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Can comsol really not model a pendulum?

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Seems like a simple question, but I've had no luck so far... Any ideas?

I want to find the pendulum frequency of a model hanging from a fixed support, ie, the object is in a gravitational field. Can comsol even do this?

2 Replies Last Post 5 nov 2011, 05:01 GMT-4
Nagi Elabbasi Facebook Reality Labs

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Posted: 1 decade ago 4 nov 2011, 23:39 GMT-4
You can to model the pendulum body with a stiff material, constraint part of it to a rigid connector point. Then fix the translation of that point, keep one rotation free, add gravitational body force and perform a transient analysis. Include geometric nonlinearity if you want to account for the effect of large pendulum angles.

Alternatively, you can implement the pendulum equation of motion directly using the equation based modeling capabilities of COMSOL!

Nagi Elabbasi
Veryst Engineering
You can to model the pendulum body with a stiff material, constraint part of it to a rigid connector point. Then fix the translation of that point, keep one rotation free, add gravitational body force and perform a transient analysis. Include geometric nonlinearity if you want to account for the effect of large pendulum angles. Alternatively, you can implement the pendulum equation of motion directly using the equation based modeling capabilities of COMSOL! Nagi Elabbasi Veryst Engineering

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 5 nov 2011, 05:01 GMT-4
Hi

probably the simplest is to use a euler beam (2D and 1 line to draw, then as Nagi said, attach one point but let rotations free, and add a virtual mass at the other end.

If you draw the line with an angle (parametris a rotation in the geoemtry) you can change the initial starting point. And with gravitational forces you have everything you need ;)

--
Good luck
Ivar
Hi probably the simplest is to use a euler beam (2D and 1 line to draw, then as Nagi said, attach one point but let rotations free, and add a virtual mass at the other end. If you draw the line with an angle (parametris a rotation in the geoemtry) you can change the initial starting point. And with gravitational forces you have everything you need ;) -- Good luck Ivar

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