[Getdp] Calculation the mechnical force between magnets.

[Bernhard Kubicek]

In my last .pro, I (hopefully) used the integral over the whole _area_
of E=int dArea*mu^(-1)*0.5*B(r)^2.
I neglected the factor 0.5.
Honestly, I recommend to forget about batch files, install Cygwin or
MinGW and use bash scripting in Windows.
You will have so much more possibilities.

Also, I think that the h field inside is not correct in your outputted
pos file.
greetings,
 bernhard

On Wed, 2008-07-23 at 11:07 +0200, Sebastian wrote:

> Dear Bernhard:
> 
> Today I am working in a BATCH file ( MSDOS script 
> file, I am using Gmsh in Windows ) for 
> moving  the magnets ( Geometry ) and obtain data for each step.
> 
> Do you known the FEMM package ?
> http://femm.foster-miller.net/wiki/HomePage
> This is a very interesting Freeware software, for 2D ElectroMagnetic problems.
> 
> In this software the force is calculated by integration
> 
> F=integration((H(B*n)+B(H*n).(H*B)n)/2)
> 
> where n denotes the direction normal to the surface at the point of interest.
> This integration is calculated using the data in 
> a perimeter around the object that you want to 
> find the force. See the FEMM  manual for more 
> details, about integration of Maxwell's Stress 
> Tensor, see page 44. I am sure that may interest you.
> 
> I want to find how to obtain this integration in GetDP.
> 
> In my webpage you can see how I have created a 
> Lua script to move magnets ( geometry ), and 
> rotor generator, and obtaining images and data in each step.
> http://www.tinet.org/~sje/femm/acgen.htm
> 
> Thanks.
> 
> At 10:15 23/07/2008, you wrote:
> >Dear Sebastian,
> >I just played around a bit with your files, and 
> >maybe I have a method that somehow can calculate the force.
> >You create different meshes, where the magnets are varied in position.
> >As an output for each mesh, you calculate the total field energy.
> >the force should then be the variation of the 
> >field energy divided by the dislocation distance.
> >but I have not verified things, only thing is I 
> >wrote an script that does the variation.
> >after the script (that should work with linux 
> >after setting the paths correctly, or with cywin 
> >in windows) you can do the manual calculations to get the force.
> >I _think_ that you just need to add the field 
> >energies of all domains. but what confuses me is 
> >that the magnets have negative energy?? I quite 
> >in a hurry now, and cannot investigate much further right now.
> >nice greetings,
> >bernhard
> >
> >On Tue, 2008-07-22 at 13:45 +0200, Sebastian wrote:
> >>
> >>
> >>Dear friends:
> >>
> >>Here do you have a 2D magnetostatic simulation.
> >>
> >>The question is. How can I obtain the mechanical force in N, produced
> >>by one magnet over the other ?
> >>
> >>Thanks.
> >>
> >>Sebastian Jardi Estadella
> >><mailto:sjardi at telefonica.net>sjardi at telefonica.net
> >>http://www.tinet.org/~sje/index_en.htm
> >>_______________________________________________ 
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> >________________________________________
> >
> >arsenal research
> >
> >Geschäftsfeld MEA /
> >
> >Business MEA
> >
> >DI Bernhard Kubicek
> >
> >Österreichisches Forschungs- und Prüfzentrum Arsenal Ges.m.b.H.
> >FN 165088b; UID-Nr.: ATU 46577208
> >Sitz der Gesellschaft: Wien; Gerichtsstand: Wien
> >
> >Austria, 1210 Wien, Giefinggasse 2
> >
> >ph: +43 (0) 50550-DW, f: +43 (0) 50550-DW
> >
> >mobile: +43 (0)664/ 12 34 567
> >
> ><mailto:bernhard.kubicek at arsenal.ac.at>bernhard.kubicek at arsenal.ac.at
> >
> >www.arsenal.ac.at
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> 
> 
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