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  1. gopi9

    Relation between mass, stiffness and Damping

    I have seen in many examples that mass is low, damping is close to mass values but slightly higher than mass values and stiffness is very high when compared with both mass and damping. Can any one justify this? One more thing I found in many examples is that they are using all the stiffness and...
  2. gopi9

    Relation between mass, stiffness and Damping

    Thanks everyone. I want to know how the parameters vary for a bridge. Thanks elogesh
  3. gopi9

    Relation between mass, stiffness and Damping

    Hi, Will there be any relationship between Mass, Damping and Stiffness. I want to use a 5 node example and I don't know what values should I use for mass, stiffness and damping.
  4. gopi9

    relationship between natural frequency obtained from continuous and discrete models

    I have one more question... can we compare damped natural frequency with the undamped natural frequency.Is there any relationship between them.
  5. gopi9

    relationship between natural frequency obtained from continuous and discrete models

    Thank you so much....I already figured the problem myself..
  6. gopi9

    relationship between natural frequency obtained from continuous and discrete models

    Hi, I know how to extract the natural frequencies from continuous and discrete model by using eigen-value equations. This is the continuous model Mx..+Cx.+Kx=F (x. is differentiation of x). The eigenvalue equation for this is (K-1/ω2 M)u=0, 1/ω2 represents frequency. If we convert that...
  7. gopi9

    relationship between natural frequency obtained from continuous and discrete models

    Hi, I know how to extract the natural frequencies from continuous and discrete model by using eigen-value equations. This is the continuous model Mx..+Cx.+Kx=F (x. is differentiation of x). The eigenvalue equation for this is (K-1/ω2 M)u=0, 1/ω2 represents frequency. If we convert that...
  8. gopi9

    Natural frequency extraction

    Thank you so much Greg. I figured out the solution for that. I got the values which matches with the required frequencies. The code is shown below Time=6500; Y1_1=Y2(:,1); N=length(Y1_1); k=0:N-1; T=N/Time; freq=k/T; X=fft(Y1_1); plot(freq,abs(X)); The only problem is the rate that is 6500. I...
  9. gopi9

    Natural frequency extraction

    ok thanks. I can do that. But am i going in a correct way to get natural frequency from impulse response.
  10. gopi9

    Natural frequency extraction

    Thank you so much Greg. Should i take f=1/t; and plot(f,fft2). Are you suggesting that this might help. I tried this Greg. That did not help.
  11. gopi9

    Natural frequency extraction

    This is my code. nat1 there represents natural frequency. Does peak value of magnitude FRF represents natural frequency. Thanks.http://files.engineering.com/getfile.aspx?folder=a6e4a305-0c16-4d2e-8e3c-4166f8ca5c27&file=New_Text_Document.txt
  12. gopi9

    Natural frequency extraction

    I did not get you. What do u meant by bin number? Do u mean the left most side of the figure? The left most side of the figure represents the natural frequency. I got those values by theoretical analysis. I have verified those values too, they are correct.
  13. gopi9

    Natural frequency extraction

    Thanks for the reply. yes i am working in matlab. I used an example and created 2nd order system. The transfer function is for that 2nd order system. I got the impulse response for that system. I used FFT to convert it in to FRF. I have attached the file for the response that I got with the FRF...
  14. gopi9

    Natural frequency extraction

    Hi everyone. I have the impulse response output of a 2nd order system. What I did was got the frequency response from the transfer function(2nd order equation) and the peaks of the frequency response represents the natural frequency and I found that the natural frequency from these response are...

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