## 3 Numerical Simulations and Discussion
### Application of Adjustment Point
#### 3.3.1 Results of the First Kind of Simulation
For the cross-coupled coefficients, the identified values are almost equal to zero (the setting value) and the identification errors of the cross-coupled stiffness coefficients are higher than those of the cross-coupled damping coefficients. The maximum absolute values of k1.xy, k2.xy,..., k8.xy are only 0.0945, 0.416, 0.465, 0.477, 1.51, 0.320, 0.213 and 0.0108, respectively. The maximum absolute values of c1.xy, c2.xy,..., c8.xy are only 0.0210, 0.0520, 0.135, 0.0987, 0.888, 0.143, 0.0941 and 0.00331, respectively. The maximum absolute values of k1.yx, k2.yx,..., k8.yx are only 0.135, 0.566, 0.864, 0.408, 3.20, 0.492, 0.162 and 0.0137, respectively. The maximum absolute values of the identified c1.yx, c2.yx,..., c8.yx are only 0.00298, 0.126, 0.0164, 0.120, 0.381, 0.143, 0.138 and 0.000972, respectively. Similar results can be obtained according to Tables 15 and 16, which show the simulation results of g1.4 and g1.1. Using the rotor h4.4 supported by oil-journal bearings, the maximum relative errors of each bearing's main and cross-coupled coefficients are obtained in Figure 6. The nodes, where the bearings and discs are located, are used as the m + n measuring points in these simulations. The adjustment points in Table 2 are used. According to Figure 6, for the main coefficients, the maximum relative errors of k1.xx, k2.xx,..., k8.xx are almost equal to zero. They are only 0.444%, 0.0148%, 0.673%, 0.000898%, 0.00119%, 0.000141%, 0.00634% and 0.0591%, respectively. The maximum relative errors of c1.xx, c2.xx,..., c8.xx are smaller than those of the stiffness coefficients. They are 0.00337%, 0.000564%, 0.0264%, 4.98 \(\times\) 10\({}^{-5}\)%, 2.40 \(\times\) 10\({}^{-5}\)%, 1.27 \(\times\) 10\({}^{-5}\)%, 0.000214% and 0.000497%, respectively, and are quite small. In the y direction, the maximum relative errors of k1.yy, k2.yy,..., k8.yy are only 0.346%, 0.0199%, 1.63%, 0.00436%, 0.00494%, 0.000453%, 0.00912% and 0.628%, respectively. The maximum relative errors of the identified c1.yy, c2.yy,..., c8.yy, which are only 0.00490%, 0.000540%, 0.0288%, 1.91 \(\times\) 10\({}^{-5}\)%, 1.34 \(\times\) 10\({}^{-5}\)%, 2.90 \(\times\) 10\({}^{-5}\)%, 7.93 \(\times\) 10\({}^{-5}\)% and 5.57 \(\times\) 10\({}^{-5}\)%, respectively, are smaller than that of the stiffness coefficients. For the cross-coupled coefficients, the identification errors are almost equal to zero and the identification errors of the cross-coupled stiffness coefficients are higher than those of the cross-coupled damping coefficients. The maximum relative errors of k1.xy, k2.xy,..., k8.xy are only 1.23%, 0.0931%, 0.282%, 0.0114%, 0.00580%, 0.000826%, 0.00455% and 0.0668%, respectively. The maximum relative errors of c1.xy, c2.xy,..., c8.xy are only 0.0634%, 0.000508%, 0.0334%, 3.39 \(\times\) 10\({}^{-5}\)%, 3.71 \(\times\) 10\({}^{-5}\)%, 3.28 \(\times\) 10\({}^{-5}\)%, 0.000267% and 0.00464%, respectively. The maximum relative errors of k1.yx and k2.yx,..., k8.yx are 0.514%, 0.0107%, 1.53%, 0.00121%, 0.00267%, 0.000671%, 0.00461% and 0.0852%, respectively. The maximum relative errors of c1.yx and c2.yx,..., c8.yx are only 0.0209%, 0.000460%, 0.0324%, 1.43 \(\times\) 10\({}^{-5}\)%, 7.89 \(\times\) 10\({}^{-6}\)%, 6.56 \(\times\) 10\({}^{-5}\)%, 0.000196% and 0.00237%, respectively. Similar results can be obtained according to Tables 17 and 18, which show the simulations results of h1.4 and h1.1.