## 3 Results and Discussion
### Flow Analysis Results
This is illustrated in Figure 26.  
It was confirmed that when the diameter of the orifice is large, the damping force changes rapidly at low piston speeds, but it can produce a fast-damping effect, and when the diameter is small, the opposite effect can be produced, as shown in the Figure 26. Based on the results, the total damping force is compared when \(D_{\mathit{office}}=1.0\) mm, \(D_{\mathit{office}}=1.2\) mm, and \(D_{\mathit{office}}=1.1\) mm, as shown in Figure 27. The comparison is based on an applied current of 1.0 A, which is the most severe change in the damping force and is a basic characteristic of the MR damper. It is difficult to infer the most appropriate diameter of the additional flow path based on the results shown in Figure 26, because the advantages and disadvantages of each case are clear. Therefore, the most appropriate diameter of the additional flow path is selected through the average attenuation coefficient in the previously set range of \(-0.4\) m/s \(\leq\)\(V_{\mathit{piston}}\)\(\leq\) 0.4 m/s. Table 9 confirms that the average attenuation coefficient of \(D_{\mathit{office}}=1.1\) mm had the highest value of 1949 N-s/m. Therefore, in this model, the final attenuation coefficient (Table 10) based on the current is calculated as follows. Figure 27: Comparison of variable \(D_{\mathit{orifice}}\). Figure 31: Displacement when the vehicle velocity was 60 km/h. Figure 30: Acceleration when the vehicle velocity was 30 km/h. Figure 29: Velocity when the vehicle velocity was 30 km/h. Figure 34: Displacement when the vehicle velocity was 90 km/h. Figure 33: Acceleration when the vehicle velocity was 60 km/h. Figure 26.0 Velocity when the vehicle velocity was 60 km/h. For a displacement of 30 km/h, when the added current was 0 A, 0.6 A, and 1 A, the maximum values were 0.015 m, 0.014 m, and 0.0136 m, and the times to reach them were 0.414 s, 0.399 s, and 0.394 s, respectively. For the test vehicle, the maximum values and reaching times were 0.0138 m and 0.395 s, respectively. Concerning speed, when the added current was 0 A, 0.6 A, and 1 A, the maximum values were 0.0844 m/s, 0.0769 m/s, and 0.0754 m/s, and the times to reach them were 1.15 s, 1.20 s, and 1.21 s, respectively. For the test vehicle, the maximum values and reaching times were 0.0759 m/s and 1.21 s, respectively. For acceleration, when the added current was 0 A, 0.6 A, and 1 A, the maximum values were 0.622 m/s2, 0.485 m/s2, and 0.451 m/s2, and the time to reach them was 0.871 s, 0.884 s, and 0.892 s, respectively. For the test vehicle, the maximum values and reaching times were 0.462 m/s2 and 0.889 s, respectively. For a displacement of 60 km/h, when the added current was 0 A, 0.6 A, and 1 A, the maximum values were 0.0124 m, 0.0119 m, and 0.0117 m, and the time to reach them was 0.287 s, 0.269 s, and 0.262 s, respectively. For the test vehicle, the maximum values and reaching times were 0.0118 m and 0.265 s, respectively. When the added current was 0 A, 0.6 A, and 1 A, the maximum values of speed were 0.219 m/s, 0.184 m/s, and 0.175 m/s, and the time to reach them was 0.766 s, 0.74 s, and  
Figure 26.1 Velocity when the vehicle velocity was 90 km/h. Figure 26.2 Acceleration when the vehicle velocity was 60 km/h. 0.7305 s, respectively. For the test vehicle, the maximum values and reaching times were 0.178 m/s and 0.7335 s, respectively. Concerning acceleration, when the added current was 0 A, 0.6 A, and 1 A, the maximum values were 1.97 m/s2, 1.73 m/s2, and 1.66 m/s2, and the time to reach them was 0.621 s, 0.5935 s, and 0.584 s, respectively. For the test vehicle, the maximum values and reaching times were 1.69 m/s2 and 0.5875 s, respectively. It was confirmed that when the vehicle speed was 30 km/h and 60 km/h, the higher the added current, the smaller the maximum value and the shorter the time to reach it. For a displacement of 90 km/h, when the added current was 0 A, 0.6 A, and 1 A, the maximum values were 0.00608 m, 0.00672 m, and 0.00708 m, and the time to reach them was 0.676 s, 0.6445 s, and 0.6335 s, respectively.