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Solid body contact breaking? (Ornithopter design)

Question asked by Alex Mastro on Jan 10, 2012
Latest reply on Jan 10, 2012 by Alex Mastro

Hi forum members,

 

I am having a problem where the solid body contact constraint that I've introduced is breaking when the oscillation frequency of my simulation becomes too high.

 

I am trying to simulate the beating action of ornithopter wings.  I am using a "motor" to drive the two "cams" which convert the rotation motion in oscillatory motion.

 

I tried to design the hinge mechanism along the wing so that there would be stops to prevent the "elbow" from hyperextending.  I added a solid body contact constraint between the two elbow pieces.  It seems that this constraint is being ignorned when I drive the motor at too high a frequency.  I'd like to be able to observe the flapping conditions at 10 Hz (600 rpm motor speed)

 

I've placed a torsion spring & dashpot at the joint.  The spring is to help the wing return to parallel alignment by the end of upstroke, and the dashpot is to simulate wind resistance.

 

Anyone want to take a look?

 

I have attached the project files.

 

The picture below shows how the incorrect hyperextension is occuring at the end of upstroke.

 

http://i.imgur.com/zSqqYl.png

http://i.imgur.com/E5nu0l.png

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