Re: why different force??

["David Meeker" <dmeeker@xxxxxxxx>]

--- In femm@xxxxxxxxxxxxxxx, "ahmad_m_eid" <ahmad_m_eid@xxxx> wrote:
> Dear all 
> I use femm in my work in linear generator
> when I trace a path around the stator to find the force by "force
> from stress tensor" I get a value for the force on stator
> 
> when I use the block integration and select all stator blocks anf find
> force from " force via weighted stress tensor" I get another value and
> away from the first value comes from line integral.
> 
> what is the best way to find the force on stator?
> 
> how can one explain these different results?

The accuracy of the stress tensor line integral can be quite sensitive
to the choice of contour and the mesh density. I did the "force via
weighted stress tensor" block integral in an attempt to make things
less sensitive. You could view what the weighted stress tensor does
as automatically picking a "good" set of contours to take the integral
along. 

That being said, it is also often a good idea to re-run an analysis
with an increased mesh density to see how well the force result has
converged.

Dave.
--
http://femm.berlios.de/dmeeker