Mechanical mass-spring-damper model from IV curve

1. Oct 11, 2006

hey guys, I have an IV cure from which i need to develop a mass-spring damper model..... can somebody help me with that.

the curve has basically a 3 slopee, each linear.....

if somebody has any kinda idea abt this, i can post the curve as an image...

thanks

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Last edited: Oct 11, 2006
2. Oct 11, 2006

Staff: Mentor

I'm not real clear yet on what you are trying to do, but yes, any figures or more info that you can post will help.

3. Oct 11, 2006

i have posted a curve that i have obtained from tests on a bunch of nanowires....... i need to develop a spring-mass-damper system that best describes this curve....

the mechanical analogy for current i guess is Force and for voltage is Velocity, so this same curve is again a force vs velocity curve..... so is it possbile to get a spring-mass-damper system from the curve?

4. Oct 11, 2006

Staff: Mentor

I'm still not clear on the mechanical analogy thing, but before that, why is that plot not linear? How was that data gathered?

5. Oct 11, 2006

i guess the plot is not completely linear because this is how the nanowires behave..... the data was gathered using a Keithley 4200, which is a semiconductor characterization system and a probe station

6. Oct 11, 2006

Staff: Mentor

Fair enough. Why do you need to translate that into a spring paradim, or am I misinterpreting your question?

7. Oct 11, 2006

this is basically part of my research...... nobody has researched the materials i have been working on..... so now that we have some data and plots, we want to get an electrical model and also into a spring paradime... we want to investigate certain efeects that might be going on in the wires..... like maybe a peizo electric effect.... so that is why i need to develop those models

8. Oct 12, 2006

waht

The intristic parameter you can recover from IV curve is R (resistance), which is simply V/I

The instristic parameter of a spring is of course the spring constant k.

Hooke's law is F = -k*x

so k = -F/x

Now you can substitute Volts (V) for Force (F) and current (I) for displacement (x)

That would model a non-linear spring, possible made from some weird alloys, because your data is non-linear.

BTW, this is one of many possible transformations. Whatever you do, you have to preserve R.