topic Re: Settings for FEA Simulation in Inventor Forum

Settings for FEA Simulation

BeKirra — Tue, 13 Jul 2021 01:44:34 GMT

I have a sugar storage tank and need to perform FEA simulation.

At this time I only performed creating mesh view.

However it took more than a day and the simulation seems not going to the end.

Your help(s) are much appreciated.

The screenshot (below) shows the mesh setting.

Please note:

1. For simplifying the analysis all life loads are not considered.

2. Fixed constraints on foot (4 off)

Here is the tank details (simplified model)

Capacity: 60,000Kg (Sugar)

Tanks Size (approx.): Ø4000mm x 10000mm (height)

Tank wall thickness: 4mm (typical)

Footing: 20mm Thick (typical)

Material: Stainless Steel 304

Re: Settings for FEA Simulation

JDMather — Tue, 13 Jul 2021 03:17:15 GMT

Attach your file(s) here.

You have an extreme aspect ratio - you should be using Thin Feature shell elements.

Sugar would exert forces more like liquid - you will need to use a hybrid technique that resembles hydrostatic forces in Inventor (or use Nastran).

Re: Settings for FEA Simulation

BeKirra — Tue, 13 Jul 2021 03:52:30 GMT

Thanks for your reply.

Please find the file.

Note: I use 2019 version.

Re: Settings for FEA Simulation

JDMather — Tue, 13 Jul 2021 13:11:51 GMT

Go through this first - then post back if you still have questions...

Re: Settings for FEA Simulation

johnsonshiue — Tue, 13 Jul 2021 21:41:48 GMT

Hi! Another approach to consider is to create a part simulating the sugar (dead weight). You can compare the results to see which one is more realistic.

Many thanks!

Re: Settings for FEA Simulation

BeKirra — Wed, 14 Jul 2021 06:58:36 GMT

Thanks to @JDMather I will have a look your video.

And also thanks to @johnsonshiue Do you mean to create a sugar solid in the model?

Re: Settings for FEA Simulation

johnsonshiue — Wed, 14 Jul 2021 19:19:08 GMT

Hi! Yes, I think you could simulate the sugar as a solid body. It may not be accurate but no FEA can depict precise deformation. It is just how close the result will be.

Many thanks!

Re: Settings for FEA Simulation

JDMather — Wed, 14 Jul 2021 20:09:39 GMT

@johnsonshiue wrote:

I think you could simulate the sugar as a solid body.

I don't think that would work.

How would this body impart load onto the tank?

Only force would be load due to gravity.

I still think my hybrid technique (if staying in Inventor) of treating the sugar as sort of a fluid exerting graduated pressure on the sides of the tank as well as the bottom is the way to go.

Only for calculations to convert load to pressure I would model the sugar as a solid body gradually increasing height in reverse from top to bottom getting weight to convert to pressure (will require some hand calcs, at least for the bottom). Sugar would have more friction than fluid so pressure on sides of tank would be a bit less than the calculation, but as you said this would be an approximation anyhow.

See anything wrong with my thinking?

@BeKirra

Have you made any progress?

Re: Settings for FEA Simulation

BeKirra — Thu, 15 Jul 2021 23:44:02 GMT

Thanks @JDMather your video helps a lot. I am still working on my model and am learning from your tips.

Another questions here.

1. How to take the weight of tank to the FEA when it is big enough?

2. If it is the case, will you insert "force" or "pressure" to the feet?

Thanks.

Re: Settings for FEA Simulation

JDMather — Fri, 16 Jul 2021 10:52:24 GMT

1. The weight of the tank (not including sugar) is based on the material and Gravity.

2. Fixed constraints bottom of the feet and turn on Gravity. Inventor will figure out the rest.

Re: Settings for FEA Simulation

swalton — Fri, 16 Jul 2021 16:27:40 GMT

Over the last 18 months or so, I've had to learn much more than I wanted to about bulk material bins and hoppers.

You might find these references useful to guide the loading of the FEA.

https://www.aiche.org/sites/default/files/cep/20131125_1.pdf

https://www.qualicer.org/recopilatorio/ponencias/pdfs/0013041e.pdf

https://www.hindawi.com/journals/ace/2018/3673515/

https://news.bulk-online.com/bulk-solids-handling-archive/bulk-materials-storage-design-considerations-for-the-design-of-materials-handling-storage-plants.html

Re: Settings for FEA Simulation

BeKirra — Sun, 18 Jul 2021 23:51:19 GMT

Thanks @JDMather

How to place gravity to a model? I take your video as an example.

It seems Inventor only allows to place gravity on a single point.

How to place it to a 4 foot tank? Or did I miss something?

And also thanks to @swalton I will take some time to read through the articles.

Re: Settings for FEA Simulation

JDMather — Mon, 19 Jul 2021 11:20:49 GMT

Gravity effect the entire environment - you only need to set the direction.

Click the bottom face of the tank to set Gravity perpendicular to the face or select any vertical edge to set the direction.

If you have not applied Gravity before - I assume that you are a beginner with FEA.

I urge you to use extreme caution in interpreting the results in any analysis you run.

Re: Settings for FEA Simulation

BeKirra — Mon, 19 Jul 2021 11:46:37 GMT

@JDMather wrote:
...
Click the bottom face of the tank to set Gravity perpendicular to the face or select any vertical edge to set the direction.

Yes, I am not familiar with FEA.

How to place gravity to the model that is shown on my 1st post?

on the bottom cone?

Thanks.

Re: Settings for FEA Simulation

JDMather — Mon, 19 Jul 2021 11:54:17 GMT

Gravity is everywhere - ignore the location of the arrow glyph, only the direction of the arrow is important.

You could select the bottom of the cone or the bottom of a foot or any vertical edge of a foot, or....

If you would like the arrow in the center for aesthetic purposes, simply expand the dialog box and select Use Vector Components.

Re: Settings for FEA Simulation

BeKirra — Mon, 19 Jul 2021 12:04:39 GMT

Thanks again. @JDMather 👍

BTW I misplaced a post in other forum.

https://forums.autodesk.com/t5/simulation-mechanical-forum/fea-files/td-p/10478122

Can you please take a look? The question is about securing FEA files.

Thanks.