Frequency Analysis of a rotating shaft

AIM: Conduct a frequency analysis and apply a bearing fixture on the stepped face of the rod at the two ends and perform the analysis. Find out 5 mode shapes and list the resonant frequencies

INTRODUCTION ON FREQUENCY ANALYSIS:

Frequency analysis is one of the most important analysis in an assembled components and a special case in a part that are involved in a kinematic motion.

Each and every part in the world has its natural frequency. when the assembled part of the component reaches its natural frequency, the body will fail.

EX: moving parts of the engine, suspension, vibrations in Banat of the car.

Mode shapes: we can generate various mode shapes by a change in material, fixtures, change in position of the bearings.

With help of the mode shapes, we can generate more cases for the frequency analysis.

According to our aim, we have to perform this analysis on two different cases, one the bearing at the center of the shaft and two the bearing at the step end of the shaft.

CASE 1: BEARING AT THE CENTRE OF THE SHAFT

MODEL: FIXTURES:

MESH: FREQUENCIES OF THE CASE 1:

MODES OF SHAPES:

1st mode shape	Shaft deflect in ‘Y’ direction
2nd mode shape	Shaft deflect in ‘X’ direction
3rd mode shape	Bearing has some deflection
4th mode shape	Deflection in ‘Y’ direction with “4” Nodes
5th mode shape	Deflection in ‘X’ direction with “4” Nodes

RESULTS OF CASE 1:

1^st mode shape: 2^nd mode shape:

3^rd mode shape: 4^th mode shape:

5^th mode shape:

CASE 2: BEARING AT THE STEP-END OF THE SHAFT

MODEL: FIXTURES:

MESH: FREQUENCIES OF THE CASE 2:

MODES OF SHAPES:

1st mode shape	Shaft deflect in ‘Y’ direction
2nd mode shape	Shaft deflect in ‘X’ direction
3rd mode shape	Deflection in ‘Y’ direction with “4” Nodes
4th mode shape	Deflection in ‘X’ direction with “4” Nodes
5th mode shape	Bearing has some deflection

RESULTS OF CASE 2:

1^st mode shape: 2^nd mode shape:

3^rd mode shape: 4^th mode shape:

5^th mode shape: