Inventor's Dynamic Simulation Tutorial question

[Anonymous]

Hi all,

If you do the dynamic simulation - Part 2 in Inventor's tutorial, one of the sections is ''Exporting to FEA'' (screen print shown below). It says that you can do that with each component you want to analyze in FEA. I tried doing this on the 'Bevel Gear' or 'Cam Lobe' but an error regarding flexible part appears, why is this?. I followed the tutorial and everything works as expected, also the 'follower' FEA works fine.

Also I would assume that you can export the Cam Lobe into FEA to see how it handles the resultant forces or not?

Thanks

[jalger]

Hi Nac69,

You need to make sure it has degrees of Freedom (DOF) Availble to move. ( in this case you need to flag the assembly as "Flexible").

If you right click on the sub assambly and select "Flexible" it should move. (and it will work for dynamic simulation).

Dynamic simulation only works on parts with at least 1 DOF.

If you have the part grounded, or fully constrained (0 DOF) then it will only work with a Static Analysis.

I hope this helps,

James

[Anonymous]

hi jalger,

Thanks for your reply. I opened the Cam Crank subassembly and unground the cam lobe. The I made the subassembly 'Cam crank' flexible and tried again but another error appeared (shown below), I don't know what could be wrong. I understand how it should have at least 1 DoF but I thought it did because it is rotating about its axis and therefore this would count as 1 DoF wouldn't it?

I can't attach the file because it's too big.

thanks

[TheCADWhisperer]

That tutorial is garbage - should be an embarrassment to Autodesk.

[jalger]

Hmmm...

The Tutorial file was anhcored (and Built) in such a way that you can't Export data for everything.

In this case the issue is the welded Group, I suspect their are other issues that would prevent this as well. (If its Welded its not supposed to move)

If you had a Contact set you would need to Temporarily disable it as well (since the CAM Would be Calculated in the Dyanmic Sim Environment instead).

TheCADWhisper meationed:

"That tutorial is garbage - should be an embarrassment to Autodesk"

Yeah its not the best example in the world. (Its not even the Best example in their Tutorial Set!)

(They used to have a robot arm in the tutorial set that worked better for it then the cam example, Even the Wiper blades example was better)

I hope this helps,

James

[TheCADWhisperer]

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@jalger wrote:

..... Even the Wiper blades example was better)

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The wiper blades example is garbage.  I can allow for the wiper blades to not follow the windshield, but one of the mechanism parts crashes right through the glass.  That is inexcusable in my opinion.

[Anonymous]

Hi jalger,

the reason I am asking about this is because I have a similar problem with my project and thought that the tutorial might help me out. 

I have the following system:

I wanted to do DS so that I can design part #2 because I thought that it would take into account account the weight of the shaft attached to the gear as well as the torsion from the shaft rotating, etc.

When I set everything up I can only look at the forces involved with base 3 (and therefore apply FEA on part 3) , but I am interested in the gear primarily (part 2). I can't export the gear into FEA because there is no joint involved apparently, I cannot set this joint appropriately to do so and I don't know how to do this. Parts 1,2 are connected by fasteners then these two-part 'assembly' slides into a base shaft in part 3 (female-male connection type).

I think maybe I am not dealing with the fasteners correctly but I have no clue, maybe inventor just doesn't work like that?? In that case I would just try to approach this problem by using static analysis on the gear and using torques,forces computed in the DS, like manually exporting it to FEA, using values from the output grapher in the DS environment.

Any suggestions, ideas? I have no idea how to deal with all this because I've been teaching myself DS without any proper training or reference textbook.

Thanks