In this paper, ANSYS software is used to dynamically simulate the dual frequency induction heating process of bevel gear, involving electromagnetic field analysis and temperature field analysis. Different units are used in different field analysis. When selecting the elements for numerical simulation, it is necessary to fully consider the coupling analysis method, model dimension, physical field type, load type, boundary conditions and so on. In this paper, the sequential coupled physical file method is used to analyze the three-dimensional finite element analysis of the dual frequency induction heating process of bevel gear.
When selecting the type of electromagnetic field analysis unit, due to the existence of ferromagnetic region, 3D edge element method is selected. The selected unit should support harmonic analysis and can apply current density load. After the electromagnetic field analysis and solution, you need to check the results of magnetic field intensity, magnetic induction intensity, Joule heat, current density and so on. Therefore, the unit needs to have degrees of freedom including vector magnetic potential AZ and volt to output these results. Based on the above requirements, the 6-sided solid element solid117 element with 20 node element is adopted. During the finite element analysis, it is also necessary to set the unit degrees of freedom according to the unit materials, set the bevel gear unit degrees of freedom generated by induced eddy current to volt and AZ degrees of freedom, and set the induction coil and air unit degrees of freedom to AZ degrees of freedom.
| Material Science | Unit selection | Material properties | Unit selection | Material properties |
| 45 steel | SOLID117 | Relative permeability Resistivity | SOLID90 | Thermal conductivity (KXX) Specific heat capacity (c) |
| Copper | SOLID117 | Relative permeability Resistivity | Null | — |
| Air | SOLID117 | Relative permeability Resistivity | Null | — |
In order to maintain the consistency of the grid model, the selection of temperature field analysis element should consider the number of nodes of the element selected in the previous electromagnetic field analysis. Therefore, the element also needs to be a 20 node hexahedral solid element. The thermal analysis in the process of induction heating is transient thermal analysis, which needs to apply the heating generation rate as the heat source load. Considering comprehensively, solid90 element is used for transient thermal analysis, and solid90 element has temp degrees of freedom. Because only the induction heating effect of bevel gear is considered, the grid elements of air and induction coil are not involved in the calculation when analyzing the temperature field, so the grid elements of air and induction coil are set as null elements. The table shows the specific settings of unit selection of different materials.