Release 11.0 Documentation for ANSYS
www.kxcad.net Home > CAE Index > ANSYS Index > Release 11.0 Documentation for ANSYS
This section describes a 2-D static magnetic analysis of a solenoid actuator by choosing items from the ANSYS GUI menus. See Doing an Example 2-D Static Magnetic Analysis (Command Method), which explains how to perform the same example analysis by issuing ANSYS commands, either manually during a session or in batch mode.
The example analysis, based on a solenoid actuator, analyzes the actuator as a 2-D axisymmetric model. The example calculates the force on the armature (the moving component of the actuator) and the inductance of the coil. Figure 2.8: "Diagram of a Solenoid Actuator" below shows you the solenoid actuator:
The analysis uses the parameters listed below to model the actuator geometry:
| Parameter | Description |
|---|---|
| n=650 | Number of turns in the coil; used in postprocessing |
| I=1.0 | Current per turn |
| ta=.75 | Thickness of inner leg of magnetic circuit |
| tb=.75 | Thickness of lower leg of magnetic circuit |
| tc=.50 | Thickness of outer leg of magnetic circuit |
| td=.75 | Armature thickness |
| wc=1 | Width of coil |
| hc=2 | Height of coil |
| gap=.25 | Gap |
| space=.25 | Space around coil |
| ws=wc+2*space | |
| hs=hc+.75 | |
| w=ta+ws+tc | Total width of model |
| hb=tb+hs | |
| h=hb+gap+td | Total height of model |
| acoil=wc*hc | Coil area |
| jdens=n*i/acoil | Current density of coil |
The magnetic flux that the coil current produces is assumed to be small enough that no saturation of the iron occurs. This allows a single iteration linear analysis. To simplify the example model, the flux leakage out of the iron at the perimeter of the model is assumed to be minimal. Under normal conditions, the model would include air surrounding the iron to model the effects of flux leakage.
Because no leakage is assumed at the perimeter of the model, the flux flows parallel to the surface. You enforce this by placing a "flux parallel" condition around the model.
For a static (DC) current, you may enter the current in the form of current density over the area of the coil. The ANSYS APDL is used to compute the current density from the number of turns, the current per turn, and the coil area. The armature is flagged for a force calculation.
In postprocessing, the forces are summarized for the armature, using both a Maxwell stress tensor and a virtual work calculation. Flux density also is displayed. The final postprocessing operation computes the terminal parameters including coil inductance.
The example analysis is only one of many possible 2-D static magnetic analyses. Not all such analyses follow exactly the same steps or perform those steps in the same sequence. The properties of the material or materials being analyzed and the conditions surrounding those materials determine which steps a specific analysis needs to include.
For a detailed step-by-step procedure for the magnetic analysis of a solenoid actuator, see the Electromagnetics Tutorial.
