cont )


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Step 4. Create a Mesh for the Model (Cont.)

Mesh the horizontal

(circumferential) edges of each

surface with two-noded bar

elements.a. Click on Plot/Erase icon.

b. Click on Erase under

FEM.

c. Click OK.

d. Elements: Create / Mesh

/ Curve.

e. Set Topology to Bar2

f. Shift select the 3 curves

(as indicated).

g. ClickApply. c

d

e

f

g

a

f b

Step 5 Observe the Free Edges


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Step 5. Observe the Free Edges

Check the free edges of the

model, equivalence, and then

check the free edges again.

a. Click on the Plot/EraseIcon.

b. Under FEM, click Plot.

c. Elements : Verify /

Element / Boundaries.

d. Select Free Edges

under Display Type.

e. ClickApply.

f. Elements :

Equivalence / All /

Tolerance Cube.

g. ClickApply.

h. Repeat steps c

through e.

c

d

e

f

g

a

b

Step 6 Create a New Group


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Step 6. Create a New Group

Replot the FEM and create a

group called FEM containingonly the finite element model.

Post only this new group to the

viewport.

a. Group: Create

b. Enter FEM for the New

Group Name.

c. Select Unpost All Other

Groups.

d. Change Group Contents

toAdd All FEM.

e. ClickApply.

a

b

c

d

e

Step 7 Create Material Properties


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Step 7. Create Material Properties

Create the first material for the

model. Material alum_1 will be

applied to the top(cylindrical)

portion of the fairing.

a. Materials: Create /

Isotropic / Manual Input.

b. Enter alum_1 for the

Material Name.

c. Click on Input

Properties.

d. Select Linear Elastic and

enter 1.05E7, 0.33, and

2.6E-4, for Elastic

Modulus, Poisson Ratio,

and Density, respectively.

e. Click OK.f. ClickApply.

d

e

a

b

c

f

Step 7. Create Material Properties (Cont.)


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Step 7. Create Material Properties (Cont.)

Create the second material for

the model. Material alum_2 will

be applied to the bottom

(tapered) portion of the fairing.

a. Materials: Create /

Isotropic / Manual Input.

b. Enter alum_2 for the

Material Name.

c. Click on Input

Properties.d. Select Linear Elastic and

enter 1.18E7, 0.33, and

2.4E-4, for Elastic

Modulus, Poisson Ratio,

and Density, respectively.

e. Click OK.

f. ClickApply.

d

e

a

b

c

f

Step 8. Create Fields


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p

Define a field that represents the

varying thickness.

a. Fields: Create / Spatial /

PCL Function.

b. Enter thickness for the

Field Name.

c. Enter 1.5-Y/160 for the

Scalar Function and click

Apply.

a

b

c



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Plot the function defined in

the field.

a. Field: Show

b. Select thickness as

the field to show.

c. Click Specify Range.

d. Enter 160.0 for the

maximum and 20 for

the number of points.

e. Click OK.

f. ClickApply.

d

e

a

b

c

f



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Delete the plot.

a. XY Plot: Delete /

XYWindow

b. Select XY ResultWindow.

c. ClickApply.

d. Choose Yes to delete

the result window.

a

b

c

d



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Define a field that represents the

varying temperature distribution.

a. Fields: Create / Spatial / PCL

Function.

b. Enter temperature for the

Field Name.

c. Enter 200.0-(150.0/160.0)*X

for the Scalar Function and

clickApply.

a

b

c



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Plot the function defined in

the field.

a. Field: Show

b. Select temperature

as the field to show.

c. Click Specify

Range.

d. Enter 50.0 for the

maximum and 10 forthe number of

points.

e. Click OK.

f. ClickApply.

bd

e

c

a

f

Step 9. Create Element Properties


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Create two element properties

which include the material

definitions and varying thickness.

a. Properties: Create / 2D /Shell.

b. Enter prop_1 for the

Property Set Name.

c. Click on Input Properties.

d. Click on the Select Material

icon.e. Select alum_1 from the

Select Material list box.

f. Click on the Front view

icon.

f

d

e

a

b

c

Step 9. Create Element Properties (Cont.)


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Finish creating the first property set.

a. Set the thickness type to

Element Nodal and click on the

Select Field icon.

b. Select thickness as the Scalar

Spatial Field.

c. Click OK.

d. Click on Select Members and

click on the Shell Element icon.

e. Select the top(cylindrical) portionof the fairing by dragging a box

around the desired section (as

indicated on next page).

f. ClickAdd , thenApply.

a

d

b

c

d

f

f



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Illustrated here is the desired

application region for the first

property set.



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Create the second property set.

a. Properties: Create / 2D / Shell.

b. Enter prop_2 for the Property

Set Name.c. Click on Input Properties

d. Click on the Select Material

Icon.

e. Select alum_2 from the

Existing Materials.

f. Click on the Select Field Icong. Select thickness from the

Existing Fields box.

h. Click OK.

i. Click on Select Members and

select the bottom (tapered)

portion of the fairing bydragging a box around it(as

indicated on next page).

j. ClickAdd, thenApply

d

f

eg

h

a

b

c

i

j



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Shown here are the

elements for the

desired application

region of the second

property set.

Step 10. Create Temperature Boundary Conditions


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Define the models varying temperature

distribution.

a. Loads/BCs: Create /

Temperature / Nodal.

b. Enter temp for the New SetName.

c. Click on Input Data.

d. Click on Temperature and

select temperature from the

Spatial Fields.

e. Click OK.f. Click on Select Application

Region.

g. Under Geometry Filter, select

FEM.

h. Click onAppl icat ion Region

and select the entire model.

i. ClickAdd, then, OK

j. ClickApply.

d

e

g

h

i

a

b

c

f

j

Step 10. Create Temperature Boundary Conditions (Cont.)


