# A Multi-Physics Modeling-Based Vibration Prediction Method for Switched Reluctance Motors
## 4 Experimental Results and Verification
### Implementation of Simulated and Experimental Platforms
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Name** & **Value** & **Name** & **Value** & **Name** & **Value** \\ \hline \hline \begin{tabular}{c} Stator Pole \\ Number \\ \end{tabular} & 12 & \begin{tabular}{c} Rotor Pole \\ Number \\ \end{tabular} & 8 & Coil number & 100 \\ \begin{tabular}{c} Stator outer \\ diameter \\ \end{tabular} & 130 mm & \begin{tabular}{c} Rotor outer \\ diameter \\ \end{tabular} & 77.4 mm & \begin{tabular}{c} Lamination \\ coefficient \\ \end{tabular} & 0.95 \\ \begin{tabular}{c} Stator inner \\ diameter \\ \end{tabular} & 78 mm & \begin{tabular}{c} Rotor inner \\ diameter \\ \end{tabular} & 30 mm & \begin{tabular}{c} Rotor pole arc \\ coefficient \\ \end{tabular} & 0.355 \\ \begin{tabular}{c} Stator yoke \\ height \\ \end{tabular} & 8 mm & \begin{tabular}{c} Winding \\ diameter \\ \end{tabular} & 1.2 mm & \begin{tabular}{c} parallel \\ number \\ \end{tabular} & 2 \\ \begin{tabular}{c} Core length \\ \end{tabular} & 120 mm & \
\begin{tabular}{c} Rotor yoke \\ height \\ \end{tabular} & 7 mm &
\begin{tabular}{c} Stator pole arc \\ coefficient \\ \end{tabular} & 0.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Main dimension parameters of the model. Figure 5: Schematic diagram of the simulation platform. In order to accurately model the structure of the SRM in Figure 1a, the constraints between the components are determined according to their real assembly arrangements. The modeling methods for individual components of the SRM are as follows. The motor frame is fixed to the workbench through bolts, and the actual installation is completed by the constraints of the bolt holes and the frame surface. Considering the end cover and motor frame fixed to each other, they are handled as an integration. The stator is pressed into the casing through a pressing machine and is integrated with the frame. In addition, the stator is fixed to the motor frame. The winding is fixed to the stator slot by insulating sheets, which has a great influence on the stator mode and cannot be ignored. The equivalent effect of the windings is explored by changing the density of the stator material:  
\[\overline{\rho}_{s}=\frac{\rho_{s}V_{s}+\rho_{c}V_{W}}{V_{s}}, \tag{12}\]  
where \(\overline{\rho}_{s}\) is the equivalent stator density, \(\rho_{s}\) is the stator density (the density of silicon steel sheet), \(V_{S}\) is the stator volume, \(\rho_{c}\) is the winding density (copper wire density), and \(V_{W}\) is the winding volume. Due to interference fit, the rotor and shaft are fixed to each other. The shaft is fixed to the inner ring of the bearings and thus it remains stationary between the front and rear end covers. The outer rings of both bearings are bonded to the front and rear end covers, and the friction coefficients between the inner and outer rings are set to be 0.0015. Figure 7a shows the mechanical structure of the SRM and Figure 7b presents its meshing model. In the mechanical module, it not only includes the influence of the stator (containing iron core, winding, slot wedge, insulating material, and motor lead), but also fully considers the influence of rotor(containing rotor shaft and rotor core), end cover, bearing, and other structural components of the motor on the system modal. Meanwhile, the boundary conditions are set as the constraint of the movement and rotation of the base of the machine. Based on the simulation results and experimental data, the material parameters are adjusted to make the mass of the simulation mechanical model consistent with the actual mass of SRM. In addition, the model is tuned many times according to experimental results. Figure 6: Electromagnetic field model: (**a**) structure (**b**) mesh. Figure 7: Three-dimensional structure of SRM and its meshing model: (**a**) mechanical structure of the SRM; (**b**) meshing model of the SRM.