## 3 Results
### Influence of Integral Squeeze Film Bearing Damper on Vibration Control  
When there is an unbalanced mass at the cantilevered disk, the unbalanced single-side cantilevered rotor system will strongly vibrate through the first order critical speed, and the amplitude will increase sharply, which will cause the rotor system to fail, resulting in a dangerous operation process. Through the Section 2.3, the time domain and frequency domain diagrams of the four working conditions of the rotor system were simulated, which can help us predict the vibration control effect in advance. Therefore, it is believed that installing of an integral squeeze film bearing damper at the bearing housing will effectively reduce the amplitude of the unbalanced single-side cantilevered rotor system. We explored the vibration control on the rotor system by changing the installation position and quantity of integral squeeze film bearing dampers. An unbalanced mass of 0.15 g\(\cdot\)m was applied to the cantilevered disk as an excitation. As can be seen from Figure 13, the vibration amplitude of the rotor system was the largest at the critical speed. The time domain spectrum acquired at 2600 r/min (close to the critical speed) was analyzed for the four different working conditions, as shown in Figure 14 and Table 3.  
It can be seen from the above graph and table that the theoretical results were basically consistent with the experimental results and the maximum experimental vibration peak-to-peak values at  
Figure 14: Vibration control of ISFBD in time domain spectrum: (**a**) theoretical results; (**b**) experimental results. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Working Condition** & **Experimental P-P** & **Theoretical P-P** \\  & **Amplitude (\(\mu\)m)** & **Amplitude (\(\mu\)m)** \\ \hline Two rigid supports (working condition 1) & 1885.57 & 1844.60 \\ ISFBD installed away from cantilevered end (working condition 2) & 1826.08 & 1790.44 \\ ISFBD installed near cantilevered end (working condition 3) & 1500.71 & 1494.76 \\ Two ISFBDs (working condition 4) & 1233.42 & 1213.96 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Vibration control under different working conditions in time domain spectrum. 2600 r/min were as follows: working condition 1, 1885.57 \(\upmu\)m; working condition 2, 1826.08 \(\upmu\)m; working condition 3, 1500.71 \(\upmu\)m; and working condition 4, 1233.42 \(\upmu\)m.  
Based on working condition 1, the vibration of working conditions 2, 3 and 4 decreased by 3.16%, 20.41%, and 34.59%, respectively. It can be known that if only one integral squeeze film bearing damper is installed, it has a better damping effect when it is installed near the cantilevered end. If two integral squeeze film bearing dampers are installed, they can have a good vibration control effect, which is the best outcome among the four working conditions. The time domain spectrum of 2600 r/min as shown in Figure 14 by Fourier transform to obtain the frequency domain spectrum. We still compare the theoretical results with the experimental results in the frequency domain spectrum, and the simulation results were well fitted with the actual experimental results. The damping effect of integral squeeze film bearing damper at 1 \(\times\) frequency, 2 \(\times\) frequency, 3 \(\times\) frequency, and other multiple frequencies was explored, as shown in Figure 15 and Table 4.  
It can be seen from the experimental results in the above diagram and table that if only one integral squeeze film bearing damper is installed, the 1 \(\times\), 2 \(\times\), and 3 \(\times\) frequencies have a damping effect. Also, an integral squeeze film bearing damper installed near the cantilevered end has a better effect by up to 21.19%, 41.73%, and 30.97%, respectively. If two integral squeeze film bearing dampers are installed, the 1 \(\times\), 2 \(\times\), and 3 \(\times\) frequencies have good damping effects that are improved by up to 33.67%, 60.57%, and 50.26%, respectively.