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Recent content by Patkin

  1. Patkin

    Why can not two modes coincide perfectly for some cases in Flutter phenomena?

    Hi dear friends, I have a question about flutter phenomena. As you know, flutter occurs when two modes ( for example first mode and second mode ) coincide ( I mean after a specific velocity, the frequencies of two modes, will be the same and equal) and the damping term will change into positive...
  2. Patkin

    Piezoelectric Ceramic (PZT) material withstand the stress due to the applied maximum voltage?

    Hi friends, I am working on piezoelectric patch and I have a question. I want to know if piezoelectric ceramic (PZT) material withstand the stress due to the applied maximum voltage. How is it possible to calculate it ?! What are the relations ? Thank you in advance.
  3. Patkin

    Piezoelectric Ceramic (PZT) material withstand the stress due to the applied maximum voltage?

    Hi friends, I am working on piezoelectric patch and I have a question. I want to know if piezoelectric ceramic (PZT) material withstand the stress due to the applied maximum voltage. How is it possible to calculate it ?! What are the relations ? Thank you in advance.
  4. Patkin

    How to plot Mode shapes of a structure using its frequencies

    Thank you all for your great help. I want to know how it is possible to plot the mode shapes ( a static display of a mode shape ) using Complex Eigen vectors ?! Assume that these are my Eigenvavlues : Landa1= 5+2i Landa2=5-2i and corresponding Eigenvectors are : V1=[1 1-2i]T V2=[1 1+2i]T
  5. Patkin

    How to plot Mode shapes of a structure using its frequencies

    My structure is a continuous simply supported beam. I have problem with calculating its mode shapes using eigenvectors !! I mean I don't know how to use eigenvectors or eigenvalues to calculate mode shapes of a n-DOF ( n Degree Of Freedom ) system!! ( Here, my problem is a 6 DOF system! ) Does...
  6. Patkin

    How to plot Mode shapes of a structure using its frequencies

    Dear friends, I am a beginner in the mechanical vibration field. I have the EOM ( Equation Of Motion ) of my problem in the standard form ( Mxtt+Cxt+Kx=0).Then, in the next stage, I uesd State-space form ( AXt+BX=0 ) of my EOM to calculate the eigenvalues of the system in order to extract the...
  7. Patkin

    Multilayer Sandwich structures

    Hello Friends, I want to derive the vibration formulation of a sandwich beam with 7 layers using Hamilton principle. I have already searched on the internet for any possible book or paper, but I couldn't find anything useful. Could you please help and tell me a website, book, paper or...
  8. Patkin

    Modeling non-Newtonian viscosity in MSC.PATRAN

    Hi guys, I want to model non-Newtonian viscosity in MSC.PATRAN !! I have some points relating to my viscosity function. Does anyone know how it is possible to model it in MSC.PATRAN ??!! Thank you in advance.
  9. Patkin

    Modeling non-Newtonian viscosity in NASTRAN

    Hi Dear friends, I want to model non-Newtonian viscosity in NASTRAN !! I have some points relating to my viscosity function. Does anyone know how it is possible to model it in NASTRAN ??!! Thank you in advance. [smarty]
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