Release 11.0 Documentation for ANSYS
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This section describes how to do a 2-D transient magnetic analysis of a solenoid actuator by choosing items from the ANSYS GUI menus. Doing an Example Transient Analysis (Command Method) explains how to perform the same example analysis by issuing ANSYS commands, either manually during a session or in batch mode.
The 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), inductance of the coil, and the coil current in response to a voltage excitation. Figure 4.2: "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 |
| 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 |
The solenoid actuator model for this transient example is identical to the solenoid example described in "2-D Static Magnetic Analysis". Instead of a DC current excitation, the coil is supplied a voltage excitation which varies over time.
The coil is supplied a voltage which ramps from 0 volts to 12 volts over a .01 second time frame. After that, the voltage is held constant and the analysis runs until a time of .06 seconds. The coil requires additional characterization, including cross-section area and fill factor. Resistivity for copper is also provided. The armature is assumed to be solid steel, so it requires the input of electrical resistivity as well.
The purpose of the example analysis is to track the coil current, armature force, and coil inductance over time in response to the applied voltage excitation. (The coil inductance will change slightly due to the eddy currents developed in the armature.)
The solution uses constant time stepping over three load steps ending at .01, .03, and .06 seconds respectively. In the time-history postprocessor (POST26), the desired results are computed for the defined element components using the PMGTRAN command or equivalent GUI menu options. You can review the results graphically using the DISPLAY program from the filemg_trns.plt created by the PMGTRAN command.
In this step, you specify a title for the example analysis and set analysis preferences.
Enter the ANSYS program. To do so, use the procedures described in the Operations Guide.
Choose Utility Menu> File> Change Title. The Change Title dialog box appears.
Enter the title 2-D Solenoid Actuator Transient Analysis.
Click on OK.
Choose Main Menu> Preferences. The Preferences for GUI Filtering dialog box appears.
Click the "Magnetic-Nodal" option on.
Click on OK.
This example uses the preferred higher-order element PLANE53.
Choose Main Menu> Preprocessor> Element Type> Add/Edit/Delete. The Element Types dialog box appears.
Click on Add. The Library of Element Types dialog box appears.
In the scrollable fields, click on (highlight) Magnetic Vector and Vect Quad 8nod53 (PLANE53). Then, check that the element type reference number is set to 1 (default).
Click on Apply. The Element Types dialog box now lists element type 1. In the Library of Element Types dialog box, the PLANE53 element remains selected but the element type reference number will change to 2. (If the element type reference number does not change automatically, set it to 2.)
Click on OK. The Element Types dialog box now lists element type 2 (also PLANE53).
With element type 1 selected, click on Options. The PLANE53 Element Type Options dialog box appears.
Change the "Element Behavior" field to axisymmetric.
Click on OK. ANSYS returns you to the Element Types dialog box.
With element type 2 selected, click on Options. The PLANE53 Element Type Options dialog box appears.
Change the "Element Behavior" field to axisymmetric.
Change the "Element degree(s) of freedom" field to "AZ CURR."
Click on OK.
In the Elements Types dialog box, click Close.
The material properties for the example analysis are assumed to be linear; they are magnetic permeability of air, iron, coil and armature. (Typically, you specify iron as a nonlinear B-H curve.) The air elements are material 1, material 2 is the iron elements, material 3 represents the coil elements, and material 4 is the armature elements.
Choose Main Menu> Preprocessor> Material Props> Material Models. The Define Material Model Behavior dialog box appears.
In the Material Models Available window, double-click on the following options: Electromagnetics, Relative Permeability, Constant. A dialog box appears.
Enter 1 for MURX (Relative permeability) and click on OK. Material Model Number 1 appears in the Material Models Defined window on the left.
Choose menu path Material> New Model, then enter 2 for the Material ID. Click on OK. Material Model Number 2 appears in the Material Models Defined window on the left.
In the Material Models Available window, double-click on Constant again. Another dialog box appears.
Enter 1000 for MURX (Relative permeability), and click on OK.
Choose menu path Edit> Copy. Choose 1 for from Material number, and enter 3 for to Material number. Click on OK. Material Model Number 3 appears in the Material Models Defined window on the left.
In the Material Models Defined window, click on Material Model Number 3 to highlight it.
In the Material Models Available window, double-click on the following options: Resistivity, Constant. A dialog box appears.
