Simulation Deformation Results being WEIRD

[Anonymous]

Please refer to the three pictures to know what I am talking about.

When I run a FEA on this part, my stresses are normal, I have double checked all my force, pressure, torque, and constraint inputs, AND their units. All things seem normal.

SO when I run the simulation, I get these weird results. When I change the view settings to Actual, it looks like a teradactyl in flight... and then when i put adjusted x1, things are normal again... 

The plot I am in is 5000 psi max and it is a steel sheet part. As you can see there is no concern of deformation according to these numbers since mild steel is around 40 ksi yield.

Somebody please help me resolve this ever so vexing dilemma so my client does not think I am a complete chump!

Thanks!!!!!!! 

[JDMather]

You didn't state what version of Inventor, including Service Packs.

You didn't state if you use Thin Features analysis on that part (assembly?).

You didn't state or show what the (calculated) actual deformation actually is.

[Anonymous]

Version: 2015 Professional

Thin feature: No, doesnt work well for me when trying to simulate hydrostatic forces (i was told in the last forum that I bitched about Inventor to that there is no other way to simulate hydrostatic than to section faces into different layers and apply different gradient pressures... fun I know), so just cranked the mesh size down.

Actual Deformation: No idea, This is a hopper that is subjected to hydrostatic forces from product placed inside, plus 300 ft lb of torque from an electric motor, plus a few thousand pounds of reaction forces on the two edges edges from where a hydraulic lifting mechanism pivots on, plus self weight, plus thrust force from the bearing mounted in the screw conveyor.

The model is telling me its around 500 inches of displacement.............................................................................................. 

[JDMather]

---

@Anonymous wrote:

.... 

The model is telling me its around 500 inches of displacement.............................................................................................. 

---

Inventor analysis is limited to relatively small displacements.

Obviously your analysis is not set up correctly - or the analysis set-up violates one or more of the limitations of the solver (which the person setting up the analysis should understand at the outset).

Attach your file here an eliminate all doubt.

[Anonymous]

I think we figured it out. Our pressures were too high is all. I just found it weird that the actual displacement was so out to lunch but the "adjusted x1" showed it being LESS deformed than in reality... I am sure there is a reason but I do not know it.

Another question: When I apply a force to multiple bodies, and I enter a value for magnitude, is the force a TOTAL value or is it PER FACE? Solidworks had a button to specify which one you wanted and it also showed you beside the force glyph what the value computes to. I do not see anything of that nature in Inventor. Thanks in advance for clarifying, I could not find a straight forward answer online which is weird because it strikes me as a common question.

Thanks guys, one day I will get this Inventor stuff figured out and stop bitching about it 🙂

[JDMather · Accepted solution]

I have my students create a simple little example - both ways, to answer this question.

They seem to remember better when they have actually done the "experiment".

(In other words - I don't remember, I do a little experiment and observe for logical results.)

[jacektylenda]

Hello,

I have also noticed such behaviour before (in SolidWorks Simulation). This is just a matter of displacement magnitude (which one can set to better see and analyze the displacement results).

I made some interesting graphics several years ago in SW Sim in which one can set the magnitude manually. Setting it to hundreds or thousands gives some interesting results. And your "teradactyl" is also nice. I have my collection here: https://www.facebook.com/femartmovement/photos/

Regards.