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Shaft stress analysis - deformation error

Daboa

New member
Hi all,







I'm designing a shaft for a turbine and I
need to know the stresses it will feel as the rotor assembly rests and
accelerates on it. As shown here, it's supported by two bearings on
each end and the hub in the center will connect to rotor blades that
will turn as air moves through a wind tunnel.


vgamT.jpg




The
end goal is to maybe hollow out the 1-3/8" shaft to minimize weight,
but we need a stress analysis. Here's a picture of the bare shaft in
Pro/E. I can see grooves for snap rings.



AxDyX.jpg



I
tried running a test in Pro/E's Mechanica, but encountered an error
that I couldn't figure out (something about edges), so I moved to
solidworks. Here's what I did. First, I chose material (Al 6061) and
applied constraints in the snap ring grooves because specifying the
bearing locations proved difficult and I just wanted to see if I could
get any analysis done first. I chose a "hinged" constraint because I
want the shaft to only rotate about its axis. I applied this constraint
(shown) at all four snap ring grooves.


uNieU.jpg




I
then applied a torsional load around the middle of the shaft where the
hub would be connected. I also applied a weight force for the weight of
the rotor assembly here.


CtKNc.jpg



So in the end, here's what the shaft with simulation specifications looks like.


dzDLu.jpg




Then
I mesh and run it. I get 27.3% into the analysis before an error pops
up saying "Deformation for this study is too large to be realistic..."
(shown here).



0epLl.jpg




Choosing
to stop cancels the analysis and I don't know what to do. Choosing to
continue makes the simulation run for a while. Yesterday, it finally
ended and gave me an error about strain being > 25%, which is
obviously not good. Today, it's been running for 22 minutes and nothing
has happened. Weird.


EDIT: I just noticed the window. It popped up underneath something. Here it is. The study terminates when I click okay.

Ed1dw.jpg








So what am I doing wrong? What am I missing and what do I need to change. I'm open to all suggestions. Thanks a lot.















Edited by: Daboa
 

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