Research Article
Rotor-System Log-Decrement Identification Using Short-Time Fourier-Transform Filter
Table 2
Results of the estimated forward mode parameters at different noise levels with STFT method.
| Number | = 2 μm | = 5 μm | = 8 μm | Frequency/Hz | Log decrement | Frequency/Hz | Log decrement | Frequency/Hz | Log decrement |
| 1 | 76.82 ± 0.08 | 0.2723 ± 0.0030 | 76.93 ± 0.15 | 0.2450 ± 0.0087 | 76.76 ± 0.33 | 0.2684 ± 0.0127 | 2 | 76.97 ± 0.09 | 0.2732 ± 0.0029 | 76.70 ± 0.14 | 0.2732 ± 0.0058 | 76.66 ± 0.18 | 0.2652 ± 0.0044 | 3 | 76.88 ± 0.17 | 0.2658 ± 0.0030 | 76.64 ± 0.31 | 0.2574 ± 0.0106 | 76.79 ± 0.19 | 0.2527 ± 0.0069 | 4 | 76.94 ± 0.06 | 0.2655 ± 0.0032 | 77.01 ± 0.20 | 0.2561 ± 0.0040 | 77.01 ± 0.24 | 0.2451 ± 0.0039 | 5 | 76.86 ± 0.11 | 0.2624 ± 0.0067 | 77.00 ± 0.19 | 0.2762 ± 0.0058 | 77.03 ± 0.14 | 0.2548 ± 0.0049 | 6 | 76.87 ± 0.12 | 0.2607 ± 0.0029 | 76.87 ± 0.20 | 0.2638 ± 0.0049 | 77.11 ± 0.09 | 0.2814 ± 0.0022 | 7 | 76.91 ± 0.07 | 0.2623 ± 0.0017 | 76.77 ± 0.16 | 0.2771 ± 0.0073 | 77.20 ± 0.19 | 0.2961 ± 0.0080 | 8 | 76.98 ± 0.07 | 0.2695 ± 0.0021 | 76.90 ± 0.19 | 0.2656 ± 0.0067 | 76.70 ± 0.30 | 0.3130 ± 0.0512 | 9 | 76.84 ± 0.06 | 0.2567 ± 0.0028 | 77.09 ± 0.15 | 0.2505 ± 0.0038 | 76.76 ± 0.26 | 0.2866 ± 0.0110 | 10 | 76.89 ± 0.08 | 0.2670 ± 0.0044 | 76.95 ± 0.12 | 0.2500 ± 0.0028 | 76.58 ± 0.15 | 0.2705 ± 0.0091 |
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Note: we set the center frequency to 75 Hz; = 41 Hz, = 50 Hz, = 100 Hz, and = 109 Hz.
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