Structural Dynamics and Stability

[DM_9837618]

Hi everyone, I think for you it is a piece of cake but I have to ask you something. I would like to calculate matrix K-Lambda M and determine egenvectors W. I tried but my checks are not satisfied. The values are diagonal but they have to be around zero exept 11,22,33. I need the help what kind of functions should I use?

[terryhendicott]

Hi,

Enclosed is a Mathcad 15 file I have found useful for vibrating beams.

Ask nicely and it probably can be converted to Prime with a bit of work.

The function you are looking for is Gamma=genvals(Kg,Mg)  where Kg is the global stiffness matrix and Mg is the global mass matrix.  See the file where this is done.

The file assembles the Kg and Mg 

Cheers

Terry

[terryhendicott]

Hi

Here is the Prime 6.0 file conversion.

Cheers

Terry

[Fred_Kohlhepp]

Very nicely done!  (Will run in Express!)

[Fred_Kohlhepp]

Attached is a document I developed a while ago, a spring/mass problem--same math.  Maybe it'll help.

[DM_9837618]

Thanks for your Help. Cheers