This chapter discusses the use of the Direct method for surface forces
(dFmagS) to create force collections in the Import / Export data
context: this kind of collection allows to compute forces on a face mesh
with the forces density dFmagS.
The following topics are covered in this page:
Description of the approach
Creation of this force collection
Limitations
Example
Description of the approach
This approach evaluates a force density on a face support (Flux mesh or imported
mesh) at the interface between two regions with different magnetic permeability
defined with a data support as shown in
Figure 1. The
magnetic force density dFmagS is
directly computed on the support and then is integrated with different methods to get the
most adapted distribution for mechanics-coupled simulations. Being this approach
only able to compute the normal forces to the mesh of the support, tangential and
axial forces are not taken into account.Figure 1. Simple actuator with a yoke, a coil and a plate with a support described
by a line and then extruded with the help of data supports.
Creation of this collection
This approach (and so this kind of collection) is available in all Flux modules (2D,
3D and Skew) for all the magnetic applications. This collection can be created as
follows:
In the data tree, select the menu Forces data collection
In the dedicated GUI for Forces data collection, choose Direct
method for surface forces (dFmagS)
Choose a data support to collect the data
Choose the collection interval:
Collect for all the steps of the scenario
Collect only for the current step
Collect for a specified interval
Click OK
Right click on the forces data collection just created in the data tree and
run the command Collect data
Note: For AC Steady State applications, the user must also choose the type of
values to collect: continuous, instantaneous (the phase value is asked) or
pulsating values.
Note: In advanced mode, more integration options are
available, see this pagefor more details.
Once the collection is created and the
data collected, forces can be visualized with the Data visualizers and / or exported to OptiStruct
with the Data export function.
Limitations
Only the forces normal to the support can be evaluated
This collection must be defined at the interface between two regions with
different magnetic permeability
Example
In this example, the aim is to compute the global force on the plate of the actuator
shown in Figure 1.
To do this, we define a support to collect the data: it comes from the Flux mesh and
is the same as the one described in Figure 1; it has been
created from the line that we choose to extrude during the creation of the
support.
Once the collection is correctly defined, the data must be collected by right click
and Collect data on the forces data collection; now forces can be visualized
with the Data visualizers as shown in the figure
below:Figure 2. Distribution of nodal forces in Newton on the actuator plate.
The analysis of global forces may be achieved with several approaches:
The approach described on this page
With Computation on physical entity available in the tab
Computation > On physical entity
Table 1. Comparison of the results between the global computation in the Import /
Export data context and the global computation on the region with the
computation on physical entity.
