Solid modeling

WORKSHOP 7

PARASOLID SOLID EXAMPLE

PAT301, Workshop 7, May 2002 WS7-1

WS7-2PAT301, Workshop 7, May 2002


� Problem Description� Create a parasolid solid model of a tension fitting. This is done

using some of the parasolid tools in MSC.Patran, e.g. boolean. Create a tet10 solid element mesh model, including the needed load and constraint, material and element properties, and analysis input. Run the finite element analysis using MSC.Nastran. Then, display the deformation and stress results in Patran.


� Suggested Exercise Steps1. Create a new database for the tension fitting model.

2. Create all the necessary 2D Geometry.

3. Extrude the surface to begin creating the solid model.

4. Create a solid shell by removing part of the solid.

5. Create fillets for all inside edges of the solid.

6. Create holes for the model by creating solid cylinders that pass through it,

and then use boolean to subtract the cylinders.

7. Create cylinders to imprint the model.

8. Imprint the solid using the cylinders.

9. Delete the cylinders used for imprinting.

10. TetMesh the completed solid

11. Create loads and constraints on the model that will be used in the analysis.

12. Create material properties for the model.

13. Create the 3D element properties.

14. Check to see that the load case Default has the load and constraint.

15. Run the analysis by sending the model to MSC.Nastran.

16. Access the results by attaching the XDB file.

17. Post-process the results from MSC Nastran.


Step 1. Create New Database for Tension Fitting

Create a new database called

tension_fitting.db.

a. File / New.

b. Enter tension_fitting as the

file name.

c. Click OK.

a

b c


Step 2. Create Surface

Create the Geometry for the tension

fitting.

a. Geometry : Create / Surface /

XYZ.

b. Enter <5 2 0>for Vector

Coordinates List.

c. Enter [0 0 0] for Origin

Coordinates List.

d. Click Apply.

a

b

c

d


Step 2. Create Surface (Cont.)

Copy points at opposite corners.

a. Click increase Point Size icon

to show all points enlarged.

b. Geometry : Transform / Point /

Translate.

c. Enter <0.5 0 0> for

Translation Vector.

d. Select top-left corner and click

Apply.

e. Enter <0 0.5 0> for

Translation Vector.

f. Select bottom-right corner and

click Apply.

a

b

c

d

e

f

d

f



Create a curve by connecting the

two translated points and break the

surface with the curve.

a. Geometry : Create / Curve /

Point.

b. Click on one of the two

points from translation as the

starting point and the other

as the ending point.

c. Click Apply.

a

b

c

b



Break the surface and delete the

upper portion of the original

surface.

a. Geometry : Edit / Surface /

Break.

b. Select the rectangular

surface for the Surface

List and the sloped curve

for the Break Curve List.

c. Click Apply and Yes when

message box appears.

d. Click the Refresh

Graphics icon.

a

b

c

d



Delete the upper surface

(above the break curve).

a. Geometry : Delete /

Surface.

b. Click on the triangular

surface for the

Surface List.

c. Click Apply.

a

b

c


Create a parasolid solid

by extruding the surface

in the z-direction.

a. Geometry : Create

/ Solid / Extrude.

b. Make sure

TetMeshable solid

icon is selected.

c. Enter <0 0 2> for

the Translation

Vector.

d. Click Apply.

e. Click Iso1 view.

f. Click the Smooth-

shaded icon.

Step 3. Extrude the Surface to Create Solid

a

b

c

d

ef


Step 4. Create a solid shell

Edit the solid using the shell

method to create a shelled

solid.

a. Geometry : Edit /

Solid / Shell

b. Enter 0.25 for

Thickness. Turn off Auto Execute.

c. Click on Solid Face

List and hold down

the shift button and

select the top, sloped,

and front faces of the

solid.

d. Click Apply.

a

b

d

c

c


Step 5. Create Fillets

Create the fillets on the inner

edges of the solid.

a. Geometry : Edit / Solid /

Edge Blend.

b. Make sure that the constant

radius icon is selected.

c. Enter 0.25 for Constant

Radius.

d. Make sure Edges of Solid

icon is selected.

e. Click on Solid Edge List

and use the shift-click

technique and select the 3

edges on the inside of the

solid.

f. Click Apply.It may be necessary to

rotate the object in order

to see then inner edges

more easily. This can

be done by holding the

middle mouse button

and moving the mouse.

