Stress Analysis on a Wheel

[Anonymous]

I am a Teacher for a High School Design Drawing and Productions class, and am going to integrate a module to an existing lesson plan. The concept would be to have the students take 2 of there already 5 made wheels/rims and put them in the stress analysis feature of Inventor. I want them to be able to set it up as real to life as possible and based on my research it should be as followed...

Problem: Setting up the parabola to span the 80° within the parametric design of Inventor.

Here is my current setup: Please inform me if you think it would be better to have it different.

Material: Aluminum 6061 (probably could be different but this is the least of my worries at this time)

Contraint:

Loads: Based on the first posted image it is a pressure that is interacting between the centerhub and the 80° span to the bottom. I don't know how to get this span so I have this...

Results:

The wheel shifts and rotates because it is not constrained to a plane. In most cases when its attached to a hub/car it would camber out but testing it alone, would have the focus on the connections (spokes) from the center out to the beads of a rim is my understanding.

Video Results:
http://www.youtube.com/watch?v=aX8B784G_3w
http://www.youtube.com/watch?v=53AWiXKTDu4

http://www.youtube.com/watch?v=vmUUd0bs5aM

I want my results to have the outter rim to be stable, much like like in this video
http://www.youtube.com/watch?v=gWgIVypPFjs

Even though the following  is posted by an engineer, I don't think it is tested like it is in industry
http://www.youtube.com/watch?v=OGINdCcUn9A

[JDMather]

Attach your ipt file here.

Are you familiar with Split face?

[Anonymous]

The ipt file is too large to be attached to the forums. Here is the link to the ipt

I'll mark it as Accept as Solution once I know your method gives me the results I'm looking for...

[JDMather]

You should indicate when you are not using the latest version of the software.
Students can download Inventor 2012 for free from http://www.autodesk.com/edcommunity

The part can be attached here by

1. Rolling up the End of Part Marker and save in a rolled up state.
2. Right click on the filename and select Send to Compressed (zipped) Folder.

[JDMather · Accepted solution]

See the V-shaped sketch I used to Split the faces.
If you want to distribute the load per your first post you will have to do multiple splits.

Note that 6000 psi is not 6000 lbf.

Inventor returns a total area of 2*(3.912in^2) surface area.
If I apply a full 296psi (not tapered as in the first post) I calculate total 2316 lbf which sounds about right (if I reduce by tapering off as sugggested in the first post).

[JDMather]

Also, your first post says stress analysis - but the analysis type is set to Modal in the file you attached here?

[henderh]

I'm not sure if this helps, but the Bearing Load automatically applies a parabolic load distribution.

  As JD already alluded to, you'd have to convert pressure to force if using Bearing Load.

Thanks, -Hugh

(ps: I noticed there is no relief to mount the tire in the Inventor model image)

[Anonymous]

But the parabolic load is supposed to be distributed in just that 80 degree span...

So I would have to take the 296 psi, determine that exact surface area on that bead and take a percentage because I don't want it going all the way around the bead?

No relief, are you talking about a center hole for the hub that would exist dead center? If so, thanks, brain fart.

is the only way to do the 80° span by doing split to faces sketch in Inventor 2012 because I'm almost certain its not in 2011

[JDMather · Accepted solution]

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@Anonymous wrote:

....because I'm almost certain its not in 2011

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Been there for as long as I can remember.  (My memory isn't all that good anymore - but it was in 2011).

[henderh]

JD is right, we've always had to split the face to add a "localized" load.

<<So I would have to take the 296 psi, determine that exact surface area on that bead and take a percentage because I don't want it going all the way around the bead?>>

I don't think you'd need to take a percentage since pressure is already on a per unit basis.

Pressure load is evenly distributed, acting normal to the face at all points.  Contrary to the image, we cannot have a pressure load acting only in the vertical direction since it is applied to a cylindrical face.  The load direction will be radial instead.  So there are two things pressure cannot do here, act only vertically and with a parabolic load distribution.

Bearing load can do these two things.

Here's what I'm thinking you can do:

1)   Split the face to 80 degrees as JD has shown

2)   Add the pressure load, fixed constraint to the lug holes, and solve.

3)   View the reaction force of the fixed constraint (RMB on the fixed constraint in the browser).  Note the vertical component value (it should be the same as the overall magnitude)

4)  Delete the pressure load and add a Bearing load in the vertical direction using the reaction force value.

5)  Re-solve

Now this will provide a parabolic load distribution acting only vertically to the cylindrical face.  The load magnitide should also be correct since it was derived from the pressure value.

What I meant by the relief to mount the tire is that if you look at the side view image of the loading diagram, you'll see that there is a large conical face.  In the Inventor model, it is a cylindrical face.  Unless there is some relief there, you won't be able to mount a tire since the tire bead will not be able to stretch over the rim bead without the relief.  The tire needs to mount at a large enough angle to the rim to slip the tire bead over.  I didn't even notice the missing hub hole.

Hope this helps...

Best regards, -Hugh

[Anonymous]

JD Mather and Hugh, thank you so much...this totally does it, I am not fond with the stress analysis environment and never used split before. You two rock!

[JDMather]

Search Amazon.com on author Wasim Younis for an Inventor book on this topic.

[Anonymous]

Just got back from Thanksgiving vacation and tried what you posted earlier but got stuck....

3)  View the reaction force of the fixed constraint (RMB on the fixed constraint in the browser).  Note the vertical component value (it should be the same as the overall magnitude)

Under load : Pressure 1 : Total Displacement

Y Displacement:

Why are they different when you said they should be the same?

4)  Delete the pressure load and add a Bearing load in the vertical direction using the reaction force value.

5)  Re-solve

Is it possible you include a video or more step by step instructions for steps 3 & 4?

[Anonymous]

And as you can see with the wireframe, it still shifts and twists when lookin at in the profile view

[Anonymous]

Alternative Solution to my problem easily explained...can't believe i didn't see this in my research

http://sustainabilityworkshop.autodesk.com/tutorial/formula-sae-wheel-baseline-simulation 

[g199301gg]

Hi JD Mather..

I study mechanical engineering and I am trying to do stress analysis on a BMW M5 wheel I made...
Can you give me more information about what i must do so my stress analysis is correct ? I tried to understand all you guys said on this forum but I cant understand how to do it on my inventor file...I have Inventor 2014 proffesional...can you give me a piece of advice or step by step what i must do ?? 

Thanks  a lot

[JDMather]

Start a new thread and attach your *.ipt file.

[Anonymous]

Please download and follow step by step MS Word attached files. I used this as a High School DDP Assignment. The only things that you may want to change is the Design Objective: Static, Material and other variables. Please be aware that stress analysis is very specific and entails very speicfic constraints and details in order to achieve accurate results. These results are only as accurate the input data and reasoning given from the user. Hope this helps. I also have other attachments if the one below does not suffice.

Step By Step Instructions

Examples from Students in the past are attached.

[g199301gg]

Thank you very much for the fast correspondence, I appreciate it a lot...
I will try to do the same thing to my project and I will inform you as soon as possible !
This the wheel i am trying to analize.... I hope you like it, its the first thing i have ever made...