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Frequency Analysis With Different Materials

Question asked by Noah Clark on Sep 21, 2013
Latest reply on Sep 21, 2013 by Noah Clark

Hi all,

I am very confused with some of the results that I am getting using a static frequency analysis.

Frequency is calculated as the squareroot of stiffness devided by mass (as found here towards the bottom: http://en.wikipedia.org/wiki/Fundamental_frequency).

 

My question: when I run an analysis on the same beam but using a different material, say steel (ASTM 36) vs aluminum (6061 alloy) vs plastic (Nylon 101) I get almost the exact same results (difference of 27.61Hz vs 27.65Hz vs 27.48Hz). Can sombody explaine to me why I might get approximately the same result even though the masses are significantely different fro each of these 3 materials?

 

Thank you in advance!

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