Natural frequency analysis
Natural frequency analysis
(OP)
Hi,
I got my natural frequencies from Siemens NX and went in FEMAP to obtain the plot of my peaks at those frequencies. The problem is that I am new to this and I don't know how to get a good plot. I watched a lot of tutorial but nothing is working. Here's a description of my analysis:
- A CubeSat fixed on one end (4 tips)
- Frequency range: 20 to 2000 Hz
- First natural freqeuncy: 211.218 Hz
Note: I am only analysing the structure with no added mass
I got my natural frequencies from Siemens NX and went in FEMAP to obtain the plot of my peaks at those frequencies. The problem is that I am new to this and I don't know how to get a good plot. I watched a lot of tutorial but nothing is working. Here's a description of my analysis:
- A CubeSat fixed on one end (4 tips)
- Frequency range: 20 to 2000 Hz
- First natural freqeuncy: 211.218 Hz
Note: I am only analysing the structure with no added mass

RE: Natural frequency analysis
another day in paradise, or is paradise one day closer ?
RE: Natural frequency analysis
RE: Natural frequency analysis
another day in paradise, or is paradise one day closer ?
RE: Natural frequency analysis
Thanks
RE: Natural frequency analysis
another day in paradise, or is paradise one day closer ?
RE: Natural frequency analysis
RE: Natural frequency analysis
RE: Natural frequency analysis
you have asked for displacement at each node, but can't plot the deformed shape ?
another day in paradise, or is paradise one day closer ?
RE: Natural frequency analysis
When I put the excitation in the X axis I get this for acceleration and displacement:
The peak is at a frequency of 190 Hz instead of 211 Hz as I was expecting with the X excitation and I dont understand why it doesn't start at 0 displacement?
RE: Natural frequency analysis
My natural frequencies are suppose to be:
Does it make sens or not at all?
By the way thanks for your answers rb1957
RE: Natural frequency analysis
or are you rerunning someone else's model ?
this thing is 350mm tall ?
your tables are confusing to me ... is ordinate "350" the top or the bottom of the model ? (the restrained end or the unrestrained end)
Not sure why none of your results look like the plot you want (17:19 on the 18th Nov, showing the maximum response of a input (ay = 0.25g) ?
another day in paradise, or is paradise one day closer ?
RE: Natural frequency analysis
(100 x 100 x 200) mm
I fixed one end and put my excitation at the same end. I look at 1 node at the other end. In my graphs, x axis is the frequency and y axis is the acceleration. My frequency range is 20 to 2000 Hz. In my last post I put a word file if you didn't see it. But I got somethnigs to change still.
RE: Natural frequency analysis
another day in paradise, or is paradise one day closer ?
RE: Natural frequency analysis
Take a look to this post and you will learn how to perform a modal frequency response dynamic analysis (SOL111) using FEMAP & Simcenter Nastran:
https://iberisa.wordpress.com/2020/01/07/analisis-...
Best regards,
Blas.
~~~~~~~~~~~~~~~~~~~~~~
Blas Molero Hidalgo
Ingeniero Industrial
Director
IBERISA
48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog de FEMAP & NX Nastran: http://iberisa.wordpress.com/