Contact body analysis sol101

[jedstress]

Hello,

I would appreciate it if someone could give me advice regarding constraint requirements in sol101 contact body analysis. So I have a rectangular plate clamped around its edges. An unconstrained cylinder is pushing down on it using a force card. Contact bodies have been defined. Is that sufficient or does the cylinder require minimal constraints to avoid rigid body motion is sol101? Currently the f06 shows that the model is running but isn't converging i.e. keeps stating detection of node penetration and continues iterating. So I have to abort the job everytime.
Is this a sign of an unconstrained body?
Thanks in advance.

 

[karachun]

Yes,

cylinder require minimal constraints to avoid rigid body motion is sol101

in all directions except direction of pushing. You can replace force with enforced displacement (enf motion is a constraint applied like load) and you model become absolutely constrained.
In addition, it is possible to add manually a couple of springs with low stiffness i.e. "Weak springs" and constrain them. Some FEA packages like SW Simulation or ANSYS use weak spring as default option for free models.
It is possible to use Inertia Relief but I don’t know how it work with contact.

 

[jedstress]

Hi Karachun,

Thanks for the feedback. I can't use enforced displacement because the displacement is unknown. And you mentioned constraining the degrees of freedoms except for the load direction. Wouldn't that still give rigid body motion in the load direction? Typically that's the case in normal sol101 runs.

 

[karachun]

You can use displacement and check constraint force and make a couple of iterations to achieve displacement that produce force you need.
As for second question (constraints in load dir.) I`m not 100% sure but this may work, you can try it by yourself. Contact may constrain model in load direction.

 

[dfreire]

I think that once the contact is achieved, constrain the cylinder in the load direction should not be necessary, because the plate has already been constrained and with the contact both components will work together.