Summary

Gap elements are an effective way to approximate insulation gaps in conductors and air gaps in magnetic circuits. However, prior to EMSolution r8.4, there were some limitations: gap surfaces could not intersect, and they could not be applied to triangular or tetrahedral element meshes. With the addition of new functionality in r8.5, these limitations have been removed. Here is an example of the calculation.

Explanation

Fig. 1 shows the mesh model. In the figure, a square plate (1/8 model) is divided by gap faces. The external magnetic field is assumed to be uniform in the z direction. The boundary conditions are $B_n$=0 in the x=0 and y=0 planes. Generally, the current flows perpendicular to the $B_n$=0 plane, but by defining the gap plane as the $B_n$=0 plane, as shown in the figure, we can eliminate the crossing current.

In addition, intersecting gap faces can now be defined, as sown in Fig. 1. Figs. 2 and 3 show the eddy current density distribution when calculated with a hexahedral element mesh. The insulation gap is simulated successfully. Figs. 4 and 5 show the results using triangular prism elements. The results are almost identical to the hexahedral case. Tetrahedral meshes can be used in the same way. When using gap elements, the following points should be noted

• As before, the gap face must be defined by extending one layer outward from the conductor or magnetic material. However, it is not necessary to extend outward from the symmetry plane.
• Gap elements on symmetry surfaces and periodic boundary surfaces should be defined with the model mesh side as the positive direction.
• Gap faces that cross periodic boundary planes cannot be handled. Gap elements on periodic boundaries can be used.

Fig.1 Division of square plate by insulation gaps

Fig.2 Eddy Current Distribution (Hexahedral element, real part)

Fig.3 Eddy Current Distribution (Hexahedral element, imaginary part)

Fig.4 Eddy Current Distribution (Triangular prism elements, real part)

Fig.5 Eddy current distribution (Triangular prism elements, imaginary part)

Download

Triangular Pillar Mesh　　Sample Data DL

・ input
・ pre_geom2D.neu
・ 2D_to_3D

Hexahedral Mesh　　Sample Data DLサンプルデータDL

・ input
・ pre_geom2D.neu
・ 2D_to_3D