Frequency Analysis of a rotating shaft
Frequency Analysis of a rotating shaft
Aim: To find out the critical frequencies of a rotating shaft in Solidworks.
Introduction: For any system, the natural frequency is defined as the frequency at which a system tends to oscillate in the absence of any driving or damping force. The motion pattern of a system oscillating at its natural frequency is called the normal mode (if all parts of the system move sinusoidally with that same frequency).
in a mass-spring system, with mass m and spring stiffness k, the natural frequency can be calculated as
(in case of a shaft or beam the stiffness k depends upon the young's modulus, area of cross-section, and length as
k=EA/L)
If the oscillating system is driven by an external force at the frequency at which the amplitude of its motion is greatest (close to a natural frequency of the system), this frequency is called resonant frequency.
The resonance is harmful to our component because it can fail the system. Hence it is necessary to find out the frequencies at which resonance can happen.
Problem Specification: Conduct a frequency analysis on the rotating shaft and apply a bearing fixture on the stepped face of the rod at the two ends and perform the analysis and find out 5 mode shapes and list the resonant frequencies
Model: Model is created using the given image.
Frequency Analysis:
Steps To Follow:
1) Create the model with appropriate dimensions.
2) Go to Solidworks Add-Ins and click simulation.
3) click new study then frequency analysis.
4) Provide material to the shaft (alloy steel)
5) Provide bearing fixtures at both the stepped ends.
6) create the mesh
7) now run the simulation.
Result Plots:
Resonating Frequencies:
Mode No. Frequency(Rad/sec) Frequency(Hertz) Period(Seconds)
1 0.58999 0.0939 10.65
2 3,639.2 579.2 0.0017265
3 3,639.7 579.27 0.0017263
4 12,293 1,956.5 0.00051113
5 12,297 1,957.1 0.00051095
Animations:
https://drive.google.com/file/d/11p7KgC3ao7M7mh_-R4kFNTZ_yvHQczrz/view?usp=sharing
Conclusion:
In order to avoid the resonance frequency of oscillation should not reach the critical frequency.
Reference:
Skill Lync course
Files:
https://drive.google.com/drive/folders/1lizL4NiIZ2TxeEQsfgJftWY4ld97B1SA?usp=sharing