Enter 3e-8 for RSVX (Electrical resistivity), and click on OK.
Choose menu path Edit> Copy. Choose 3 for from Material number, and enter 4 for to Material number. Click on OK. Material Model Number 4 appears in the Material Models Defined window on the left.
In the Material Models Defined window, double-click on Material Model Number 4, and Permeability (constant). A dialog box appears and includes the data specified for this material.
Replace the MURX (Relative permeability) field with 2000, and click on OK.
In the Material Models Defined window, under Material Model Number 4, double-click on Resistivity (constant). A dialog box appears and includes the data specified for this material.
Replace the RSVX field (Electrical resistivity) with 70e-8, and click on OK.
Choose menu path Material> Exit to remove the Define Material Model Behavior dialog box.
Use of parameters enables you to rerun the analysis from the log file with new parameter values. For convenience, the example enters the solenoid dimensions in centimeters. However, before solving the model, you must scale the geometry to meters because the MKS system of units is required.
Choose Utility Menu> Parameters> Scalar Parameters. The Scalar Parameters dialog box appears.
Type in the parameter values listed below. After typing each value, press the ENTER key. If you make a mistake while entering a parameter, just retype it before you press ENTER. To erase an incorrect parameter after you have entered it, click on it and then click on Delete.
| Parameter | Description |
|---|---|
| n = 650 | Number of coil turns |
| 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 |
Review the parameter values you entered, then click on Close. (If you did not end each parameter definition by pressing ENTER, you can click on Accept instead.)
Click SAVE_DB on the ANSYS Toolbar.
In this step, you define four real constants for the coil.
Choose Main Menu> Preprocessor> Real Constants> Add/Edit/Delete. The Real Constants dialog box appears.
Click on Add. The Element Type for Real Constants dialog box appears.
Choose element type 2 and click on OK. The Real Constant Set Number 1, for PLANE53 dialog box appears.
Enter the following field values:
"Coil cross-sectional area" (CARE) field: enter acoil*(0.01**2)
"Total number of coil turns" (TURN) field: enter n (recall that n = 650)
"Current in z-direction" (DIRZ) field: enter 1
"Coil fill factor" (FILL) field: enter .95
Click on OK. The Real Constants dialog box now lists constant set 1.
Click on Close in the Real Constants dialog box.
You create the example model by overlapping six rectangles. You can create a rectangle either by entering its dimensions in a dialog box or by picking points on the working plane. (This example uses the "create by dimensions" method.)
Choose Main Menu> Preprocessor> Modeling> Create> Areas> Rectangle> By Dimensions. The Create Rectangle By Dimensions dialog box appears.
Enter the following values in the appropriate fields. You can use the Tab key to move from field to field.
X1 field: enter 0
X2 field: enter w
Y1 field: enter 0
Y2 field: enter tb
Click on OK.
Choose Utility Menu> PlotCtrls> Numbering. The Plot Numbering Controls dialog box appears.
Click "Area Numbers" to on.
Click on OK.
Choose Utility Menu> Plot> Areas.
To create the second rectangle, repeat steps 1 and 2. In place of the input values for step 2, enter these:
X1 field: enter 0
X2 field: enter w
Y1 field: enter tb
Y2 field: enter hb
Click on Apply.
To create the third rectangle, enter these values:
X1 field: enter ta
X2 field: enter ta+ws
Y1 field: enter 0
Y2 field: enter h
Click on Apply.
Create the fourth rectangle by entering these values:
X1 field: enter ta+space
X2 field: enter ta+space+wc
Y1 field: enter tb+space
Y2 field: enter tb+space+hc
Click on OK.
Choose Utility Menu> Plot> Replot.
Click SAVE_DB on the ANSYS Toolbar.
In this step, a Boolean overlap operation creates new areas at all intersections of the four rectangles and remaining areas.
Choose Main Menu> Preprocessor> Modeling> Operate> Booleans> Overlap> Areas. The Overlap Areas picking menu appears.
Click on Pick All. The display of areas refreshes automatically.
Click on SAVE_DB in the ANSYS Toolbar.
Choose Main Menu> Preprocessor> Modeling> Create> Areas> Rectangle> By Dimensions. The Create Rectangle By Dimensions dialog box appears.
Create the fifth area by entering the following values:
X1 field: enter 0
X2 field: enter w
Y1 field: enter 0
Y2 field: enter hb+gap
Click on Apply.
