EXAMPLE 1 Truss analysis

[yyleno]

Hi,
i considered another question when i run the example 1,truss,,
If i want to consider the node's nonlinearity in this example to analysis dynamic ,how can i assign this nodes.?

hope you help me!

[vesna]

I am not understanding your question. Would you please reformulate it?

[yyleno]

for example ,there is a node 1 in a structure of 3d truss .
now ,i want to consider the nonlinearity of the node 1,
because the turth is if we need get a precise result,we must consider the displacement and deformation about the node.
and then i assign a zerolength link contact the truss and the node,and give the link a constitutive relation.
The question is ,could i use zerolength assign this link ?
If i want to consider all nodes,can i add this link on the nodes,that is a node will have 3 or 4 link,what can i do when i consider the geomtranf?
thanks

[vesna]

yes, you can use zerolenght elements for that purpose.

you do not have to specify geomtransf if your only elements are truss and zeroLenght elements. geomtransf needs to be defined if using beam elements.

[yyleno]

Hi,vesna,
there is another question.
the zerolenth element has been assigned.but when i assign the dofs using the equalDOF command,
i can't understand how to assign the equalDOF's dofs.
for example,i use the simple 3d truss to assign the node 1
first, i assign the nodes. 101 is the x-axis,102 is the y-axis,and the 103 is x-z at 45 degree angle
node 1 0.0 $L 0.0;
node 101 0.0 $L 0.0
node 102 0.0 $L 0.0
node 103 0.0 $L 0.0
second,
fix 1 1 1 1 1 1 1
element truss 1 101 201 0.472 2
thirld,
element zeroLength 17 1 101 -mat 1 -dir 1
element zeroLength 18 1 102 -mat 1 -dir 2
element zeroLength 19 1 103 -mat 1 -dir 1

now, i assign the equalDOF is right or not?

equalDOF 1 101 2 3 4 5 6
equalDOF 1 102 1 3 4 5 6
equalDOF 1 103 2 4 5 6

thanks!

[vesna]

I do not quite understand what are you trying to model. Would you please first describe what you are trying to model and I will then comment on your code.

[yyleno]

happy new year! vesna, then for example, i assign the nodes1,101,102,103,all the nodes have the same coord.
and i assume node1 and node 101 connect a x-axis zerolength element,node1 and node102 connect the y-axis zerolength element,
and node1 and node 103 connect a x-z at 45 degree angle zerolength element.
so node1 is a master node ,and 101,102,103 are slave node,
now i want to use equalDOF command to assign the restrains about the x,y,x-z,zerolength element.

what should i assign??

just like the above equalDOF.

PS: if you can't understand again,pls let me know ,i will paste the example code.

[yyleno]

Hi,vesna,about the 3d truss model,if i have assigned all the zerolength element,should i use equalDOF command to assign the same coord node boundary?
that is ,for example ,i assign node 1,101,102,103 have the same coord,and i use zerolength element connect 1-101,1-102,1-103,how should i assign the 1-101 boundary?