Jump to content

FEA crash with a spoked wheel


Lor

Recommended Posts

Hi to All

 

I'm new to Inventor and to this helpfull forum:)

 

In these days i designed an spoked wheel (iron made), because i want to know what is its max stress and safety factor.

 

But i don't know why each time i run FEA, there is an error that stop the analysis...

 

inv4.jpg

 

Some one can help me?

 

I'm using Inventor 2008 (i know...is old..)

Edited by Lor
Link to comment
Share on other sites

  • Replies 23
  • Created
  • Last Reply

Top Posters In This Topic

  • Lor

    12

  • shift1313

    6

  • rdharvey

    4

  • JD Mather

    1

Top Posters In This Topic

Posted Images

the error is telling you what your problem is... either your dimensions are invalid or there are features that are too small to compute compared to the rest of the geometry. find out what they are and just suppress them in your model.. is there hanging geometry because the part doesnt look overly complex and it should be able to mesh it easy enough.

Link to comment
Share on other sites

There aren't small features. The FEA work only when i supress circular pattern and mirror...and seems there isn't small angled part outside the solid.

 

To design all the rods i deleted some features but i don't think that this influences the FEA...or not?

Link to comment
Share on other sites

(spam filter :reallymad:)

 

The part file is 270 kb so i can't upload here...

Try to open the link at the bottom of my first post.

THen click on "quì" and must begin the download.

 

Thanx a lot for your help!

Link to comment
Share on other sites

These errors happen when you are trying to mesh a part with possibly some small fillets or really small features. You will need to simplify the model. For instance the "bead" area on your rim has a very small sunken area that looks to have small fillets. If you made your "rim" flat the analysis would probably look the same as what you have there, only it would not cause any issues.

 

And so you know the output you get from FEA is only as good as your input. If you setup your conditions or loads wrong, the output you get will not tell you anything. I can tell you right now looking at your load arrow the output will probably not be very useful.

 

What kind of condition are you trying to simulate? a braking force? Wheel hitting a pot hole? Side loading? What kind of loads are you working with and what are your fixed conditions?

Link to comment
Share on other sites

New final version (correct but still doesn't run FEA)

 

PullyOk.zip

 

:cry:

 

P.S. I see now your message, shift1313, i'll try to do so!

 

My force is apllied to all the external surface, and simulate a tension of a steel rope around the whell.

The problem isn't this beacause if i delete all rods less one, the FEA runs ok...

Edited by Lor
Link to comment
Share on other sites

It could be the fact that the rod is so much smaller than the other solids in the model. You may need to do some mesh adjustments to make some fine mesh in the intersection between the spokes and the rim. I cant open your file up here because i dont have IV08 or newer at work so hopefully someone else can shed some light on it.

Link to comment
Share on other sites

i have had a quick look. and surely your force was the wrong way? surely the force will inward rather than outward?

 

You need to know what you want out of an fea study before you just jump into it, its not that simple. set up is crucial.

 

study worked fine here with your force direction the way i believe it should be... i have a stress report that i have produced.

 

i also think the way you have modeled it is over the top. there is no need for all the sweeps.

Link to comment
Share on other sites

Before you continue with FEA I recommend that you read this document.

http://home.pct.edu/~jmather/AU2006/MA13-3%20Mather.pdf

You sketches are not constrained.

Never (well almost never) use zero dimensions.

You used Sweep for a Revolved feature.

You use Sweep for an Extruded feature.

Extra workplanes that aren't needed.

Link to comment
Share on other sites

First, thanx to all!

 

The force doesn't matter. The fea crash during the finite element mesh building. The costrain is on the internal tube. The same force/constrain work if there is only one rods.

I'm not able to explain in english, but i know the reactions, forces, materials and the other characters of my real whell. I want to know the safety factor and stress.

 

No one extra workplane is used to design, but just the minium requied to draw the first 2 rods at 22,5 deg angle. Inv. 2008 hasn't the same commands as 2011 that makes you able to rotate the revolve or mirror features.

Thankyou JD Mather for your manual, i'll read as soon as i can!

 

The problems begin if i add more than one rod....

 

(sorry i work all days with a biggest sectorial forum powered by vBulletin , but this have big problems concerns the upload and the spam filter.)

asino.jpg

Link to comment
Share on other sites

change your model. The rim should be a revolve. and the are two work planes doing nothing. simulation worked fine oin my system i don't think you know what you want out of the study therefore your setup is not correct.

Link to comment
Share on other sites

Sorry Tiger for my errors!

 

change your model. The rim should be a revolve. and the are two work planes doing nothing. simulation worked fine oin my system i don't think you know what you want out of the study therefore your setup is not correct.

 

I have just redesign all and revolved the rim. Same error. Workplanes are necessary to design the second rod. Trust me, there isn't way to do it in inv08 whitout 2 workplanes (one for the circle e the second for the axis where to sweep).

 

So if in your system work, can u post an image of stress analysis or safetyfactor? I'm tired of doing this...

Link to comment
Share on other sites

Lor, i have inventor 07 at work, ill try to reproduce the rim when i get a chance to see if i get errors with the spokes. How many spokes are on the rim?

 

Also in a real spoked rim the spokes are attached with nipples that will allow the spokes to bend and deflect. having them rigid in your model wont produce the same results as with them "floating" to a certain extent.

Link to comment
Share on other sites

There are 16 rods inclined...model is complex.

 

I didn't want to invent any stuff! This is the reproduction of my real whell in my

garage, that i want to test.

 

 

100_9363 (Small).JPG

Link to comment
Share on other sites

As i suppose the problem is Inventor 2008.....

 

The same whell (same part file!!!!) open with Inventor 2011 gives all ok:

 

vonmi.jpg

 

That's all folks.

Thanks to all :-)

Link to comment
Share on other sites

Works fine in inventor 11(2007)

 

I drew this one so i suppose its an issue with the model and not actually performing the operation. I just went off the picture and no dimensions. The hub here is 3" diameter and the overall wheel was 36" i think.

 

If i get time i will open your file tonight and see if i can find a problem. Is it possible there is a small gap between the end of your spoke and the rim? If you used a sweep and your sweep path didnt start and end inside the solid body of the rim or hub this could be your problem. Mine was created by extruding and using the To Next option for the end condtion to ensure a proper fit between spoke and rim.

SpokedWheel.jpg

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...