Effect of RBE3s on stiffness

RBE3 element has NO stiffness.

If you wan to add stiffness, try rod,bar, beam,...

are you continuing this topic?

https://forum.altairhyperworks.com/index.php?/topic/23230-contraining-a-hole-as-a-void-that-will-not-expeirence-deformation/

I suggest you try modeling a shaft and make it contact tied with hole of bracket

Hello,

If you have particular stiffness values you want the hole to have, you can also try using GAP elements or CBUSH.

Hi all,

Thank you for your responses. This has helped with my understanding.

I suggest you try modeling a shaft and make it contact tied with hole of bracket

If I am to try to model a bearing I will use this method.

If you have particular stiffness values you want the hole to have, you can also try using GAP elements or CBUSH.

I do have a radial stiffness value. I will try and use these elements and input the stiffness values. Is it possible to use CBUSH or GAP elements as a spider that is constrained in the middle (like a RBE2 or 3 element spider)?

Thanks

try it! you can use cbush spider but i think no need to constraint its center

Hi @tinh,

I did try both methods.

The panels for spring and bar elements do not have an option to create a 'calculated node' from nodes selected on a surrounding face - like there is with the rigid and RBE3 element panels.

Hence, my question was, is it possible and if so, how?

Thank you

Just create the center nodes and bind it to hole by spring/bar

As @tinh said create a center node.

You can do it by Geom>>distance.

<?xml version="1.0" encoding="UTF-8"?>

Select three nodes of circle and click on circle center

Hello,

Thank you for your responses. I will create the centre node using this method.

However, is it possible to select all the surface nodes on the inner surface of the hole in one go?

As from what I can tell I will have to select each node individually and connect this to the centre node to create a spider.

Thank you

there is a tcl script that changes rbe spider to bar/spring spider. I remember someone asked for it on this forum.please search it

Thanks @Tinh,

I came across this, but it seems to just be available to Altair clients - which I am not.

https://forum.altairhyperworks.com/index.php?/topic/13205-hyperworks-script-exchange/

Is there a better/easier way to add a defined amount of (radial) stiffness to a cylindrical hole?

Thank you

make a cylindrical system, assign it as disp system of the nodes and constraint their 1st dofs (r)