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DM_98376181-Visitor
1-Visitor
March 1, 2021
Question

Structural Dynamics and Stability

  • March 1, 2021
  • 3 replies
  • 3539 views

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?

DM_9837618_0-1614557918088.pngDM_9837618_1-1614557928687.pngDM_9837618_2-1614557935119.png

 

 

 

 

 

 

 

3 replies

T
21-Topaz II
terryhendicott21-Topaz II
21-Topaz II
March 1, 2021

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

    T
    21-Topaz II
    terryhendicott21-Topaz II
    21-Topaz II
    March 1, 2021

    Hi

    Here is the Prime 6.0 file conversion.

    Cheers

    Terry

      F
      Fred_Kohlhepp23-Emerald I
      23-Emerald I
      March 1, 2021

      Very nicely done!  (Will run in Express!)

      F
      Fred_Kohlhepp23-Emerald I
      23-Emerald I
      March 1, 2021

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

        D
        DM_98376181-VisitorAuthor
        1-Visitor
        March 7, 2021

        Thanks for your Help. Cheers

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