Can't run stress analysis

[Anonymous]

I have a college project for which I need to run a stress analysis. I am trying to run the analysis on an assembly. However, it is not running. It is not even giving me any errors, the green bar just gets so far across and then dissapears - no error messages or anything to indicate that it was even attempting the analysis.

I am new to Inventor but I enjoy using it. However, this issue has got me completely stumped. Please help! I have tried to attach the relevant files; assembly file and zipped part files..

Many thanks

[JDMather]

I do not see any Contacts defined between your parts?

This should have been covered in class.

What book are you using to learn Inventor FEA?

Have you gone through the Tutorials?

Have you installed all Service Packs and Updates for your version of Inventor?

[JDMather]

I am not sure what it is - but there seems to be something very strange with your geometry.  This might be a good one for Autodesk to examine.

[Anonymous]

Thanks for replying 🙂

I'm not using any book nor following any tutorials. I should say this is Uni rather than college, and we are receiving very little in terms of structured teaching - the class is a mix of novice to expert users. We ask Qs as and when and receive 1-on-1 help. As far as I am aware I have everything that I need to be able to run a stress analysis - I am running the student version of 2014 at home and what appears to me to be the same at college.

I am not sure I understand what is meant by defining contacts - all I have figured out so far is that by ticking the "contact set" option on each part and activating the solver, the parts will behave as if there is physically something there, i.e. they are not able to pass through each other.

I guess that clicking the automatic button should generate something under contacts, and I assume the same happens to you as me and the green bar gets so far and then appears to crash?

Might this have something to do with the issue - each of those snap-fit "lugs" that you can see is a clearance fit and I have constrained them to their respective holes by their center axes, i.e. they do not physically "touch" each other.

[JDMather]

iProperties indicates that you are running 2014 SP0

There are several Service Packs and Updates available for r2014.

Assembly Contact Sets have nothing to do with FEA Contacts.

You can set a Contact Tolerance in the  (gap distance) in the Simulation Properties.

There is something wrong with your Adaptor Frame.

I could not establish Contacts with that part.

If I create a new assembly and assemble a couple of the other parts - the do work.

I recommend that you go through the Tutorials so that you understand how FEA Contacts should work.

[Anonymous]

Thanks again, you've given me a couple of directions to go in so I'll check them both out. Are the tutorials you talk of built in to the program or on the net somewhere?

Will the tutorials give me an idea of what a successful "contact" should look like, so that I know when I've cracked it?

[JDMather]

I did some more checking and found an error with this face (and the cooresponding face on the other side).

You will never get this assembly to work without first fixing this part.  (since it is a Derived Component - I could not track down the exact problem without the original file).

[JDMather]

Assembly FEA Tutorial

Important page

[Anonymous]

Interesting - the "clamp" part should sit flat under the frame there but clearly can't because of the the way I have filleted that lug onto the frame. I thought nothing of it and had it 3D printed as is and accepted that small "blemish". Perhaps, though, the fact the clamp cant sit as intended is causing issues?

EDIT - In fact from a quick glance at your first screenshot I can see that some interference between the clamp part and the lug fillet must be occurring. Surely that is the route of the problem!

[Anonymous]

I read the tutorials and they were very useful. I have changed the design of the frame and clamp in order to avoid the overlap that we identified. I still can't generate contacts though 😞 I have attached the redesigned clamp and frame parts.

You also mention the fact that the frame is a "derived" part - I guess this relates to theway that I modelled the lugs, which I created as an individual part and then added onto all the parts where they were needed, inc the frame. I have attached all the files that I used along the way to creating the frame part, as-is in the adaptor assembly file.

Appreciate your continued help!