RE: [PSUBS-MAILIST] FEA

[Tim Reilly <TimR@cclengineering.com>]

Thanks 

Tim R.

-----Original Message-----
From: Sean T. Stevenson [mailto:sts@telus.net]
Sent: Thursday, March 20, 2003 9:03 AM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] FEA


Tim, I think ALGOR makes a seamless FEA plugin for Inventor, although I have
not used this myself.  I also do modelling in Inventor, but primarily use
IDEAS for FEA.  If the models you are analyzing are very simple, Mechanical
Desktop has some limited FEA functionality within it.

Be careful with FEA, though.  It's all too easy to assume that the numbers
the system spits out are correct.  You need to make some concerted reality
checks, since no matter how complex the load case you define is, it
typically is only an approximation of reality.  Your FEA model will be
different than the actual prototype, since you typically eliminate such
features as weld fillets and minor holes - features which may have little
bearing on strength, but are a significant factor in stress concentration
and fatigue life.  You need to consider such things in addition to the FEA
results.

Good luck.

-Sean


Quoting Tim Reilly <TimR@cclengineering.com>:

> Is there a cheap program or share ware program that I can get to do this.
> 
> The cad programs I currently use are Autodesk Inventor 5.0 and Autocad
2002
> 
> Thanks again 
> 
> Tim R.
> 
> -----Original Message-----
> From: jbarlow@bjservices.ca [mailto:jbarlow@bjservices.ca]
> Sent: Thursday, March 20, 2003 8:12 AM
> To: personal_submersibles@psubs.org
> Subject: Re: [PSUBS-MAILIST] FEA
> 
> 
> 
> Finite Element Analysis.
>       A virtual model of an object is "built" in a computer and the
program
> breaks it down into a finite number (but very large number) of pieces
> (elements) which have the applied material properties and interact with
> their neighbours.  An operator then applies a load and (mostly pressure in
> this case) the program will spit out the stress that each area of the
model
> in under.
> The reality of the answer relies on the way the model is built up, the
> correct placement and magnitude of the applied loads by the operator.  You
> can get orders of magnitude difference between answers by slightly
changing
> the applied loads and the method of model construction.
> 
> 
> Jay.
> 
> 
> 
> 
>  
> 
>                       Tim Reilly
> 
>                       <TimR@cclengineering.com>         To:
> "'personal_submersibles@psubs.org'" <personal_submersibles@psubs.org>
> 
>                       Sent by:                          cc:
> 
>                       owner-personal_submersible        Subject:
> [PSUBS-MAILIST] FEA
> 
>                       s@psubs.org
> 
>  
> 
>  
> 
>                       20/03/2003 08:53 AM
> 
>                       Please respond to
> 
>                       personal_submersibles
> 
>  
> 
>  
> 
> 
> 
> 
> 
> Please forgive my ignorance, but what is FEA as refered in this message?
> 
> Thanks
> 
> Tim R.
> 
> -----Original Message-----
> From: Warren Greenway [mailto:opensourcesub@yahoo.com]
> Sent: Wednesday, March 19, 2003 9:57 PM
> To: personal_submersibles@psubs.org
> Subject: Re: [PSUBS-MAILIST] OSS Pressure Hull, DoubleEndcap
> 
> 
> You rock. Thanks for the rendering, that is cool.
> A detailed 2D drawing would be great. It is Cosmos
> FEA that is really giving me the headaches. I have
> to rebuild all of the hull as a series of swept
> features to run the FEA. Not a huge deal, but I have
> been insanely pressed for time. I am working on it,
> though. I think this hull has the potential to give
> you high speed, if you want it. Hey, Pierre, you
> have any luck with FEA on this?