a

b

c

d

f

e

e


Step 6. Create Holes for the Tension Fitting

Create the holes for the tension

fitting by creating primitive solids

that pass through the solid, then

subtracting them.

a. Geometry : Create / Solid /

Primitive.

b. Select the cylinder icon

c. Enter 2.0 for the Height and

0.25 for the radius.

d. Enter [-1 1.25 1] for the Base

Center Point List and Coord

0.1 for the Axis List.

e. Click Apply.

f. Geometry : Edit / Solid /

Boolean.

g. Select Subtract icon.

h. Select the tension fitting for

the Target Solid.

i. Select the cylinder for the

Subtracting Solid List.

j. Click Apply.

a

b

c

d

e

f

g

h

i

j


Step 6. Create Holes for the Tension Fitting (Cont.)

Create the points where the three

bottom holes will be placed by

translating an existing point and,

then translating again.

a. Click wireframe icon.

b. Geometry : Transform /

Point / Translate.

c. Enter <0 0 -0.5> for

Translation Vector.

d. Select point at base edge

of fillet and click Apply.

e. Enter <-0.75 0 0> for

Translation Vector.

f. Select translated point and

click Apply.

g. Enter <-1.50 0 0> for

Translation Vector.

h. Enter 2 for repeat count.

i. Select translated point and

click Apply.

a

b

c

d

f

h

i

d


Step 6. Create Holes for the Tension Fitting (Cont.)

Create cylinders using points as base

centers and then create holes by

subtracting them from the solid.

a. Click Smooth shaded icon.

b. Geometry : Create / Solid /

Primitive.

c. Select cylinder icon.

d. Enter -1.0 for Height List

and 0.125 for Radius List.

e. Use the shift-click technique to

select the three translated

points for Base Center Point

List.

f. Enter Coord 0.2 for axis list

and click Apply.

g. Geometry : Edit / Solid /

Boolean.

h. Select subtract icon

i. Select tension fitting as Target

Solid.

j. Shift-click all three cylinders for

Subtracting Solid List.

k. Click Apply.

It may be

necessary to rotate

the object several

times in order to

select the cylinders

with ease

b

c

d

e

f

g

hi

j

k

j

a


Step 7. Create Cylinders to Imprint Tension Fitting

Create a point in the center of the big

hole in order to create the cylinder to

imprint onto the solid. Then create

all four cylinders that will be used for

Imprinting.


b. Geometry : Create / Point /

ArcCenter.

c. Select the larger hole edge.

d. Geometry : Create / Solid /

Primitive.

e. Select cylinder icon

f. Enter 1.0 for Height and

0.371 for Radius.

g. Click on point in the center of

the big hole.

h. Enter Coord 0.1 for Axis List.

i. Click Apply.

j. Select Smooth Shaded icon.

a

b c d

e

f

g

hi

j

c g


Step 7. Create Cylinders to Imprint Tension Fitting (Cont.)

Now, create the three cylinders

that will be used to imprint the

base of the tension fitting.


b. Geometry : Create / Solid /

Primitive.

c. Select cylinder icon

d. Enter 0.5 for Height and

0.298 for Radius.

e. Shift-click on point in the

center of each of the base

holes.

f. Enter Coord 0.2 for Axis

List.

g. Click Apply.

h. Select Smooth Shaded

icon.

a

b

c

d

e

fg

h


Step 8. Imprint the Solid

Use the cylinders to imprint the

solid and then delete the

cylinders, resulting in the

finished solid.

a. Geometry : Edit / Solid /

Imprint.

b. Shift-click all four

cylinders under

Imprinting Solid List.

c. Select the tension fitting

for the Imprinted Solid

List.

d. Click Apply.

The solid may

seem unchanged,

but the imprints on

the solid will not be

visible until the all

the cylinders have

been deleted.

a

b

c

d


Step 9. Delete the Cylinders

Delete the cylinders and make sure

imprint method was completed.

a. Geometry : Delete / Solid

b. Shift-click all four cylinders

for Solid List.

c. Click Apply.

The imprints created

from the previous step

are now visible.

