Frequency Analysis of a rotating shaft
Objective: Perform the frequency analysis of the rotating shaft. also, find out the resonance frequency and critical frequency.
Introduction :
Here I took the one rotating shaft and one rotor is mounted on that shaft.
Dimensions:
Material 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 |
|
Volumetric Properties |
|
Mass:1.62307 kg Volume:0.000210788 m^3 Density:7700 kg/m^3 Weight:15.9061 N
|
Procedure:
Take a new study. select the Frequency test. Apply the material Alloy steel. apply the boundary condition. Apply the bearing fixture on the stepped face of the shaft at the two and perform the analysis.
study Properties:
|
Study Name |
Frequency |
|
Analysis type |
Frequency |
|
Mesh type |
Solid Mesh |
|
Number of frequencies |
5 |
|
Solver type |
FFEPlus |
|
Soft Spring: |
Off |
Figure Of mesh in shaft:
Study Result:
|
Name |
Type |
Min |
Max |
|
Amplitude1 |
AMPRES: Resultant Amplitude Plot for Mode Shape: 1(Value = 1041.4 Hz) |
0.00000 Node: 1 |
1.00298 Node: 327 |
|
shaft test-Frequency 1-Amplitude-Amplitude1 |
|
Name |
Type |
Min |
Max |
|
Amplitude2 |
AMPRES: Resultant Amplitude Plot for Mode Shape: 2(Value = 1042.88 Hz) |
0.000 Node: 1 |
1.003 Node: 265 |
|
shaft test-Frequency 1-Amplitude-Amplitude2 |
|
Amplitude3 |
AMPRES: Resultant Amplitude Plot for Mode Shape: 3(Value = 1335.49 Hz) |
0.000 Node: 1 |
1.786 Node: 714 |
|
shaft test-Frequency 1-Amplitude-Amplitude3 |
|
Name |
Type |
Min |
Max |
|
Amplitude4 |
AMPRES: Resultant Amplitude Plot for Mode Shape: 4(Value = 2815.43 Hz) |
0.000 Node: 1 |
2.331 Node: 277 |
|
shaft test-Frequency 1-Amplitude-Amplitude4 |
|
Name |
Type |
Min |
Max |
|
Amplitude5 |
AMPRES: Resultant Amplitude Plot for Mode Shape: 5(Value = 2816.58 Hz) |
0.000 Node: 1 |
2.330 Node: 6903 |
|
shaft test-Frequency 1-Amplitude-Amplitude5 |
Result:
Mode List
|
Frequency Number |
Rad/sec |
Hertz |
Seconds |
|
1 |
6543.3 |
1041.4 |
0.00096025 |
|
2 |
6552.6 |
1042.9 |
0.00095888 |
|
3 |
8391.1 |
1335.5 |
0.00074879 |
|
4 |
17690 |
2815.4 |
0.00035519 |
|
5 |
17697 |
2816.6 |
0.00035504 |
Here in the above table, we have the resonance frequency of the shaft If our system is vibrated the same as the shaft frequency our system will fail. We have to make sure that our system should not vibrate at any above-given frequency.