Zerolength Element's Output

[ehsanomranimemphis]

I have modeled a bridge. For modeling of abutment, I employed a zerolength element. I used the following recorder to find what the outputs present:

recorder Element -xml $dataDir/abutmentele18.out -time -ele 18 deformation

When I check the output file, the following phrase can be seen:

<?xml version="1.0" encoding="UTF-8"?>
<OpenSees
xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation = "http://OpenSees.berkeley.edu/xml-schema ... enSees.xsd">
<TimeOutput>
<ResponseType>time</ResponseType>
</TimeOutput>
<ElementOutput eleType="ZeroLength" eleTag="181" node1="111" node2="2">
<ResponseType>e1</ResponseType>
<ResponseType>e2</ResponseType>
</ElementOutput>
<Data>
0.01 9.74191e-011 -1.46244e-010
0.02 -2.69449e-010 4.32871e-010
0.03 -3.17292e-009 5.00567e-009
0.04 -8.81755e-009 1.32235e-008
0.05 -1.42054e-008 1.76341e-008
0.06 -2.01762e-008 1.76144e-008
0.07 -3.01113e-008 2.1682e-008
0.08 -4.07991e-008 2.77183e-008
0.09 -4.87817e-008 2.7402e-008
0.1 -5.81273e-008 2.60095e-008
0.11 -7.02691e-008 2.98138e-008
0.12 -8.04461e-008 3.13579e-008
0.13 -8.92412e-008 2.75186e-008
0.14 -1.01152e-007 2.66261e-008
0.15 -1.13834e-007 2.85532e-008
0.16 -1.23893e-007 2.58323e-008
0.17 -1.34789e-007 2.2054e-008
0.18 -1.47941e-007 2.33833e-008
0.19 -1.58989e-007 2.44374e-008
0.2 -1.681e-007 2.19983e-008
0.21 -1.79173e-007 2.28144e-008
0.22 -1.90183e-007 2.74403e-008
0.23 -1.98058e-007 2.96007e-008
0.24 -2.05917e-007 3.1743e-008
0.25 -2.15221e-007 3.89872e-008
0.26 -2.22079e-007 4.6809e-008
0.27 -2.26462e-007 5.2033e-008
0.28 -2.31921e-007 6.00715e-008
0.29 -2.36813e-007 7.14425e-008

First column presents time. But I don't know what are two other columns. What means e1 and e2? Can someone tell me about e1 and e2?
Thank you very much in advance.

[ehsanomranimemphis]

Is there anyone to help me?

[fmk]

it is the element deformations in each of the 2 dof direcions: e.g. Node2.Disp(dof) - Node1.Disp(dof), Node2.Disp being vector of displacements at node 2.

[ehsanomranimemphis]

fmk wrote:
> it is the element deformations in each of the 2 dof direcions: e.g.
> Node2.Disp(dof) - Node1.Disp(dof), Node2.Disp being vector of displacements
> at node 2.
Thank you. You mean the second column presents displacement in node1 and third column shows displacement in node2?
If so what direction it shows?

[selimgunay]

You can just record the node displacements and subtract them to get the zerolength element deformations

[ehsanomranimemphis]

Thank you. I did it before but there is a problem with that. Actually the first, I defined 3 nodes with same coordinate (node 1 , 2 and 3) and defined two zerolength elements: first one is for abutment and between nodes 1 and 2; second one for shear key and Impact element between nodes 2 and 3. Node 1 was fixed. When I record the results (displacement in node 2 and 3) I get the same values. I mean displacement in shear key and abutment is the same. Why the values obtain similar?
After that, I decided to get element deformation. But in deformation I don't know what means the columns I mentioned in previous post.

[selimgunay]

Theoretically you should get the same results from the two options, otherwise it may indicate a problem in the model. It looks like your deformations in the first 0.3 sec are quite small, is it like that for the rest? That may explain the same displacements of nodes 2 and 3.

[ehsanomranimemphis]

selimgunay wrote:
> Theoretically you should get the same results from the two options,
> otherwise it may indicate a problem in the model. It looks like your
> deformations in the first 0.3 sec are quite small, is it like that for the
> rest? That may explain the same displacements of nodes 2 and 3.
Thanks for your answer. Yes, the rest are small too. But displacement in nodes are bigger.
If the displacement in two nodes is same how I can obtain displacement in abutment and shear key?
I don't know yet what zerolenth element outputs show? (column 2 and 3 in my first post)

[ehsanomranimemphis]

Can someone help me?
I really need to help.

[fmk]

BACK TO MY POST and your response ..

the second column was not the displacements at node 1 and the third the displacements at node 2 .. each column is the difference between the displacements at node 2 and those at node 1 for a particular dof .. you have defined the zerolength element with -dir a b .. so first column is the displacement at the elements second node in the a'th dof minus the displacement at the elements 1 node in the a'th dof ..

[ehsanomranimemphis]

fmk wrote:
> BACK TO MY POST and your response ..
>
> the second column was not the displacements at node 1 and the third the
> displacements at node 2 .. each column is the difference between the
> displacements at node 2 and those at node 1 for a particular dof .. you
> have defined the zerolength element with -dir a b .. so first column is the
> displacement at the elements second node in the a'th dof minus the
> displacement at the elements 1 node in the a'th dof ..
Perfect. Thank you so much. I wanted this exactly.