Compression only elements

lucariga

Hi,

I'm tring to model a semplified 2D pin element using RBE and CBAR with rotational dof release along the normal to plane.

Due to geometrical and load condition the RBE express a tension/compression on dipendent nodes.

my question is: si possible using an element (such as rbe) that is rigid in compression and not rigid (deactivated?) in traction?

 

 

Rahul Rajan_21763

Try PBUSD1D of type SPRING . You can specify different tables for spring stiffness in tension and/or compression. And specify very high stiffness for compression.

 

lucariga

Hi Rahul,

I'm a new user on Altair, could you provide a simple example (a model) of this method?

thanks

Rahul Rajan_21763

Please refer attached fem deck to get idea.

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Merula_20758

Hi!

 

I digged a bit deeper into it and maybe this can be useful.

So if I am not wrong on this, first thing for this to work is, that you have a non-linear subcase (non linear static for example) with a NLPARM card.

 

I went into some problems when defining the stiffnes to be completely zero for tension, but that seems to be a model issue only related to the simple example.

 

I attached the modified .fem file for future reference (also for mysel if I want to look it up again /emoticons/default_wink.png' srcset='/emoticons/wink@2x.png 2x' title=';)' width='20' /> )

 

Have a nice day!

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