Autodesk Simulation Mechanical and Multiphysics

[#1]

Greetings,

1. I've been trying to do a shrink fit between a simple cylindrical hub and a round shaft (using ASM).

2. I've been using solid brick elements for both parts.

3. I draw the parts assembled in inventor with 0.15 mm radial interference

4. I import into ASM

5. I mesh with 8 node bricks

6. I change bonded contact to shrink fit/no sliding

7. I enter radial interference as 0.15 mm

8. I solve with either sparse solver or automatic

9. I get the message 'not tied down properly'

10. The solution will not finish

I've spent quite a while on this.  Could someone please give some suggestions on shrink fits?  I've used Inventor for this without a problem!

[#2]

Did you apply any boundary condition / constraint to your model?

Looks like that’s what you are missing for your setup

Best Regards

Sualp Ozel, PE

Product Manager

Digital Simulation
Autodesk, Inc.

[#3]

Hi and thanks for replying.

Yes, I've used a BC.  I've tried all sorts on fact.

Since I posted this, I'm getting a result but not a correct one. 

-Hub is a simple Hollow cylinder, OD = 216mm, ID = 139.85 mm with 135 mm axial length

-Shaft is solid and is 140 OD by 300 long with keyway

-Static Linear Stress Analysis

Contact Settings:

-0.075mm radial interference

-friction set to 0.25

-Surface contact direction = normal to first part/surface

-Direction Tolerance Angle = 10

-Shrink Fit / Sliding

Analysis Parameters:

-sparse solver

-iteration - mixed

-200 iterations

-stabilization Global/initial

-stiffness reduction attempts 2

Mesh on Both Parts

-4 mm tets, 2nd order Or 6mm bricks

Results Hub

Radial Stress at ID = -550 N/mm^2 (should be -62 N/mm^2)

Radial Stress at Od =0 (Ok)

Axial Stress at ID = 1550 N/mm^2 (should be 152 N/mm^2)

Results Shaft

Radial Stress at Od = -650 N/mm^2 (Should be -62 N/mm^2)

Axial Stress at ID = -350 N/mm^2 (should be -62 N/mm^2)

The results are close to 10 x too high.

Your thoughts

[#4]

I created the same setup using Inventor and ASIM-Mech 2013. the only difference in my design was the contact type. I used Shrink fit without sliding so that the model becomes stable. also using this contact type i was able to compare the results i get from Asim-Mech to Inventor-Sim. I am attaching my results images. You will see that with this setup the results for both software are very similar. I will also try to attach the Inventor part/assembly files along with the ASIIM-Mech Archive file to this post. Hope this helps

Sualp

[#5]

Sualp,

thanks for this.  Could you please send the ach file.  I'm mainly interested in the radial contact pressure

Regards

[#6]

Due to its size, I cannot seem to attach the archive to the forum. If you can e-mail me your contact information, I will be happy to send it to you directly. -Sualp sualp.ozel@autodesk.com