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Validation Case: TEAM 20

The TEAM 20 validation case belongs to electromagnetics. This test case aims to validate the following parameters:

  • BH magnetic permeability curve
  • Open coils
  • Forces and torques result control

SimScale’s simulation results were compared to measured data presented by Nakata et al.\(^1\) and further expanded in TEAM Workshop 3\(^2\).

Geometry

A solenoid with a steel core and plunger pole is analyzed using the magnetostatics module in SimScale. In this project, a current applied to the coil generates a force onto the pole, which is monitored in the results.

The image below shows the complete assembly (on the left) and the quarter solenoid model used as reference in this validation project (on the right):

team 20 validation case geometry electromagnetics
Figure 1: TEAM 20 solenoid geometry, consisting of a copper coil (in dark grey), a steel pole (in blue), and a steel yoke (in light grey)

Besides the three solid parts, an additional air domain is created around the solenoid, resulting in the following geometry:

solenoid geometry validation case emag
Figure 2: Final geometry used in the present validation case

Analysis Type and Mesh

Analysis Type: Electromagnetics

Model: Magnetostatics

Mesh and Element Types: The meshes from this validation case were created in SimScale with the Standard meshing algorithm.

Find below an overview of the meshes used in this validation study:

MeshMesh TypeNodesElement Type
Coarse MeshStandard917653D tetrahedral
Moderate MeshStandard7977803D tetrahedral
Fine MeshStandard20761593D tetrahedral
Table 1: Standard mesh metrics. The meshes consist exclusively of tetrahedral elements

Figure 3 shows the fine mesh aspect on the surfaces of the solenoid:

solenoid mesh electromagnetics
Figure 3: Standard mesh with fineness 10 and volumetric refinements

Simulation Setup

Material:

  • Air: flow region
    • Material behavior: Soft magnetic
    • \((σ)\) Electric conductivity: 0 \(S/m\)
    • Magnetic permeability type: Constant
    • \((μ_r)\) Relative magnetic permeability: 1
  • Copper: coil
    • Material behavior: Soft magnetic
    • \((σ)\) Electric conductivity: 5.7e7 \(S/m\)
    • Magnetic permeability type: Constant
    • \((μ_r)\) Relative magnetic permeability: 1
  • Steel: pole and yoke
    • Material behavior: Soft magnetic
    • \((σ)\) Electric conductivity: 6.99e6 \(S/m\)
    • Magnetic permeability type: BH curve, available below for download and also in Team Problem 20\(^3\)

Coils:

The TEAM 20 validation case involves coils with 1000, 3000, 4500, and 5000 ampere-turns.

Since a quarter model is used, the setup involves an open coil with the following settings:

  • Coil type: Stranded
  • Number of turns: 1000
  • Wire diameter: 0.001 \(m\)
  • Excitation: Current
  • \((I)\) Current: a parametric definition with 4 currents of interest: 1, 3, 4.5, and 5 \(A\)
open stranded coil validation case
Figure 4: Open, stranded coil with 4 currents defined via a parametric setup.

Boundary Conditions:

All external faces receive a magnetic flux tangential boundary condition.

boundary condition emag validation
Figure 5: Boundary condition configuration for the present validation case.

Reference Solution

Initial experimental results for forces in the Z-direction on the steel pole were presented by Nakata et al.\(^1\) and further expanded in TEAM Workshop 3\(^2\). When considering the full CAD model, the reference solution is:

Ampere-turns\(F_z\) on the steel pole \([N]\)
10008.1
300054.4
450075.0
500080.1
Table 2: Reference results for forces in the z-direction for each case

Result Comparison

A mesh sensitivity study was performed with a set of three meshes: a coarse mesh with 91765 nodes, a moderate mesh with 797780 nodes, and a fine mesh with 2076159 nodes.

Since the validation case uses a quarter model, the forces in the Z direction from the simulation were multiplied by 4 and then compared against the reference results.

mesh sensitivity study solenoid emag validation
Figure 6: Compilation of the mesh sensitivity study results.

For all four studies, the results between the moderate and fine mesh shifted less than 0.15%, indicating great stability at these mesh densities.

Table 3 compares the experimental data against the fine mesh results:

Ampere-turnsExperimental \(F_z\) \([N]\)Fine Mesh \(F_z\) \([N]\)Error [%]
10008.18.88.7
300054.455.92.7
450075.075.60.8
500080.180.70.8
Table 3: TEAM 20 experimental data versus fine mesh results

The simulation results showed good correspondence with the reference data, also highlighting the importance of a mesh sensitivity study in gaining understanding and confidence in simulation results.

References

  • T. Nakata, N. Takahashi, H. Morishige, J. L. Coulomb, and J. C. Sabonnadiere, “Analysis of 3-d static force problem,” in Proceedings of TEAM Workshop on Computation of Applied Electromagnetics in Materials, pp. 73-79, 1993.
  • T. Nakata, N. Takahashi, M. Nakano, H. Morishige, and K. Masubara, “Improvement of measurement of 3-d static force problem (problem 20),” in Proceedings of TEAM Workshop , Miami, November 1993.
  • “TEAM Problem 20. 3-D Static Force Problem”

Last updated: August 11th, 2025

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