Frequency Analysis of a rotating shaft

Aim:

To find out the critical frequencies of a rotating shaft.

Given data:

A geometry without dimensions.

Bearing Fixture has to be located at both the ends of the stepped shaft.

Solution Procedure:

• CAD Modelling:

All the dimensions are assumed from the above geometry.

• Material Assumed:

Applied default material is Alloy Steel.

• Applying Boundary Conditions:
• Bearing fixture is assigned to both the stepped ends.
• A centrifugal force for angular velocity 120 rad/s is assigned to the shaft.

• Meshing of geometry:

Results of Frequency Analysis:

• There are 5 mode shapes in total.

Shape 1:

Shape 2:

Shape 3:

Shape 4:

Shape 5:

Resonant Frequencies:

The above table shows the list of resonant frequencies at which if the natural frequency of a system matches, will undergo instability.