## 3 Results and Discussion  
### Electromagnetic Analysis Results  
The magnetic flux density graphs in the main flow path, additional flow path, and core calculated using [PERSON]'s electromagnetic analysis in ANSYS Electronics Desktop are shown in Figures 18, 19, and 20, respectively. For the magnetic flux density graph of the main flow path and the additional flow path, the value at the center of the flow path was extracted based on the damper cross-sectional view, and for the core, the value was extracted at the center of the piston considering the effective area and length of the piston, which is shown in Figure 18.  
Through the analysis, the following results were obtained. The maximum magnetic flux density of the main flow path was 0.1 T when the current was 0.2 A, but as the current increased to 1.0 A, the magnetic flux density was 0.3 T, and it was found to be evenly distributed over the distances of 9-20 mm and 26-37 mm, which is shown in Figure 19. Since this area is the area between the piston and the flux ring, it was found that the damping force due to magnetic force would be stably generated. On the other hand, the magnetic flux density of the additional flow path was up to 0.005 T when the current was 0.2 A and up to 0.05 T when the current was 1.0 A, which was only 6 to 1/20 th of the main flow path. In addition, it was confirmed that the maximum magnetic flux density was limited to some areas where the magnetic flux density was concentrated due to rapid changes in shape, such as the corners of the piston, such as 10 mm, 23 mm, and 35 mm, and this is shown in Figure 20. This is a result that conforms to the design intention of having the additional flow path generate a larger damping force due to the flow than the damping force due to the magnetic field in order to reduce the initial damping force. In addition, as the current increases, the piston's magnetic flux density increases, but as the current increases, the increase gradually decreases due to saturation of the magnetic circuit. The magnetic saturation phenomenon mainly occurred in the middle of the piston and the center of the coil, at a distance of 10 to 16 mm, and had a magnetic flux density of up to 1.75 T when 1.0 A was applied. However, when the current increases from 0.8 A to 1.0 A, the magnetic flux density increase is 0.1 T, which is half of the increase of 0.2 T when the current increases from 0.6 A to 0.8 A. At this time, the saturated magnetic flux increases at a distance of 16 to 29 mm of the additional flow path. It could be seen by referring to Figure 21 that the leakage occurred in an area of 29 mm. In order to intuitively check the effect of magnetic flux saturation, the magnetic flux density images of the piston, plus ring, and MR fluid are shown in Figure 22.  
Figure 17: Sine wave excitation by velocity. Figure 19: Magnetic flux density of the main orifice. Figure 20: Magnetic flux density of the additional orifice. Figure 18: Lines of magnetic flux density graph. Figure 21: Magnetic flux density of the solenoid core. Figure 22: Magnetic flux density of the MR damper. The following results were obtained through analysis. It was confirmed that when the main flow path had a magnetic flux density of about 0.3 T to 1.0 A, the additional flow path had a small value of about 0.05 T. This is because the additional flow path is designed to generate a larger damping force due to the flow than the damping force due to the magnetic field to reduce the initial damping force. In addition, as the current increased, the magnetic flux density of the flow path increased; however, as the current value increased, the increase gradually decreased owing to the saturation of the magnetic circuit.