Default values for contact stiffness represantative?

[JeroenDevos]

Hi again,

I have to find the dynamical behavior of a milling machine. Connexions between the different parts are very important and I want to modelise them as realistic as possible. The structures has a couple of bolt connexions.
I use the contact wizard to define the connexion.
I would like to know if you know (by experience) if the default values for the contact stiffness, proposed by ANSYS, are realistic for bolt connexions?

thanks in advance,
Jeroen

 

[Stringmaker]

Jeroen,
Unless you are interested in the hertz stress directly at the interface between where the bolts interact with other structural parts I do not think you will see any appreciable difference in how your model behaves. Generally the default values are "good enough" for most contact situations. Higher normal constact stiffness (FKN real constant) provides less penetration and hence more realistic results. There are other contact real constant which contribute significantly too.
On a side note, if you aren't interested in the stresses caused by contact between the components and the bolts being held in place you may find it easier and more computationally efficient to use beam elements to connect the bolted together parts.

-Brian