Time history (/post26) Seqv Beam188

[Sjoonus]

Hi,

I'm performing a (seismic) analysis of a container crane. The loads are working, but now I'm trying to read the (time history) results. Using the time history post processor (/post26), I only can get the Nodal (Dof) solutions. I want to get Element solutions, e.g. VonMises stresses in certain elements of my used Beam188, but it gives no valid answers.

What am I doing wrong if I use the following:

ESOL,2, 108, 55,s,eqv ! Element solution (variable nummer = 2) of element 108 at node 55, stress, VonMisses eqv
ESOL,3, 112, 63,s,eqv

PRVAR,2,3 ! Store and then print variables 2 and 3
PLVAR,2,3 ! Plot the variable 2 and 3

 

[JoshPlumSE]

Sjoonus -

I'm not familiar with our specific program at all. But, most of the time, the analysis programs will NOT saved all the results data for each time step.... That's just too much data to save.

What you usually have to do is Pre-define a "trace" of what data you want to look at and then run your analysis. Then you can look at those results as a graphed function of time (the trace).

Does that make sense? My company will probably be adding time-history analysis to our program some time in the not-too-distant future. So, I'd be interested in what type of results and input you folks are really interested in. My companies goal is always to make the input as user friendly as possible. So, we really, really try to understand the feature from a design engineer point of view before we implement it into the program.... otherwise, you're left with a more "academic" application which is better for students and professors than it is for practicing engineers.

 

[Sjoonus]

Dear Josh,
Tnx for the fast reply. I also think (at this moment) the problem is the result data is not saved yet. Do you know how to do this with Ansys10?

Can I for example use a table to write it to, like,

*dim,results,table,1200,1 !create table 1200*1 named 'results'
*get,results,NODE,201,S,EQV !stores the VonMises equivalent stress of node 201 in the created table 'results'

Or is it not possible in this way? Should I create a ETABLE maybe?
Could someone help me with this? Tnx

@Josh
For time history analysis, for me it is important to be able, as input, to read (from external file) an dynamic load spectrum, and, as output, to plot, list (and export) the VonMises stresses and displacements of defined nodes and/or elements. It should be easy if the maximum and minimum of these stresses and displacements are listed directly with the corresponding time/freq.

 

[JoshPlumSE]

I can't help you much further as I have little knowledge of Ansys. But, there has to be away.... other wise I would think the time history analysis would be practically useless.

There is another forum on Eng-Tips titled "finite element analysis engineering". There may be more Ansys folks on that forum who could answer your question.

For what it's worth, it sounds like you want to use your time history analysis to produce an "in-structure" response spectrum at a given point. That is a little more advanced. Not all programs will produce that type of output.