Dynamic stiffness analysis

Altair Forum User

Hi all,

 

i need to calculate a dynamic stiffness in a frequency response analysis.

 

The term stiffness is defined as follows:

 

i have a structure (free from RB-modes) and i put a force load on a node in it, which must vary sinusoidal with time. The force load will deform the structure and i want to monitor the deformation of a certain node in the structure, which lies a distance away from the load point. The stiffness now is calculated as force / displacement.

 

What i need for postprocessing is the stiffness-value described above plotted over a frequency domain for the force of about 50 Hz to 10 kHz. Is that possible in RADIOSS Bulk? How do i model the loading? Which Output requests will deliver the needed values from the Solver?

 

Many thanks in advance

Bhoopal

Hi Florian_lw

 

Good day,

Your post was years ago, hope you might have extracted the dynamic stiffness from the frequency response analysis.

From my point, I just came across this problem to find the dynamic stiffness from FRA. I have done a 1N load excitation at the base state & response of displacement at intended points noted over required frequency range. A 1 N unit load divided with the displacements will give the stiffness across the frequency range. The minimum the displacement, maximum will be the Dynamic stiffness in that particular direction. Hope I answered your query,

 

I heard that in Radioss, there is a Channel method to extract dynamic stiffness, Can anyone please share the info., on it.

 

PS: Better LATE than NEVER ... /emoticons/default_smile.png' srcset='/emoticons/smile@2x.png 2x' title=':)' width='20' />

 

Thanks 7 regards,

Bhoopal