Create the sixth area by entering the values shown below:
X1 field: enter 0
X2 field: enter w
Y1 field: enter 0
Y2 field: enter h
Click on OK.
Choose Main Menu> Preprocessor> Modeling> Operate> Booleans> Overlap> Areas. The Overlap Areas picking menu appears.
Click on Pick All. The display of areas refreshes automatically.
Choose Main Menu> Preprocessor> Numbering Ctrls> Compress Numbers. The Compress Numbers dialog box appears.
Switch “Nodes” to “All” in the Label field. Click on OK.
Choose Utility Menu> Plot> Replot. The new display shows the compressed area number set.
Click on SAVE_DB in the Toolbar.
In this step, you assign attributes first to the coil area, then to the armature, and finally to the iron areas.
Choose Main Menu> Preprocessor> Meshing> Mesh Attributes> Picked Areas. The Area Attributes picking menu appears.
Click on the coil area (Area 2), then click on OK in the picking menu. The Area Attributes dialog box appears.
In the "Material number" drop down menu, set the number to 3.
Set the "Element type number" drop down menu to 2.
Click on Apply. You return to the picking menu.
Click the Box button on.
Press and drag the left mouse button to draw a box around Areas 1,12, and 13.
Click on OK in the picking menu. The Area Attributes dialog box reappears.
Change the material number to 4.
Change the element type number to 1.
Click on Apply.
Click on areas 3, 4, 5, 7, and 8, then click on OK in the picking menu. The Area Attributes dialog box reappears.
Change the material number to 2 and click on OK.
Choose Main Menu> PlotCtrls> Numbering. The Plot Numbering Controls dialog box appears.
Click the "Elem/Attrib numbering" button to "Material numbers," then click on OK.
Click on the SAVE_DB button in the Toolbar.
In this step, you use the smart meshing feature of ANSYS to specify a uniform (moderately fine) mesh for your model.
Choose Main Menu> Preprocessor> Meshing> MeshTool. The MeshTool appears.
Turn SmartSizing on and move the SmartSize slider to 4.
Choose Areas, Quad, and Free. Then click on MESH. The Mesh Areas picking menu appears.
Click on Pick All. The display changes to show the meshed areas.
Click Close on the MeshTool.
Choose Utility Menu> Select> Entities. The Select Entities dialog box appears.
Change the "entities to pick" button from Nodes to Elements, and check that the selection method is set to By Num/Pick.
Click on OK. The Select Elements picking menu appears.
Click the Box picking button on.
In the Graphics Window, press and drag the left mouse button to draw a box around the armature, making sure to select only elements in the armature!
In the picking menu, click on OK.
Choose Utility Menu> Select> Comp/Assembly> Create Component. The Create Component dialog box appears.
In the "Component name" field, enter arm.
Change the "Component is made of" field to Elements.
Click on OK.
Choose Utility Menu> Select> Everything.
Choose Main Menu> Preprocessor> Loads> Define Loads> Apply> Magnetic> Flag> Comp. Force/Torq. The Apply Magnetic Force Boundary Conditions dialog box appears.
The name arm will appear in the "Component name" field. Click on the name, and then click on OK. A window appears, notifying you that force boundary conditions have been applied. Read the window contents and then click on Close.
Choose Utility Menu> Select> Entities. The Select Entities dialog box appears.
Set the "entities to be picked" button to Elements and the picking method button to By Num/Pick.
Click on OK. The Select Elements picking menu appears.
Click the Box picking button on.
Press and drag the left mouse button to draw a box around the coil elements.
Click on OK.
Choose Utility Menu> Select> Entities. The Select Entities dialog box appears.
Change the "entities to be picked" button to Nodes and the picking method button to By Num/Pick. Click OK. The Select Nodes picking menu appears.
Click the Box picking button on.
Press and drag the left mouse button to draw a box around the coil nodes.
Click on OK.
Choose Main Menu> Preprocessor> Coupling/Ceqn> Couple DOFs. The Define Coupled DOFs picking menu appears.
Click the Box picking button on. Press and drag the left mouse button to draw a box around the coil nodes.
Click on OK. The Define Coupled DOFs dialog box appears.
Type 1 in the "Set reference number" field.
Set the "Degree-of-freedom label" field to CURR.
Click on OK.
