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bistable beam simulation

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Hi everyone,

I was wondering if anyone has ever modeled a simple beam that has bistable stability, whereby if a point load is applied to the centre of the top of the beam, forces it to buckle downwards and stay down even after the load has been removed, and vice versa in the opposite direction.

Any and all help would be greatly appreciated.

Regards,

Nixon.

1 Reply Last Post May 23, 2016, 2:38 p.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 8 years ago May 23, 2016, 2:38 p.m. EDT
Hi

if you take a simple straight beam and apply an increasing load at the end you can get it to buckle, but you must turn on non-linear geometry in the solver and ideally give it a little extra kick to get it off the straight line. There is a model/application library example that is a good start of a largely deformed beam.

When you have a catastrophic buckling (sudden collapse) you will not see the fully hysteresis cycle, you might need to load and then unload in a second stationary sweep study, starting from the collapsed beam. Another way to go through a buckling case is to impose an increasing displacement and derive the reaction forces and moments. This allows one to better follow the full path, but the model might not solve. Do also check the best solver settings for non-linear geometrical structural stationary solver, from the KB, Blog and other Forum threads

--
Good luck
Ivar
Hi if you take a simple straight beam and apply an increasing load at the end you can get it to buckle, but you must turn on non-linear geometry in the solver and ideally give it a little extra kick to get it off the straight line. There is a model/application library example that is a good start of a largely deformed beam. When you have a catastrophic buckling (sudden collapse) you will not see the fully hysteresis cycle, you might need to load and then unload in a second stationary sweep study, starting from the collapsed beam. Another way to go through a buckling case is to impose an increasing displacement and derive the reaction forces and moments. This allows one to better follow the full path, but the model might not solve. Do also check the best solver settings for non-linear geometrical structural stationary solver, from the KB, Blog and other Forum threads -- Good luck Ivar

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