rigid link element

[mehdi1995]

Hi
I wanted to model a foundation with a rigid element so i used the rigidlink-beam element command but it seems that it doesn't transmit the forces at all!!is there another way to get a rigid element?i don't want to use an elastic element with big Elastic modulus because of convergence problems!

[fmk]

the rigid elements construct MP constraints. These ensure that the nodal movement is constrained to move as the constraint requires, i.e. if two nodes have a link in the x dirn, they will have the same x displacement.

if you are not seeing the constraint it probably means you are using the Plain constraint handler and ignoring the warnings.

[mehdi1995]

My constraint handler is Penalty Method but the weird thing is that the horizontal nodes which are constrained have the same displacement values but the nodes which is vertically constrained to another node have a little difference in there displacement.

[fmk]

the little difference is due to the Penalty factor .. increase the penalty value and the difference will go away, but watch out for conditioning of the matrix .. just have it big enough so that discrepency does not bother you.