Frequency Analysis of a rotating shaft

AIM:

To perform the frequency analysis of the rotating shaft using solidworks.

INTRODUCTION:

Natural frequency: Natural frequency, also known as eigenfrequency, is 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 nnormal mode.

Modes of vibration: A mode of vibration is characterized by a modal frequency and a mode shape. It is numbered according to the number of half waves in the vibration. For example, if a vibrating beam with both ends pinned displayed a mode shape of half of a sine wave (one peak on the vibrating beam) it would be vibrating in mode 1. If it had a full sine wave (one peak and one trough) it would be vibrating in mode 2.

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.

What is whirling of shaft?

It is defined as the speed at which a rotating shaft will tend to vibrate violently in the transverse direction if the shaft rotates in horizontal direction. In other words, the whirling or critical speed is the speed at which resonance occurs.

OBJECTIVE:

The main objective of the project is:

1. To make 3-D cad model of the rodtating shaft.
2. To perform frequency analysis and find out it's resonant frequency.

PROCEDURE:

1)Initially we make 2-D drawing of the shaft as per the desired dimensions shown below:

2)Then we convert this 2-D drawing to 3-D cad model by using revolve tool.Then we apply material as alloy steel.The isometric view of 3-D model of rotating shaft is shown below:

3)After this we perform frequency analysis of the shaft.For this first select simulation then click on new study and select frequency.

4)After that we apply material to the model as alloy steel and then apply bearing fixtures at the stepped end of the shaft and create fine mesh.The screenshot of fixture applied and meshed model is shown below:

5)After we finish with meshing click on run this study and wait for the results.The screenshot of analysis results is shown below and the animation link of vibration is also provided:

MODE 1:

The animation link for mode 1 is : https://youtu.be/Ooy0Jj_qG3k

MODE 2:

The animation link for mode 2 is : https://youtu.be/3Q8yL2dw3hU

MODE 3:

The animation link for mode 3 is : https://youtu.be/8_6NZjoqGcc

MODE 4:

The animation link for mode 4 is : https://youtu.be/7Sdsh5jyfxo

MODE 5:

The animation link for mode 5 is : https://youtu.be/gYPZ93spDVI

5)After that we click on results and select display resonant frequency.The screenshot of values of 5 modes of resonant frequency is shown below:

CONCLUSION:

1. Thus we have created the 3-D cad model of the rotating shaft and also their frequency analysis was also performed.
2. We have obtained the resonant frequency of 5 modes of vibration so we can say that if the shaft is rotated at this frequency then the shaft will get damage and failure of the system will occur.
3. The critical frequencies of the shaft are 688.07Hz,689.07Hz,1205.4Hz,2183.1Hz and 2185.4Hz respectively.

LINK FOR SOLIDWORKS PART FILE IS GIVEN BELOW:

https://drive.google.com/drive/folders/17B2D9HKiNOLpdxHFV2KKcDwPDc8RVBml?usp=sharing