Choose Utility Menu> Select> Comp/Assembly> Create Component. The Create Component dialog box appears.
In the "Component name" field, type coil.
Change the "Component is made of" field to Elements. Click OK.
Choose Utility Menu> Select> Everything.
Choose Main Menu> Preprocessor> Modeling> Operate> Scale> Areas. The Scale Areas picking menu appears.
Click on Pick All. The Scale Areas dialog box appears.
In the fields for RX, RY, and RZ scale factors, enter .01, .01, and 1 respectively.
Leave the "Items to be scaled" field set on Areas and Mesh, but change "Existing areas will be" to Moved.
Click on OK.
Choose Main Menu> Solution> Analysis Type> New Analysis. The New Analysis dialog box appears.
Click the Transient button on and click on OK.
When the Transient Analysis dialog box appears, click OK to accept the default of Full.
Choose Utility Menu> Select> Entities. The Select Entities dialog box appears.
Set the "entities to be picked" button to Nodes and the picking method button to Exterior.
Click on OK.
Choose Main Menu> Solution> Define Loads> Apply> Magnetic> Boundary> Flux Par'l> On Nodes. The Apply Flux-Parallel Condition on Nodes picking menu appears.
Click on Pick All.
Choose Utility Menu> Select> Comp/Assembly> Select Comp/Assembly. The Select Component or Assembly dialog box appears.
In the "Select entities belonging to Component or Assembly" field, click on COIL.
Click on OK.
Choose Main Menu> Solution> Define Loads> Apply> Magnetic> Excitation> Voltage Drop> On Elements. The Apply VLTG on Elems picking menu appears.
Click on Pick All. The Apply VLTG on Elems dialog box appears.
In the "Voltage drop mag." (VLTG) field, enter 12.
Click on OK.
Choose Utility Menu> Select> Everything.
Choose Main Menu> Solution> Load Step Opts> Time/Frequenc> Time and Substps. The Time and Substep Options dialog box appears.
In the "Time at end of load step" field, enter .01. Click on OK.
Choose Main Menu> Solution> Load Step Opts> Time/Frequenc> Time - Time Step. The Time and Time Step Options dialog box appears.
In the "Time step size" field, enter .002. Click on OK.
Choose Main Menu> Solution> Load Step Opts> Output Ctrls> DB/Results File. The Controls for Database and Results File Writing dialog box appears.
If the "Item to be controlled" field is not set to All Items, set it to that value.
In the "File write frequency" field, click "Every substep" on.
Click on OK.
Choose Main Menu> Solution> Solve> Current LS. Review the information in the /STATUS window; then click on Close to close it. Click OK in the Solve Current Load Step dialog box to start the solution. Click Close when you receive the Solution is done message.
Choose Main Menu> Solution> Load Step Opts> Time/Frequenc> Time and Substps. The Time and Substep Options dialog box appears.
In the "Time at end of load step" field, enter .03. Click on OK.
Choose Main Menu> Solution> Solve> Current LS. Review the information in the /STATUS window; then click on Close to close it. Click OK in the Solve Current Load Step dialog box to start the solution. Click Close when you receive the Solution is done message.
Choose Main Menu> Solution> Load Step Opts> Time/Frequenc> Time - Time Step. The Time and Time Step Options dialog box appears.
In the "Time step size" field, enter .005. Click on OK.
Choose Main Menu> Solution> Load Step Opts> Time/Frequenc> Time and Substps. The Time and Substep Options dialog box appears.
In the "Time at end of load step" field, enter .06. Click on OK.
Choose Main Menu> Solution> Solve> Current LS. Review the information in the /STATUS window; then click on Close to close it. Click OK in the Solve Current Load Step dialog box to start the solution. Click Close when you receive the Solution is done message.
In this part of the example, the ANSYS program calculates and summarizes armature force, coil current, and coil inductance.
Choose Main Menu> TimeHist Postpro> Elec&Mag> Magnetics.
Specify arm as the element component for force calculation.
Specify coil as the element component for current and inductance.
Click on OK. The ANSYS program calculates and summarizes the results data you selected, then brings up a window displaying the information. It may take a few minutes for the window to appear.
Review the results summaries, then click on Close.
To leave the ANSYS program, do the following:
Click on Quit in the Toolbar. The Exit from ANSYS dialog box appears.
Choose "Quit - No Save!"
Click on OK.
