welcome to this video demonstration. This video shows how the solver NX Magnetics
for Simcenter can be used to
simulate engineering problems with
electromagnetic mechanical coupling. The NX Magnetics solver is an add-on
product to Siemens Simcenter 3D. It is
developed, supported and delivered by Dr. Binde Engineers, a solution partner of
Siemens.
I want to show two examples, both containing the same physical effect. One
example is more academic, the other more
realistic in practice. Both examples deal
with electric wires being affected by
magnetic fields, so Lorentz forces will
appear and act on the wire. We are
interested in the mechanical behavior of
the wire, deformation stresses and
reaction forces of the conductor due to
Lorentz forces. So we solve the
electromagnetic solution first to
find the Lord's forces, then do a
mechanical elasticity solution to find
deformations stresses and reaction
forces. All this is done either
completely integrated in the Magnetics
solver or by a coupling of NX
Magnetics with NX Nastran.
First see the first more academic example the wire
is placed between two permanent magnets. We do a static simulation just to see
the effect of Lorentz forces acting on
the wire. The model is ready to solve. It
comes from the training material of
NX Magnetics. Let's solve. This only
takes some seconds. And it has finished.
Alternatively to using the Magnetics
internal elasticity solver we can also
use NX Nastran for the elasticity
part of the solution. In post-processing
we first check the magnetic field.
This magnetic field is mainly coming
from the two permanent magnets. Of course
the wire creates a rotating magnetic
field
additionally. Let's now see the Lorentz
forces being produced and finally let's
see the deformation and stresses in the
wire. Now let's go to the more realistic
example. It is a circuit breaker for low
voltage conditions. Again there is a wire,
now more massive and modeled as a coil.
In this case there are no permanent
magnets but there is a magnetic field
produced by the electric current itself.
This field now also creates Lorentz
forces on the wire. We simulate the
short-circuit case so the electric
current increases very fast in a short
time period.
The current definition is therefore now
given by an analytical law containing
sinus and exponential forms. We have
applied two times the usual value in the
simulation, just to see more effect.
So the solution now is a transient
one with 30 time steps. Solve if time will
be about one hour
on a desktop computer. Here we see the
definition of the elasticity solver
being coupled to the electromagnetic
solution. It is set to transient and we
want to use the electromagnetic forces
in the elasticity solution. Let's see the
requested results. We see the current in
the wire as a plot result. Of course we
are also interested in the behavior of
the current over time. So we see all
tabular results are available here in
the navigator. The current result is this
one and we see that the current
increases in a short time period and it
goes up to 510 mA. Next let's see eddy
currents. They are of interest for
further computations of losses. Here are
the eddy current results. Let's plot them.
And we see that the most important one
is the one on the coil and
this one produces a maximum of about
1000 watts. Let's see the magnetic flux
density as a plot result. This result is
good for validation purposes. See how the
wire produces a rotating field. This
field can also be used to check for EMC,
electromagnetic compatibility, for the
shielding effect of the housing. Next we
see the force acting on the plunger. We
also want to see the force behavior over
time.
So let's plot these three curves and we
find that the maximum force is the z
direction and it has a value of about 8
Newtons.
Finally let's see the deformation and
stress results in the coil as an
animation. Also we want to see the
maximum values of deformation over time.
So we see the maximum deformation is the one in the z direction again and it
has a value of about one point three
millimeters. Many other results are
available like magnetic forces and
reaction forces or torques. In further
simulations we can also ask for
temperatures or the plunger motion.
Many thanks for watching this video
demonstration. If you have questions
please contact the Simcenter experts at
Dr. Binde Engineers.
