1. Assumptions
The numerical analysis of the induction heating process of bevel gear by using the finite element software ANSYS needs to simplify and simulate the practical engineering problems. It is extremely complex to fully consider the influence of workpiece material properties and environment on workpiece induction heating process and carry out numerical simulation. Under the condition of ensuring little impact on the research goal and making full use of the existing hardware and software, this paper makes reasonable assumptions and simplification on the dual frequency induction heating process of bevel gear, so as to achieve the unity of process and efficiency to the greatest extent.
In the numerical simulation of dual frequency induction heating of bevel gear, the following assumptions are made:
(1) The bevel gear density remains unchanged.
(2) In the process of temperature field analysis, the temperature changes of induction coil and air are not considered. According to the induction heating principle and heat transfer knowledge, in the process of dual frequency induction heating of bevel gear, the induction coil will produce Joule heat due to resistance, and there is radiant heat between the induction coil and the bevel gear workpiece, which are not considered in numerical simulation. In this paper, the induction coil is made of red copper material. The resistance of red copper material is very small, so the thermal effect of resistance is very small, and the induction coil is connected with circulating cooling water. However, the induction heating time is very short, and the temperature loss is very small relative to the heat production, so it can be ignored.
2. Technical treatment of key problems
The finite element software ANSYS is used to simulate the dual frequency induction heating process of bevel gear. The finite element software DEFORM is used for tissue field simulation. On the premise of ensuring the accuracy of numerical calculation, the implementation method of finite element calculation is processed as follows.
(1) The bevel gear material is 45 steel, and the thermophysical parameters of 45 steel are different at different temperatures. In the simulation of dual frequency induction heating of bevel gear, the nonlinearity of bevel gear material is considered. Write the physical parameters of the material into the file according to the format specified by the software. In the numerical simulation, the software will read the material parameters according to the command flow program for analysis, and will automatically interpolate as needed.
(2) In the electromagnetic thermal coupling analysis of bevel gear, although the nonlinearity of gear material is defined, the permeability and other parameters required for electromagnetic analysis are unchanged in each cycle of electromagnetic analysis and thermal analysis. If the temperature of the bevel gear rises too high in a cycle analysis, that is, the material properties of the bevel gear change greatly, the analysis will deviate from the reality. In the process of numerical simulation, the error is reduced by increasing the number of cycles, that is, reducing the time interval of each cycle.
(3) In terms of model establishment, because the bevel gear structure is complex, a complete three-dimensional model is established in the Three-dimensional Modeling Software Solidworks, and then imported into ANSYS for simulation analysis. In terms of organization simulation, in order to successfully import the temperature field model obtained by induction heating in ANSYS into DEFORM software, it is necessary to ensure that the mesh model of bevel gear in deform is consistent with that in ANSYS. HyperMesh software is used for model mesh division, and then it is imported into ANSYS and deform software for corresponding analysis. The initial microstructure field of bevel gear quenching simulation will be defined according to the temperature field model finally obtained by induction heating, and the microstructure of the unit higher than the austenitizing temperature will be set as austenitic microstructure.