Frequency Analysis of a rotating shaft

Aim :- To find out the critical frequencies of a rotating shaft in Solidworks.

• INTRODUCTION:

Resonant frequency is the oscillation of a system at its natural or unforced resonance. Resonance occurs when a system is able to store and easily transfer energy between different storage modes, such as Kinetic energy or Potential energy as find with a simple pendulum.

• Resonance: -

"The increase in amplitude of oscillation of an electric or mechanical system exposed to a periodic force whose frequency is equal or very close to the natural undamped frequency of the system."

• Mode:-

The mode is a statistical term that refers to the most frequently occurring number found in a set of numbers. The mode is found by collecting and organizing data in order to count the frequency of each result. The result with the highest count of occurrences is the mode of the set, also referred to as the modal value.

• Mode Shapes:-

The deformed shape of the structure at a specic natural frequency of vibration is termed its normal mode of vibration. Some other terms used to describe the normal mode are mode shape, characteristic shape, and fundamental shape. Each mode shape is associated with a specic natural frequency. Modes are inherent properties of a structure, and are determined by the material properties (mass, damping, and stiffness), and boundary conditions of the structure. Each mode is dened by a natural (modal or resonant) frequency, modal damping, and a mode shape (i.e. the so-called “modal parameters”).

• 3D Modelling of Rotating shaft :-

The above shown model was made using solidworks and subjected to frequency analysis.

• Preprocessing :- Boundary Conditions

• Material Applied :- Alloy Steel

• Fixture:- The stepped ends of the shafts were Bearing Supported.

• Meshing:- A mesh of fine size and tolerance of 0.3mm was applied.

• After applying all the boundry condition, model is ready to run the study.

Results :-

• Mode Shape 1

• Mode Shape 2

• Mode Shape 3

• Mode Shape 4

• Mode Shape 5

• List of Resonant Frequencies

• Comparison of result :-