HW3: Magentic Mechanic¶
Description¶
Consider an axi-symmetric model of a coil and a plate as depicted in the figure.
The inner and outer radii of the coil, r_1 = 0.0025 m and r_2 = 0.0075 m.
The length of the coil, l_1 = 0.008 m.
The plate thickness and air gap is l_2 = 5 \cdot 10^{-4} m respectively l_3 = 7.5 \cdot 10^{-4} m.
The point C is located in the center of the coil, the point P in the middle of the plate at z = 0.005 m.
The plate is either made from iron or aluminum, with electric conductivity and linear magnetic permeability given in the mat.xml
.
The coil has 40 turns and is fed by a controlled current of i = 10 kA.
Tasks¶
- Create a regular hexaedral mesh using Trelis. (1 Points)
- Create input-xml files for the required CFS++ simulations. (1 Points)
- Document your results by answering the questions below. (13 Points)
Hints¶
- Use the provided templates
coil_transient.xml
,mat.xml
andHW5_template.ipynb
. - Adapt the Trelis input
geometry.jou
. - Use the static simulation to check the prescribed current and boundary conditions.
- Use a time resolution of 20 steps per period.
- Pole force can be neglected.
Submission¶
Submit all your input files (*.jou
, *.xml
) as well as a concise PDF report of your results. Name the archive according to the format HWn_eNNNNNNN_Lastname.zip
.
Mesh Size¶
Estimate the skin depth for both materials. What element size do you suggest? Motivate your suggestion! (3 Points)
Static Analysis¶
Compute the static solution of the coupled magnetic-mechanical problem.
- Plot the vector field of the magnetic flux density. (2 Points)
- Compare the cases for iron and aluminum plate. (2 Points)
- What is the difference? (3 Points)
- Are there displacements? Why / Why not? (3 Points)
Transient Analysis¶
Set up a transient analysis with a sinusoidal coil current with a frequency of 100 Hz and solve the coupled magnetic-mechanical problem. Compute the solution for 4 periods of the coil current.
- Plot the time signal of the z-displacements of point P for both plate-materials in one figure
- Plot the displacement of the plate (paraview warp by vector) for both plate-materials.
- Describe the time signals: Are there transient effects? What is the difference between the amplitudes with aluminum and iron plate and why is there a difference?
You can download the templates linked on this page individually by right click --> save target as. Alternativey, head over to the git repository and use the download button on the top right: Here is a direct link to the zip archive.