[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

# Re: [femm] Why femm sometimes never finised the calculation ?

- To: femm@yahoogroups.com
- Subject: Re: [femm] Why femm sometimes never finised the calculation ?
- From: David Meeker <dmeeker@foster-miller.com>
- Date: Thu, 06 Dec 2001 13:46:54 -0500
- Organization: Foster-Miller, Inc.
- References: <9uo8ej+9eh8@eGroups.com>

    matthewc_98 wrote:

    > Hi All,
    >
    > I have used femm ver. 3.1 for one month. I would like to
    > thank Dave, because this is a great sofware. There is one question
    > needed to have your advice. I used femm to simulate the solenoids.
    > In some types of solenoids, it works very well, but in other types
    > of solenoids, it never ending the calculation.Even I used different
    > mesh densities; it still didn't work. Can you help me to answer this
    > question? Thank you so much.
    >
    > Best Regards,
    >
    > Matthew

    Hmm--it's hard to say what's going on without seeing an example.

    Sometimes bad things can happen if you have very small angles between lines
    in your mesh (or a line tangent to a circle, for example)--triangle, the
    meshing program, can break down in that case, or make a mesh that causes
    things to hang. If this is the case, try redrawing the problem region in a
    way that avoids the sharp angles.

    It is also might be possible to make a nonlinear material that has
    convergence problems--this might happen in some materials with a really
    pronounced "initial permeability" region. The solver can then end up
    bouncing around that section of the curve, never finishing the Newton
    Iteration part of the solution. You can try substituting linear materials to
    see if this is the problem. If so, you might have to "smooth out" the
    initial permeability region to get things to converge.

    Dave.

    begin:vcard
    n:Meeker;David
    tel;fax:781-890-3489
    tel;work:781-684-4070
    x-mozilla-html:TRUE
    url:http://members.aol.com/_ht_a/dcm3c
    org:Foster-Miller, Inc.;Electrical and Electronic Systems Group
    version:2.1
    email;internet:dmeeker@foster-miller.com
    title:Senior Engineer
    adr;quoted-printable:;;350 Second Avenue=0D=0A;Waltham;MA;02451-1196;USA
    fn:David Meeker, Ph.D.
    end:vcard

- Follow-Ups:
  - Re: Why femm sometimes never finised the calculation ?
    - From: "matthewc_98" <matthewc_98@yahoo.com>

- References:
  - Why femm sometimes never finised the calculation ?
    - From: "matthewc_98" <matthewc_98@yahoo.com>

- Prev by Date: Why femm sometimes never finised the calculation ?
- Next by Date: Incorrect Field values returned by FEMM
- Previous by thread: Why femm sometimes never finised the calculation ?
- Next by thread: Re: Why femm sometimes never finised the calculation ?
- Index(es):
  - Date
  - Thread