Design and Engineering Forum 
[Home] [Design Resources] 
[ POSTING POLICY / RULES ][Archive#1] [Archive #2] [Archive #3] [Calculators] 

designing a vibration absorber...  
Post Reply  Forum 
Posted by: misty2 ^{®} 05/07/2004, 12:39:08 Author Profile Mail author Edit 

Post Reply  Recommend  Alert  Rate  View All   Next  
Replies to this message 
Re: designing a vibration absorber...  
Re: designing a vibration absorber...  misty2  Post Reply  Top of thread  Forum 
Posted by: jbel ^{®} 05/22/2004, 07:55:34 Author Profile Mail author Edit 
First, I believe you have formulated an incorrect matrix. I am assuming the following conditions: k1 = spring from ground to machine k2 = spring from machine to absorber c1 = dashpot from ground to machine c2 = dashpot from machine to absorber My equations of motion: m1x1" = k1x1 k2(x1  x2)  c1x1 c2(x1x2) m2x2" = k2(x2  x1)  c2(x2x1) These are the same as your equations!!!!!!! Try this matrix form: [m1 0] [x1"]+ [c1+c2 c2][x1’]+ [k1+k2 k2][x1] =[Fosinwt] [0 m2] [x2"] [c2 c2][x2’] [k2 k2] [x2] [ 0 ] Review your equations and redo your matricies and you should get the same answer, I think you just transposed something when writing the stiffness matrix. As far as calculating k2: Do just as you said. set (omega) = (omega)(nat. abs.) noting that (omega)(nat. abs.) = sqrt(k2/m2) Then: (omega)^2 = (k2/m2) Now, choose m2 to be some value, and if you know (omega) you then know k2!!!!!! This allows you to choose your absorbing mass and then calculate the corresponding spring stiffness. 
Post Reply  Recommend  Alert  Rate  Where am I? Original Top of thread 
Powered by Engineers Edge
© Copyright 2000  2019, by Engineers Edge, LLC All rights reserved. Disclaimer