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Simulation cauchy cube

Posted May 16, 2015, 2:43 a.m. EDT Structural Mechanics 2 Replies

Alessandro Sitta
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Hi,
I try to simulate the deformation of a simple cube without any boundary conditions but in static equilibrum( sum of resulting force and moments are zero, for example applying two forces equals and opposites on two opposite faces of cube ).
The simulation doesn't work for error in convergence, as the system is not in equilibrium, while really it is in equilibrium (it hasn't any DOF).
Could anybody help me?

Thanks,
Alessandro Sitta
2 Replies Last Post May 16, 2015, 8:22 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 9 years ago May 16, 2015, 6:13 a.m. EDT
Hi
What you are trying to do is feasible in theory, but hardy feasible with the numerical representation of number in our computers, the rounding errors will make small differences and your cube will start spinning or moving => hence a the convergence error.

The easiest with a cube is to study 1/8 and use 3 symmetry planes, and apply only one force that, by symmetry will by applied exactly from the other side (in 2D its 1/4 with 2 symmetry planes)

--
Good luck
Ivar
Hi What you are trying to do is feasible in theory, but hardy feasible with the numerical representation of number in our computers, the rounding errors will make small differences and your cube will start spinning or moving => hence a the convergence error. The easiest with a cube is to study 1/8 and use 3 symmetry planes, and apply only one force that, by symmetry will by applied exactly from the other side (in 2D its 1/4 with 2 symmetry planes) -- Good luck Ivar
Alessandro Sitta
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Posted: 9 years ago May 16, 2015, 8:22 a.m. EDT
1/8 th model works perfectly!

Thanks for the help,

Alessandro
1/8 th model works perfectly! Thanks for the help, Alessandro

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