Top 12 Vibration Metrics to Monitor
& How to Calculate Them
Top 12 Vibration Metrics Webinar Recording
What are the Top 12 Vibration Metrics to Monitor?
- Acceleration Peak
- Acceleration RMS
- Crest Factor
- Standard Deviation of Acceleration
- Velocity RMS
- Displacement RMS
- Peak Frequency
- Acceleration RMS below 65 Hz
- Acceleration RMS from 65 to 300 Hz
- Acceleration RMS above 300 Hz
- Peak Pseudo Velocity
- Frequency of Peak Pseudo Velocity
For a detailed analysis and example of each metric, please see Steve's blog post: Top 12 Vibration Metrics to Monitor & How to Calculate Them
Easy Metrics
Data Set | Acceleration Peak (g) | Acceleration RMS (g) | Crest Factor | Standard Deviation (g) |
---|---|---|---|---|
Fault_021 | 1.038 | 0.199 | 5.222 | 0.198 |
Fault_014 | 1.339 | 0.158 | 8.484 | 0.158 |
Fault_007 | 0.650 | 0.121 | 5.361 | 0.121 |
Normal | 0.269 | 0.066 | 4.081 | 0.065 |
Peak is Peaky | Clear Trend with RMS | RMS & Std Dev |
Sine Wave Table
Data Set | Acceleration Peak (g) | Acceleration RMS (g) | Crest Factor | Standard Deviation (g) |
---|---|---|---|---|
100 Hz, 0g Bias | 1.000 | 0.705 | 1.418 | 0.707 |
29 Hz, 0g Bias | 0.999 | 0.701 | 1.424 | 0.707 |
29 Hz, 1g Bias | 1.999 | 1.221 | 1.636 | 0.707 |
15 Hz, 0g Bias | 0.995 | 0.696 | 1.430 | 0.707 |
Look at Standard Deviation! |
Velocity and Displacement from PSD
Vel From PSD (in/s) | Vel From Time (in/s) | Disp From PSD (in) | Disp From Time (in) | Vel Error % | Disp Error % | |
---|---|---|---|---|---|---|
Fault_021 | 0.0086 | 0.0080 | 0.000054 | 0.000054 | 7.8 | -0.5 |
Fault_014 | 0.0090 | 0.0084 | 0.000007 | 0.000010 | 7.2 | -26.3 |
Fault_007 | 0.0069 | 0.0067 | 0.000010 | 0.000011 | 3.7 | -5.3 |
Normal | 0.0272 | 0.0264 | 0.000087 | 0.000083 | 3.2 | 4.8 |
Integrate to Velocity Easily | Good Agreement with Calculations in Time Domain |
Summary of All Metrics
High Frequency RMS is Best | Specifically High Frequency | Just 1 Example - Different Per Application |
Conclusion
- Go Get Some Data!
- Summarize into Quantifiable Metrics
- Monitor Over Time