Eigenmode analysis output only high frequency

[pmanandhar]

Hi,

I am working with ultrasonics and I regularly do eigen-analysis in PTC Mechanica where one can input start and end frequencies for eigen analysis and get modes between those freuqencies.

For Elmer, in the "Stress Analysis" linear elastic module, the Eigen System Values paramter is useful. However if I start at 0, and I need say 100kHz, I would need to have 100s of modes, taking a lot of memory and time and also the results file would be huge for a complex shape.

Is it possible to do the analysis just in a small range say between 20kHz to 30kHz in Elmer?

I am looking at the Helmholtz module, but I want to keep doing this with the linear elastic system rather than change the equations.

Thanks in advance,
Prakash Manandhar
Department of Bioengineering
University of Massachusetts Dartmouth, USA

[raback]

Hi

Solver manual p. 36 should have the keywords:
http://www.nic.funet.fi/pub/sci/physics ... Manual.pdf

Unfortunately "Eigen System Shift = Real" was missing, and I added it. Just give the value (2*pi*20e3)^2 for this and you should get only eigenfrequencies in the desired range.

-Peter