Measures not Available in Dynamic Frequency Analysis Results Window Definition

[ptc-5183982]

I am attempting to run a dynamic frequency analysis on a vertical bottle. I define everything, in that the modal and static give good results. I am a little hesitant on how exactly the DFA works (as far as what the inputs are, I've done this in other software), but that is not really the question here, as I am sure I can figure it out once I start seeing results.

After my DFA completes, I go to display results and the options available to me are very limited. It must be a graph and ordinate must be a measure (with abcissa freq/measure). The problem is, even though there are predefined measures, and I have defined measure that are compatible with DFA and DTA, there are ZERO measures available to choose from. Where are the measures? Searching for answers is difficult as I am always directed to rants about the measurement tool.

I also found that this was a problem, with apparently not solution in Wildfire?

https://www.ptc.com/appserver/cs/view/solution.jsp?n=CS149627&posno=6&q=dynamic%20frequency%20analysis&nav=&source=Search

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[sdensberger · Accepted solution]

In a dynamic frequency analysis, there are not defult measures initially defined. If you do create measures and want to plot them against frequency, then you need to make sure that you've selected "At Each Step" under the "Dynamic Evaluation" section of the measure definition window.

[ptc-5183982]

Thanks Shaun,

It was indeed the 'at each step' that needed to be checked. At least I can get results now. Now I am just having trouble finding comprehensive instruction to explain all the different parameters...

[sdensberger]

Any one in particular you'd like explanation on?

[ptc-5183982]

I am just having a hard time with dynamic [frequency] analysis itself, and neither the official or 3rd party resources are very useful, and often focus on the 'Mechanism' side of things rather than the Simulate side. I'd rather be introduced to a comprehensive cover of the dynamic analysis and self-direct than have to come back to the forums all the time. It seems a little inefficient, yet even the forums don't house a lot of questions on the DFA.

I have done a lot of dynamic analysis, but in beam-element modeling (AutoPIPE); this is a far cry. Translating how I think it should work is not as easy as I thought it would be.

[DenisJaunin]

Hello, Curran,

Is this link can help.

Best regards.

Denis.

http://communities.ptc.com/message/243355#243355

[ptc-5183982]

Okay, for example, when defining a base excitation amplitude, there seem to be three places to do this

• The direction vector, which I assume is intended to be a unit vector, but does this scale the excitation amplitude?
• The 'Value', which as an aside, I am confused why only acceleration units is available
• The magnitude of the function definition

It seems like a poor design to have so many superimposed inputs, is that really what is happening? There are no resources that explain this. It is a poor help manual explains that the inputs titled 'direction' "define the direction". Thanks PTC...