Multi point Constraint

Hi Youssef,

MPC are used to define a relationship between a set of nodes to dependent node (Equation).

For instance, you have a dependent node and you want the X displacement of the dependent node equal to sum of half of X displacement of one of the independent node and twice of Y displacement of another independent node.

in such a case you can use MPC.

Perhaps this webinar on MPC will help, - http://www.altairhyperworks.de/html/de-DE/BestPractice_Recordings/2011/07_May13_Radioss_RBEs_MPCs_index.html

Thank you Rahul , Thank you Prakash  /emoticons/default_smile.png' alt=':)' srcset='/emoticons/smile@2x.png 2x' width='20' height='20'>

Hi,

I have a also question about MPC.

How do I create MPC's in HyperMesh for the RADIOSS Solver?

F.M.

Hi,

I would also like to know how to create MPC in Radioss user profile to model cyclic symmetry.

An example using this type of kinematic constraint would be appreciated. 

Hi Ivan,

For cyclic symmetry in RADIOSS we have a workaround.

Select the nodes where you apply the boundary conditions, and put imposed displacement (/IMPDISP, and keep icoor=1)load on those nodes with zero magnitude function  in the required directions. 

X       Y

0       0

1       0

Thank you for the tip, however I am unable to properly apply this workaround. The reason is this model probably needs node to node constraints like MPC. Could you please look into the files?

Hi Ivan,

Reviewed your files.

The model is not a cyclical symmetry case but a planar symmetry problem. There are some limitations in RADIOSS if you want to continue with planar symmetry.

If your purpose is only to reduce the run time I would recommend you to change the function defined for /IMPDISP load.  That is, instead of ramping the load in 1s you can ramp in 200 or 300ms and run the model for the same time.