rigidLink and rigid joint offset

leexian · Post by **leexian** » Fri Oct 24, 2008 11:15 am

hi, can anyone tell me the difference between "rigidlink" and "rigid joint offset"? for example , what's the difference between model 1 and model 2?
thanks a lot.

MODEL1
#define nodes
node 1 0 0;
node 2 0 1200;
node 3 0 1800;
node 4 0 3000;
# supports of columns
fix 1 1 1 1 ;

# Geometric transformation
geomTransf Linear 1
geomTransf Linear 2 -jntOffset 0 0 0 600
geomTransf Linear 3 -jntOffset 0 600 0 0
element nonlinearBeamColumn 1 1 2 10 1 2;
element nonlinearBeamColumn 2 2 3 10 1 1;
element nonlinearBeamColumn 3 3 4 10 1 3;

MODEL2

#define nodes
node 1 0 0;
node 5 0 600;
node 2 0 1200;
node 3 0 1800;
node 6 0 2400;
node 4 0 3000;
# supports of columns
fix 1 1 1 1 ;

# Geometric transformation
geomTransf Linear 1
element nonlinearBeamColumn 1 1 5 10 1 1;
element nonlinearBeamColumn 2 2 3 10 1 1;
element nonlinearBeamColumn 3 6 4 10 1 1;
rigidLink beam 5 2;
rigidLink beam 3 6;

Post by **fmk** » Fri Oct 24, 2008 12:08 pm

in rigidLink the transformation is handled by the creation of MP constraints .. when using joint offsets the transformation is handled by the geometric transformation.

leexian · Post by **leexian** » Fri Oct 24, 2008 3:24 pm

thanks,fmk. but in fact, both "rigidlink beam " and "rigid joint offset" treat the element as a rigid body, i am confused why they have different results.

Post by **fmk** » Fri Oct 31, 2008 11:10 am

also rigidLink just does translational dof .. you might want to try rigidBeam

leexian · Post by **leexian** » Sat Nov 01, 2008 2:37 pm

thanks,fmk. i see now.

leexian · Post by **leexian** » Sat Nov 01, 2008 2:46 pm

also, fmk.do OPENSEES has technical manual? we just have the user manual, it seems hard to know how the commands work.

silvia · Post by **silvia** » Mon Nov 03, 2008 5:19 am

there is the examples manual, but for simple examples.