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Imaginary part of velocity
Posted 2 févr. 2017, 06:56 UTC−5 2 Replies
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Hi,
I am trying to probe velocity of a specific domain in frequency domain piezoelectric model. In the model I defined a voltage difference along the piezo material. Geometry is a little bit complex which consist piezo actuators and metal structure around it. In order to understand resonance frequencies of the structure, I probe the boundary of the tip of structure to find velocity vs freq. However when I computed the velocity, it shows imaginary velocity values. I couldn't figured what that means. Is it be reasonable to assuming that absolute of these values are actual velocities?
Thanks in advance
I am trying to probe velocity of a specific domain in frequency domain piezoelectric model. In the model I defined a voltage difference along the piezo material. Geometry is a little bit complex which consist piezo actuators and metal structure around it. In order to understand resonance frequencies of the structure, I probe the boundary of the tip of structure to find velocity vs freq. However when I computed the velocity, it shows imaginary velocity values. I couldn't figured what that means. Is it be reasonable to assuming that absolute of these values are actual velocities?
Thanks in advance
2 Replies Last Post 2 févr. 2017, 11:25 UTC−5
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Posted:
8 years ago
Frequency domain analysis is a steady state sinusoidal analysis, where all quantities are assumed to vary sinusoidally at the same frequency. The analysis yields you the phasor (a complex quantity with units) for all calculated variables. A nonzero imaginary part for a variable indicates that the variable has a phase shift with respect to the driving voltage.
For example, for the velocity vx the magnitude is abs(vs) and phase arg(vx).
DWGreve
DWGreve Consulting
For example, for the velocity vx the magnitude is abs(vs) and phase arg(vx).
DWGreve
DWGreve Consulting
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Posted:
8 years ago
Thank you for great answer that helps me a lot. Also I was wonder why the impedance (1/es.Y11) does not have same resonance frequency with maximum displacement velocity's frequency. Is it safe to assume for a structure to have resonance frequency which maximum displacement and displacement velocity occur?