Creo simulate difference between solid and beam calculation

[BartL]

Hi All,

I have a fairly simple question I hope, but for some reason can't figure it out myself.

When I run a simulate analyses on the shaft below I'm reading much higher stress results than what I calculate by hand. But when I run the same analyses on a beam section the results are lower than the hand calculation. For this reason I'm not feeling very confident on the results at the moment.

The situation is as followed:

The shaft has fixed displacement contraints on the pink surfaces with all rotational movements "free" and also axial movement free. On both outer ends I have placed a planar contraint to make it "fully contraint".

The load is a radial bearing load on the green section. The situation can be compared to the fin of a bow-shackle. 

Below the results of this analysis.

And this is the beam analysis:

And the results.

What am I missing here?

Thanks in advance for the help!

[skunks]

This problem is not simple at all 😂
No result is correct:
- Analytical calculation and the beam model are not applicable
- The 3D model has singularities and is also incorrect

[BartL]

For what reason is the beam model not applicable? In my opinion this is exactly where it should be a strong tool.

And what is the best practice to solve a simple calculation like this?

[skunks]

--> Bearing stiffness is decisive; this is a highly nonlinear problem.

[BartL]

That helps!

However te second question remains. What would be the best way to solve a simple calculation like this?

[skunks]

🤔 attached is a presentation on the topic (unfortunately in German)

if necessary, you can translate it using Google...

[BartL]

Thanks, I can read German 😉

However this is way to complex for a (what should be) a simple calculation to check the manual values.

[skunks]

--> anbei ein vereinfachtes Modell.

Lagersteifigkeiten sind willkürlich gesetzt.

[BartL]

Unfortunately I don't have an advanced licence so I can't use your file. I'm only using the standard simulate coming with a creo design essentials license. 

[skunks]

You use Creo Simulation Elite 😁

Simulate Elite 

[skunks]

for Elite

[skunks]

for Advanced

[BartL]

This works! And seems to give me a more accurate result!

Now I'm curious how do you define the right spring properties for different load cases? I've never used much springs idealizations before so there is a bit of learning curve left for me here.😉

[skunks]

I model real bearings for contact analysis 😁

[BartL]

I know but for future use I would like to know how to get realistic spring properties. You have defined some values there, how did you get them or is it simple experiece?

[skunks]

yes,  it's simple experience 😂

intuition...

[ilyachaban]

Also one small inconsistency. 
3D model has axial displacement locked from both sides
1D model has axial displacement locked only from right side (according to the image)

[BartL]

No, the 3D model wasn't locked axial but has planar constraints on both end. It has a 100% symmetrical setup. Why it is reading different results on both ends is a big question for me as well.