Imprinting is used to

show where washers

on an object will be

placed. It allows for

application of a total

load over the

imprinted area, which

will be performed later

a

b

c


Step 10. TetMesh the Completed Solid

Create the TetMesh for the

tension fitting.

a. Elements : Create /

Mesh / Solid.

b. Make sure Tet,

TetMesh, and Tet10

are all selected.

c. Click on Input List and

select all solid.

d. Remove check for

Automatic Calculation

and enter 0.25 for

Global Edge Length.

e. Click Apply.

a

b

c

d

e


Step 11. Create Loads and Constraints

Create the loads and constraints for

the model.

a. Click Smooth Shaded icon

b. Loads/BCs : Create / Total

Load / Element Uniform.

c. Enter Force as the New Set

Name.

d. Click Input Data…

e. Enter <-5000 0 0> for the

Load and click OK.

f. Click Select Application

Region…

g. Select the vertical solid face

created by imprinting at the

larger hole, then click Add.

h. Click OK

i. Click Apply.

a

b

c

d

e

f

g

h

i

Illustrated here is the

desired application

region.

g


Step 11. Create Loads and Constraints (Cont.)



Create the constraints on the base holes.

a. Loads/BCs : Create /

Displacement / Nodal.

b. Enter Fixed as New Set Name.

c. Click Input Data…

d. Enter <0 0 0> for Translation

only, and click OK.

e. Click Select Application Region.

f. Click on Select Geometry Entities.

g. Select Surface or Face icon

h. Shift-click the surface(inside) of the

three holes on the base, and

Click Add.

i. Click OK.

j. Click Apply.

a

b

c

d

e

f

g

h

i

jh

Illustrated here is the

desired application

region for one of the

three holes.




Step 12. Create Material Properties

Create the material properties for the

model.

a. Materials : Create / Isotropic /

Manual Input

b. Enter Aluminum for Material

Name.

c. Click Input Properties…

d. Enter 10E6 for Elastic

Modulus and 0.3 for the

Poisson Ratio.

e. Click OK

f. Click Apply.

a

b

d

c

e

f


Step 13. Create 3D Element Properties

Create the 3D element properties for

the tension fitting.

a. Properties : Create / 3D /

Solid.

b. Enter 3D_tets for Property

Set Name.

c. Click Input Properties…

d. Select Aluminum from

Material Property Sets for

Material Name.

e. Click OK

f. For Application Region,

select entire solid by dragging

a box around it and click Add.

g. Click Apply.

a

b

c d

ef

g


Step 14. Check the Load Case

Check the load case Default to make

sure that the load and constraint are

selected.

a. Load Cases : Modify

b. Click on the load case name

Default.

c. Check to see that both the

load and constraints are

assigned.

d. Click Cancel.

a

b

c

d


Step 15. Run the Analysis

Run the Analysis with MSC.Nastran.

a. Analysis : Analyze / Entire

Model / Full Run.

b. Click Translation

Parameters...

c. Make sure XDB and Print is

selected.

d. Click OK.

e. Click Solution Type…

f. Make sure LINEAR STATIC

is selected.

g. Click OK.

h. Click Apply.

a

b

c

d

e

f

g

h


Step 16. Access the Results

Attach the XDB file and access the

results.

a. Analysis : Attach XDB / Result

Entities / Local.

b. Click Select Results File…

c. Select tension_fitting.xdb

and click OK.

d. Click Apply.

a

b

c

d


Step 17. Display Results

Create a deformation plot

a. Results : Create /

Deformation.

b. Select Displacements,

Transitional from

Select Deformation

Result.

c. Click Apply.

a

b

c


Step 17. Display Results (Cont.)

Erase the geometry and do not show

the undeformed model, so that

only the deformed model is shown.

a. Display : Plot/Erase…

b. Click Erase under Geometry.

c. Click OK.

d. Click Display Attributes.

e. Remove check from Show

Undeformed.

f. For the Render Style, choose

Shaded.

g. Click Apply.

a

b

c

d

e

g

f


Step 17. Display Results (Cont.)

Here is the deformation

plot without the

undeformed plot and

geometry. It is often

more convenient to

observe the deformation

without the original

shape in order to get a

better view of the model.


Step 17. Read Results (Cont.)

Plot the von Mises

stress for the model.

a. Results : Create /

Fringe.

b. Select Stress

Tensor from

Select Fringe

Result.

c. Select Display

Attributes, then set

Display to Element

Edges

d. Click Apply.

It may also be helpful to change

the view several times in order to

get a better visualization of the

deformations. This can be done

either by holding down the middle

button on the mouse, or using the

view icons.

a

b

c

d

Date post:	16-Jul-2015
Category:	Education
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