NTNUJAVA Virtual Physics Laboratory
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Misc => Physics related resources => Topic started by: afpedraza on April 22, 2011, 06:35:59 am



Title: Duffing oscilator
Post by: afpedraza on April 22, 2011, 06:35:59 am
We are  Andres Fernando Pedraza, and Malory Johana Sanchez From Bogotá. Colombia, we want show a simulation of chaos in duffing oscilator. thanks

(http://www.phy.ntnu.edu.tw/home/andres/Escritorio/Duffing.jpg)


Title: Re: Duffing oscilator
Post by: Fu-Kwun Hwang on April 22, 2011, 08:21:43 am
You will find "Upload new EJS jar file." check box, at the same line where you find "submit" button when you edit message.

Click the check box, then select the EJS jar file from your computer (the same file you have attached in the previous message).
Then click the submit (Post) button, and you will find simulation displayed as part of forum message.

You can update the jar file,too!( when you edit the message)
Please try it.  ;D


Title: Re: Duffing oscilator
Post by: afpedraza on April 22, 2011, 09:38:25 am
Thanks professor Fun. We hope that it can display the simulation, please let us know if it was possible to see

Very very thanks


Title: Re: Duffing oscilator
Post by: Fu-Kwun Hwang on April 22, 2011, 04:23:12 pm
You need to upload the jar file according to the process I have described in my previous message to be able to show the simulation as part of forum message.

I will do it for you now. The simulation will be displayed follow this line.



Title: Re: Duffing oscilator
Post by: Fu-Kwun Hwang on April 22, 2011, 04:29:52 pm
I know the problem why it was not working for you now.
You have changed the filename for the jar file created by EJS.

The original jar file was ejs_elastico.jar

It will work for you if you upload the original jar file generated from EJS.
I am eager to find more simulation created by you and your group members.  ;D


Title: Re: Duffing oscilator
Post by: lookang on April 22, 2011, 08:04:59 pm
nice one Andres Fernando Pedraza, and Malory Johana Sanchez From Bogotá. Colombia!

just like to say the facebook fan page connected more people using Ejs to come here
http://www.facebook.com/pages/Easy-Java-Simulation-Official/132622246810575


this duffing oscillator is cool
i read on
and found another cool applets to understand the Ejs version one by  afpedraza
http://www.math.udel.edu/~hsiao/m302/JavaTools/osduffng.html
http://www.peter-junglas.de/fh/physbeans/applets/duffingoscillator.html
http://www.scholarpedia.org/article/Duffing_oscillator they look like this (http://www.scholarpedia.org/wiki/images/thumb/e/e5/Duffing-MagnetelasticBeam.gif/212px-Duffing-MagnetelasticBeam.gif)
Duffing oscillator is an example of a periodically forced oscillator with a nonlinear elasticity, written as
 (http://www.scholarpedia.org/wiki/images/math/d/e/c/dec8d87618e1acdcb45b70ea44786b31.png)(1),
where the damping constant obeys , and it is also known as a simple model which yields chaos, as well as van der Pol oscillator.

from http://dynlab.mpe.nus.edu.sg/mpelsb/me4213/Duffing.html
Duffing oscillator, a 2 degree of freedom oscillator with cubic stiffness.
x’’ + ax’ + x3 – x = b cos(t)
The oscillator can exhibit chaotic (i.e. irregular) oscillations


Question:
how come the applet is 2 mass oscillating so what is the difference between the red and blue mass?
i open the evolution page and study
dv/dt = -k1*x/m*s*(b*x*x-1)-R/m*v+A*Math.cos(w*t)
dv1/dt = -k1*x1/m*s*(b*x1*x1-1)-R/m*v1+A*Math.cos(w*t)

is it to show despite the same equation and same initial conditions, the red and blue mass ends up differently to show chaos?


Title: Re: Duffing oscilator
Post by: afpedraza on April 23, 2011, 01:16:56 am
red and blue masses have different initial conditions but very close to each other, we want to show how two initially nearby trajectories can be separated into the future.

XoRED=1.50m
XoBLUE=1.51m


Title: Re: Duffing oscilator
Post by: lookang on April 23, 2011, 09:00:29 pm
ic...thx!


Title: Re: Duffing oscilator
Post by: ahmedelshfie on May 04, 2011, 06:02:39 pm
Well, is a nice applet i was busy last days ago so didn't have chance to watch it good work Andres Fernando Pedraza, and Malory Johana Sanchez From Bogotá. Colombia
I llike the simulation.


Title: Re: Duffing oscilator
Post by: desertrose3 on January 18, 2012, 06:05:54 am
I see the simulation. Thanks again. ALways informational!