Frequency analysis of a rotating shaft using Solidworks FEA Simulation

Aim:

To perform modal/frequency analysis on a rotating shaft in Solidworks.

Objective:

• To perform modal/frequency analysis on a rotating shaft.
• To obtain the resonant frequencies and mode shapes.

Theory:

In mechanical systems, resonance is a phenomenon that only occurs when the frequency at which a force is periodically applied is equal to the natural frequency of the system on which it acts. This causes the system to oscillate with a larger amplitude than when the force is applied at other frequencies. Frequencies at which the response amplitude is maximum as also known as resonant frequencies of the system.

A mode shape is a specific pattern of vibration executed by a mechanical system at a specific frequency. Different mode shapes will be associated with different frequencies. Mode shapes also depend on the nature of the material and its dimension. If two specimens of the same material but with different dimensions are vibrated with a single frequency, a change in the mode shape is observed.

Setup Explanation:

1. First, the shaft is modelled using the appropriate dimensions as shown.

2. Then, under simulation option click on new study and create a new frequency study.
3. Right click on the shaft and set material as alloy steel.
4. Create bearing supports at the ends of the shaft steps as shown.

5. Create a mesh with the default settings as shown and run the study.

Results:

1. Mode 1:

2. Mode 2:

3. Mode 3:

4. Mode 4:

5. Mode 5:

Observation:

Conclusion:

1. The resonant frequencies and corresponding amplitudes of the shaft are obtained.
2. The shaft should not be rotated at the velocity corresponding to the critical frequencies to avoid failure.

File Link:

https://drive.google.com/drive/folders/1fNN-VSqNxJTH8Q1F9eExHwQmLTgBFFCZ?usp=sharing