Frequency Analysis of a rotating shaft
Objective
Conduct a frequency analysis on a stepped shaft as shown in model and obtaining list of resonant frequencies and 5 mode shapes.
CAD modelling
Create a stepped shaft of dimensions as shown in figure1 using tools like cirle and extruded boss/base.
Simulation Setup
Create a new frequency analysis study on the model created. Apply material as alloy steel. create two bearing fixtures on two stepped ends of shaft. Create a mesh of 4.07mm.In study properties set Number of frequency to 5. Run the simulation to analysise the results.
Results
5 mode shapes
Fig 2 First mode shape
Fig 3 Second mode shape
Fig 4 Third mode shape
Fig 5 Fourth mode shape
Fig 6 Fifth mode shape
List of Resonant Frequency
| Study name:rotating shaft | |||
| Mode No. | List of resonant Frequency(Rad/sec) | Frequency(Hertz) | |
| 1 | 0 | 0 | |
| 2 | 1498.8 | 238.54 | |
| 3 | 1498.9 | 238.55 | |
| 4 | 7642 | 1216.3 | |
| 5 | 7642.7 | 1216.4 |
Conclusion
If shaft rotates or vibrates at 1498.8 or 1498.9 or 7642 or 7642.7 rad/sec , the shaft will fail due to resonance.