Frequency Analysis of a rotating shaft

INTRODUCTION:

A rotating shaft is a machine element, usually circular in cross-section, which is used to transmit power from one part to another, or from a machine that produces power to a machine that absorbs power.

AIM:

To create the model in Solidworks by assigning individual dimensions and to conduct the frequency analysis.

OBJECTIVE:

• To conduct a frequency analysis and apply a bearing fixture on the stepped face of the rod at the two ends and to perform the analysis.
• To find 5 mode shapes and list the resonant frequencies.

PROCEDURE:

• The rotating shaft is used to transmit power from one part to another.since it is fixed both the ends, it will experience various types of the frequency with respect to the rotation.
• The shaft was designed and it has 80mm diameter and length of the shaft will be 1000mm
• Stepped bars of 50mm diameter and 50mm length on both sides are attached.
• a central plate of 200mm diameter with width 25mm is fixed to the center of the shaft

• Then the simulation will be started by clicking the new study and the frequency will be selected for the study.
• Alloy steel will be selected as the material

Model Reference	Properties
	Name: Alloy Steel Model type: Linear Elastic Isotropic Default failure criterion: Max von Mises Stress Yield strength: 6.20422e+08 N/m^2 Tensile strength: 7.23826e+08 N/m^2 Mass density: 7700 kg/m^3 Elastic modulus: 2.1e+11 N/m^2 Poisson's ratio: 0.28 Thermal expansion coefficient: 1.3e-05 /Kelvin

The fixture was given on the both the stepped bars as the bearing fixture.

Model Reference	Connector Details
Bearing Support-1	Entities: 1 face(s) Type: Bearing
Bearing Support-2	Entities: 1 face(s) Type: Bearing

The mesh will be done with the default values but given a quite finer to obtain accurate results.

RESULTS:

The simulation will be done for five different modes and the resonant frequency will be obtained.

Name	Type	Min	Max
Amplitude1	AMPRES: Resultant Amplitude Plot for Mode Shape: 1(Value = 0.0132662 Hz)	0.002 Node: 5171	0.352 Node: 301

Name	Type	Min	Max
Amplitude2	AMPRES: Resultant Amplitude Plot for Mode Shape: 2(Value = 140.37 Hz)	1.168e-03 Node: 288	1.797e-01 Node: 2482

Name	Type	Min	Max
Amplitude3	AMPRES: Resultant Amplitude Plot for Mode Shape: 3(Value = 140.39 Hz)	6.633e-04 Node: 3280	1.797e-01 Node: 3166

Name	Type	Min	Max
Amplitude4	AMPRES: Resultant Amplitude Plot for Mode Shape: 4(Value = 631.696 Hz)	5.251e-04 Node: 664	2.873e-01 Node: 11109

Name	Type	Min	Max
Amplitude5	AMPRES: Resultant Amplitude Plot for Mode Shape: 5(Value = 631.778 Hz)	1.393e-04 Node: 1793	2.872e-01 Node: 332

CONCLUSION:

Frequency Number	Rad/sec	Hertz	Seconds
1	0.083354	0.013266	75.379
2	881.97	140.37	0.007124
3	882.1	140.39	0.007123
4	3969.1	631.7	0.001583
5	3969.6	631.78	0.0015828

After performing the frequency analysis on the rotating shaft, 5 modes of frequency had been calculated and it has been found that shaft vibrates more at 631hz. hence it is advised to design shaft in a way that it could not reach that frequency regularly.