Tied contact with stiffness value

Altair Forum User

Hi, 

 

With the LS-dyna solver it is possible to define a 'tied' contact with a stiffness value; the nodes are not rigidly attached but can move towards each other by producing a reaction force. Is that possible with Radioss? I try to connect nodes of two solid element together with this contact. 

 

Thanks in advance! 

Altair Forum User

Hi,

Please try with Spotflad=26 and a reduced Stfac value (Default is 1, you can try with .05 as an example) in the Type 2 interface card. 

Altair Forum User

Hi George, 

 

Do you mean Spotflad = 126 because there is no Spotflad 26?

My issue is the following: I have a model with an average element length of 3mm. But now I need to add a thin layer of 0.15mm elements. In order to prevent killing my time step I thought it is possible to not solid-model that thin layer but leave it as a gap with a contact that has a stiffness value that correspondsto the one of that layer. Or what would be the correct way to do it?

 

 

Altair Forum User

Hi,

As a workaround, you can try creating spring elements (Type 13) between the plates where you can provide the  stiffness value  to the spring element. And  create Type 2 interface between the spring nodes and plate.

You can watch this webinar which shows creating spring elements in RADIOSS: https://www.youtube.com/watch?v=-HdECgBC_lM&list=PLQ7KUGFuVz4u5y3SvIEIU07427-gATaG6

 

Altair Forum User

Springs cannot be attached to solids, right? So the idea is:

 

1. create a shell above the solid 

2. connect shell with type 2 contact to the solid

3. connect upper and lower shell with springs type 13

 

Is this the correct and easiest way to accomplish it? 

 

Thanks! 

Altair Forum User

Hi,

You can connect using springs for solid elements. And you can try with the above mentioned method.