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Turn off the temperature labels

in order to get a better

visualization of the model.

a. Display: Load/BC/Elem.

Prop

b. Under Loads/BCs

remove check under

Temperature.

c. ClickApply, then

Cancel.

a

b

c

Step 11. Create Lists


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Use Lists and groups to filter thengroup the quad elements that have thefollowing

attributes:

Material : alum_1

Thickness : > 0.98

Temperature : >230.0

a. Tools : List / Create

b. FEM / Element / Attribute

c. UnderAt tr ibute, selectMaterial.

d. Under Existing Materials,select alum_1.

e. Set the Target List to A andclickApply.

a

b

c

d

e

The contents of List Acompose of elements that

satisfy the first condition;

they are made up of the

alum_1 material.

Step 11. Create Lists (Cont.)


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Define List B to include only the

Quad elements that have a

thickness greater than 0.98.

a. Properties: Show.

b. Under Existing

Properties, select

Thickness.

c. Set Display Method to

Scalar Plot.

d. Select Current

Viewport, select FEM

and clickApply.

a

b

c

d

Shown above is a fringe plot the model by thickness. Those

elements that are thicker than 0.98 will be included in the next

list.

Step 11. Create Lists (Cont.)


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After defining the list parameters,

add the elements greater than 0.98

in thickness to list B.

a. Tools: List / Create

b. FEM / Element / Attribute.

c. UnderAttribute, select

Fringe Value.

d. Under Fringe Tools, select

default_Fringe.

e. Change the inequality to >

and enter 0.98.

f. Select B for the Target

List.

g. Click onApply.

a

The contents of List B

include all elementsthicker than 0.98.

b

c

d

e

f

g

Step 12. Intersect Lists


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Intersect Lists A and B and

replace the contents of List A

with the elements found in the

intersection.a. Tools: List / Boolean

b. Click on the Intersect

icon.

c. Click on Replace A.

The new List A is

composed of elementsthat satisfy both

requirements: they are

made up of alum

a

b

c

Step 13. Create More Lists


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Perform a final classification of the

elements. Isolate those elements

that satisfy the third condition of the

applied temperature load > 230.0.

a. Loads/BCs: Plot Contours /Temperature.

b. Select temp from the

Existing Sets.

c. Select Temperature under

Select Data Variable.

d. Select the FEM group andclickApply.

a

b

c

d

Step 13. Create More Lists (Cont.)


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Clear the contents of List B and add thevalues obtained from the final classification.

a. Tools: List / Create.

b. FEM / Element / Attribute.

c. Select Fringe Value and

default_Fringe for Attribute and Fringe

Tools respectively.

d. Change the inequality to > and enter

230.0.

e. Select B for the Target List.

f. Click on Clear on the List B form

g. ClickApply on the List Create form.

a

b

c

d

e

f

g

Step 14. Intersect Lists Again


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Lists A and B will be intersected

again to create a List C. This list

will contain the elements that

satisfy all three conditions. Thecontents of List C will then be

placed into a new group called

common_quads .

a. Tools: List / Boolean

b. Click Clear.

c. Click on the Intersecticon (It may be necessary

to click on any of the

other icons first).

d. Click onAdd To

Group

e. Enter common_quadsfor the Group Name.

f. ClickApply, then Cancel.

a

b

c

d e

f

Step 15. Post Group


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Post the common_quad

group. This is the group of

elements that satisfy allthree of the conditions

defined earlier.

a. Group: Post

b. Select the

common_quads

group under SelectGroups to Post.

c. ClickApply, then

Cancel.

d. Click on the Iso 1

view icon.

a

b

c

d


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Step 16. Create Two New Groups


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Create two new groups, prop1_group

and prop2_group .Then, change the

display attributes for each group.

a. Click on the Reset Graphics icon.

b. Group: Create

c. Create / Property Set.

d. Enter prop1_group for the Group

Name.

e. Select prop_1 under Property

Sets.

f. ClickApply.

g. Repeat steps b through f entering

prop2_group for the Group Name

and selecting prop_2 under

Property Sets.

a

b

c

d

e

f

g

Step 17. Change the Display Attributes


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Set the entity coloring and labeling to Group mode andthen change the display attributes for each of the two

new groups.

a. Display: Entity / Color / Label / Render

b. Select Group under Entity Color and Labeling.

c. Select the prop1_group under the Target

Group(s).d. Select HiddenLine for the Render Style and

select dark blue for the Shade Color.

e. ClickApply.

f. Select the prop2_group for the Target

Group(s).

g. Select Wireframe for the Render Style andselect red for the Shade Color.

h. ClickApply, then, Cancel.

a

b

c

d

e

f

g

h

Step 18. Post Groups


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Change views and post the

prop1_group.a. Click on the Iso 3 view

icon.

b. Group : Post

c. Under Select Groups to

Post, select prop1_group .

d. ClickApply.

a

b

c

d

Step 18. Post Groups (Cont.)


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Post only the prop2_group.

a. Group: Post

b. Under Select Groups to

Post, selectprop2_group .

c. ClickApply.

a

b

c

Step 18. Post Groups (Cont.)


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Post both the prop1_group

and the prop2_group.

a. Group: Post

b. Under Select Groups

to Post, select both

prop1_group and

prop2_group .

c. ClickApply.

a

b

c


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nas120 ws10 fairing

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