How well does FEA predict real world
How well does FEA predict real world
(OP)
Has anyone validated their predicted FEA stresses or displacements with simulated testing? If for example, you wanted to validate the deflection of a simple rectangular cantilevered beam, how close could you predict displacement? Within 20%, assuming of course you accounted for infinite stiffness, material tolerances, modulus changes, load cell deflection, misalignment? Is it possible to mimic within 10% using a linear FEA solver and a good test setup, assuming you stay in the small deflection region. I have read articles in trade magazines on this manner, but have not heard what the majority of FEA user experiences has been. I too realize this is a luxury to be able to test your FEA results, due to time crunches, etc.





RE: How well does FEA predict real world
RE: How well does FEA predict real world
RE: How well does FEA predict real world
RE: How well does FEA predict real world
RE: How well does FEA predict real world
RE: How well does FEA predict real world
RE: How well does FEA predict real world
Could you explain coupon testing? Are you referring to standard tensile bars?
Thanks.
RE: How well does FEA predict real world
RE: How well does FEA predict real world
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: How well does FEA predict real world
RE: How well does FEA predict real world
TTFN
RE: How well does FEA predict real world
What inputs are you referring too? Loads or Restraints or Mesh or Material Properties? Could you define failing miserably? What methods do you use to predict deflections then, experimental such as strain gages, etc?
RE: How well does FEA predict real world
Failing miserably as in a predicted deflection of 20 microradians and getting milliradians instead. Measured with theodolites.
TTFN
RE: How well does FEA predict real world
http://www.feadomain.com/content.php?article.48
RE: How well does FEA predict real world
Often it is easy to blame the model, because the solid data does not lie (although it can be deceiving or not reporting what you are looking for), but as IRstuff pointed out, the output has a lot to do with the input.
RE: How well does FEA predict real world
The best test data (the most difficult to mess up) is free-free modal data. However that is also the sort of test that bears the least resemblance to the actual operating conditions. The checks that can be done on a modal survey are quite thorough, so the test engineer can be quietly confident of his results long before the FEA people get involved.
I'd have to say >75% of the time the FEA model is mostly to blame for significant differences between test and analytical results. And it is very rarely a coding problem.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.