AIM: Perform a Frequency Analysis of a rotating shaft.

OBJECTIVE

1. Create the model in Solidworks according to dimensions that you see fit.
2. Perform frequency analysis on it.
3. Find out the resonant frequency.

RESONANCE

In physics, resonance describes the phenomenon of increased amplitude that occurs when the frequency of a periodically applied force is equal or close to a natural frequency of the system on which it acts. When an oscillating force is applied at a resonant frequency of a dynamical system, the system will oscillate at a higher amplitude than when the same force is applied at other, non-resonant frequencies.

Frequencies at which the response amplitude is a relative maximum are also known as resonant frequencies or resonance frequencies of the system.

MODEL

Dimension of model

3D MODEL

For this analysis, I give the alloy steel material to rotating shaft which has following material property:

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
Elastic modulus:	2.1e+11 N/m^2
Poisson's ratio:	0.28
Mass density:	7,700 kg/m^3
Shear modulus:	7.9e+10 N/m^2
Thermal expansion coefficient:	1.3e-05 /Kelvin

FREQUENCY ANALYSIS OF ROTATING SHAFT

Treated As	Volumetric Properties
Solid Body	Mass:0.947968 kg Volume:0.000123113 m^3 Density:7,700 kg/m^3 Weight:9.29009 N

FIXTURE AND MESH

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

Mesh type	Solid Mesh
Mesher Used:	Standard mesh
Element Size	2 mm
Mesh Quality	High

PROCEDURE

1. First, we have to create model of rotating shaft according dimension.
2. Then go to simulation.
3. Create the frequency analysis study.
4. Apply the material to rotating shaft.
5. Give the bearing support at the both end of the shaft.
6. Create mesh of 2 mm.
7. Run the simulation.

RESULTS

Name	Type	Min	Max
Amplitude1	AMPRES: Resultant Amplitude Plot for Mode Shape: 1(Value = 0.119085 Hz)	5.853e-05 Node: 103185	2.009e+00 Node: 1634

Name	Type	Min	Max
Amplitude2	AMPRES: Resultant Amplitude Plot for Mode Shape: 2(Value = 199.974 Hz)	1.101e-03 Node: 55755	1.188e+00 Node: 8438

Name	Type	Min	Max
Amplitude3	AMPRES: Resultant Amplitude Plot for Mode Shape: 3(Value = 199.978 Hz)	2.939e-05 Node: 151712	1.188e+00 Node: 8442

Name	Type	Min	Max
Amplitude4	AMPRES: Resultant Amplitude Plot for Mode Shape: 4(Value = 1,022.27 Hz)	2.424e-04 Node: 101066	2.101e+00 Node: 1372

Name	Type	Min	Max
Amplitude5	AMPRES: Resultant Amplitude Plot for Mode Shape: 5(Value = 1,022.29 Hz)	3.213e-04 Node: 101117	2.101e+00 Node: 151425

RESONANCE FREQUENCY

Frequency Number	Rad/sec	Hertz	Seconds
1	0.74824	0.11909	8.3973
2	1,256.5	199.97	0.0050006
3	1,256.5	199.98	0.0050005
4	6,423.1	1,022.3	0.00097821
5	6,423.3	1,022.3	0.00097819

CONCLUSION

From the analysis we find the resonance frequency of rotating shaft. So, we can not run the system at above resonance frequency and shaft can withstand the same load at another frequency.

If we run the system nearly at resonance frequency, rotating shaft has high amplitude so it may be failing or permeant deform.