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frequency response analysis

Hello,

I am trying to set up a frequency response analysis for my model.
using the global output request card it is possible to get acceleration and displacement results for a set of nodes.

What I can't figure out is how to get the results for the frequency response for the strain between two nodes???

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HyperMesh

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Rahul_P1

Hi,
output the strain in HyperMesh and follow the steps below:
in HyperView,
1)plot the strain results and change the averaging method to simple
2)on the graphic window right click and select query-->nodes.
3) click the nodes and you should the see the contour value for that node.

this will average the contour results of the elements to the nearest node.

Hope this helps.
you can also get the results from query panel in HyperView.

Rahul_P1

Student_1739

Can you elaborate on what you mean by strain between two nodes? perhaps explain what you need with an image?

Rahul_P1

By strain I mean the mechanical strain wich occurs between two nodes. I want to simulate a strain gauge.

Unfortunately by just adding strain to the output card there is still no frequency response plot in the ***_freq.mvw file.

Why is this only possible with the displacement and the acceleration??

Rahul_P1

Strain gauge measures engineering strain. so you want to get the engineering strain, is it?

True strain= In(1+Engineering strain) where true strain is what you get from FEA analysis. You can use expression builder in HyperView to get the results.

In HyperView click Derived results to write mathematical expression and this expression will be reflected in the result type.

Please refer to the snapshots below:

Rahul_P1

the expression used in the above picture is for Engineering strain.

Please let us know if this is what you are look for!

Rahul_P1

sorry but that ist not what I ment.

what I am already doing is to plot the requency Response for the acceleration for a specific set of nodes in x,y and z direction. Those results are stored in an '***_freq.mvw' file.

I would like to do the same to plot the strain between two specific nodes

Rahul_P1

in STRAIN under EXTRA(1) change it to MECH which will output the MECHANICAL strain for specific node(s), if you specify any node set/all

Rahul_P1

for the strain Output request it is not possible to choose an entity set based on nodes. which makes sense, because a node by it self has no length and therefor no strain.
so I created a set based on an element.

I tried that, but there are still only the plots for the acceleration grids.

Rahul_P1

Student_1739

The strain is written out to the h3d file as well, please go to build plots panel and open the h3d file there, this will have the strain results,

You can also review the .strn file which will have the requested strain data.

Rahul_P1

awesome!

just one final question:

I don't understand the highlighted term XX(Z1)
what strain does this represent?

thank you so much for your help

Rahul_P1

XX is the X tensor direction and Z1 represents the upper layer of shell element and Z2 represents the lower. Z1 and Z2 are different for different solvers.

if you see XY, YZ, ZX components they are the shear components.

YZ and ZX will not be seen for pure bending

Rahul_P1

thank you very much!