Inventor General Discussion

Inventor General Discussion

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Contributor ing
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ing
Posts: 12
Registered: ‎09-02-2011
Message 1 of 46 (992 Views)
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FEA 64 bit problem

992 Views, 45 Replies
11-15-2013 07:54 AM

We have recently switch from XP to win7. Basically 32 to 64 bit. The simulation results in the 32bit vertion of inventor has always been second to none. But the new (new to us) 64 bit vertion has yeiled some false results. more worriingly the results indicate that the model is in fact good enough to do the job. I have attached a document outlining my findings.

 

I have contacted my software supplier and they reported it to autodesk. Autodesk has in turn said that the problem is noted but the case has been closed.  I have no problem accepting a minor deviation, even 5% but the results can have an error of 0% to 80%.

 

If anyone knows a cure or has had this type of trouble, please let me know.

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cwhetten
Posts: 1,071
Registered: ‎09-03-2008
Message 2 of 46 (966 Views)

Re: FEA 64 bit problem

11-15-2013 09:30 AM in reply to: ing

Thank you for posting your analysis.  The results are very disturbing.  We will have to exercise extreme caution when using the simulation module.

 

Cameron Whetten
Inventor 2014

Contributor ing
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ing
Posts: 12
Registered: ‎09-02-2011
Message 3 of 46 (935 Views)

Re: FEA 64 bit problem

11-15-2013 02:11 PM in reply to: cwhetten

I have conducted more comparison simulations on inventor 2014 64 bit and inventor 2012 32 bit. here are some screenshots of my simulations. 

 

Inventor 2012 von mis:

Stress inv2012.jpg

Inventor 2014 von mis:

Stress inv2014.jpg

 

The expected stress at this location is 37 Ksi. This stress value was calculated via the traditional method. This means that the new inventor is wrong by 36%!!! The simulations are identical. it is the same model, same material and the same forces and constrains. It is bizzare that I am the first to report this problem. if you are have a simmilar issure please post it on this thread. I will be adding some more examples later on.

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blair
Posts: 4,034
Registered: ‎11-13-2006
Message 4 of 46 (925 Views)

Re: FEA 64 bit problem

11-15-2013 02:43 PM in reply to: ing

Unbelievable!

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IV2015 up2 PDSU / Sim Mech 2015 /
Win7-64
EVGA X79 - Classified, iCore7 3930k 32Gb Quad-Channel
950Gb (2 x 500Gb Sata III SSD RAID0 Adaptec 6805E Controller)
Nvidia GTX-690 Classified - 335.23
SpacePilot Pro 3.17.7, 6.17., 4.11
Contributor ing
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ing
Posts: 12
Registered: ‎09-02-2011
Message 5 of 46 (888 Views)

Re: FEA 64 bit problem

11-17-2013 06:29 PM in reply to: blair

I have done some more analysis comparisons. Below is an analysis performed in Inventor 2012:

Inventor 2012 7083 beam stress.jpg

 

And here is the exact same analysis on Inventor 2014:

Inventor 2014 7083 beam STRESS.jpg

Contributor ing
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ing
Posts: 12
Registered: ‎09-02-2011
Message 6 of 46 (886 Views)

Re: FEA 64 bit problem

11-17-2013 06:35 PM in reply to: ing

Even small analysis are yeilding false results!!! This one is 3x3 square tubing with some plates on it.

Inventor 2012:

Inventor 2012 WO28438 STRESS.jpg

and now Inventor 2014:

Inventor 2014 WO28438 Stress.jpg

 

From 30.44 Ksi to 17.43 for the exact same analysis, almost half. anyone else has this problem!?

Contributor ing
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ing
Posts: 12
Registered: ‎09-02-2011
Message 7 of 46 (877 Views)

Re: FEA 64 bit problem

11-17-2013 06:52 PM in reply to: ing

If there were any doubts this one will clear them up! This is the worst one to date.

Inventor 2012:

Inventor 2012 WO27522 STRESS.jpg

 

Inventor 2014:

Inventor 2014 WO27522 STRESS.jpg

The 2012 vertion gave us a max of 88.77ksi. The 2014 vertion gave us 0.12ksi...... with the EXACT same model. I simply ran the simulation in 2012 and then re-ran it in 2014. Thats an error of 99.8%. Please autosesk... make a patch for the analysis enviroment. The worst part is that Inventor used to school Solid Works in the analysis department.

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blair
Posts: 4,034
Registered: ‎11-13-2006
Message 8 of 46 (872 Views)

Re: FEA 64 bit problem

11-17-2013 06:58 PM in reply to: cwhetten
I thought we could elevate this to Support for them to look at it.
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IV2015 up2 PDSU / Sim Mech 2015 /
Win7-64
EVGA X79 - Classified, iCore7 3930k 32Gb Quad-Channel
950Gb (2 x 500Gb Sata III SSD RAID0 Adaptec 6805E Controller)
Nvidia GTX-690 Classified - 335.23
SpacePilot Pro 3.17.7, 6.17., 4.11
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GSE_Dan_A
Posts: 303
Registered: ‎10-06-2011
Message 9 of 46 (829 Views)

Re: FEA 64 bit problem

11-18-2013 06:30 AM in reply to: ing
This scares the bejeezus out of me (and I am sure many others). I suppose it is a good thing to NEVER take the results at face value. It is good practice to always make a prediction of where the stresses should occur and how the members will deform (compression, tension, bending, etc...)
GSE Consultants Inc.
Windsor, ON. Canada
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JDMather
Posts: 26,543
Registered: ‎04-20-2006
Message 10 of 46 (818 Views)

Re: FEA 64 bit problem

11-18-2013 07:16 AM in reply to: GSE_Dan_A

It would be useful to have the actual part files that these results are taken from.

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