A full detailed document is attached with this article along a demonstration model in version 2021.1Summary and ConclusionThis document is addressed to Simcenter 3D Motion users working on system including gears transmission for vibration analysis before eventual acoustic simulation for noise and signature. It includes FFT theory reminders and a practical example workflow comparing waterfall (Campbell) plot results on a demonstration model. The end scope if for identifying critical shaft rotation speeds and the according vibration levels.
This model is a simple transmission with 2 gears on 2 shafts connected via bearings to a housing made flexible. This model is available for download.
Table of content of the PDF document (extract)1. Scope
2. Summary and Conclusion
3. Theory FFT (Reminder)
4. Simcenter 3D Documentation
5. Example Hands-on
5.1 Discrete Sweep 1000-5000 RPM, increment 1000 RPM; Motion solver CPU 1415 sec
Model and Load Pre-processing (FFT) of the Discrete sweep results – CPU 11 sec
5.2 Continuous Sweep 1000-5000 RPM (10,100) Print 0.1 ms; Motion Solver CPU 1484 sec
Model and Load Pre-processing for this 1st continuous sweep results - CPU 5 sec
We need to increase the sampling rate. A better solution should use a print of 0.02 ms (or less) instead of 0.1 ms.
5.3 Continuous sweep 1000-5000 RPM (20,200) Print 0.02 ms; Motion Solver CPU 3128 sec
Model and Load Pre-processing for this 2nd continuous sweep results (FFT) - CPU= 450 sec
6. Conclusion when comparing Discrete sweep with Continuous sweep driver solutions
Demonstration model and results (extract)Picture of the demonstration model provided
Waterfall color map results for a radial force reaction at a shaft bearing
Waterfall plot of a shaft radial acceleration
Data filesSimcenter3DMotion_Waterfall_Best_Practice_Sine_Sweep_v3.pdf
Simcenter3DMotion_Waterfall_Best_Practice_Sine_Sweep_v3.7z