FREQUENCY ANALYSIS OF A ROTATING SHAFT USING SOLIDWORKS

1.AIM :

TO MODEL AND FIND OUT THE CRITICAL FREQUENCIES OF A ROTATING SHAFT USING SOLIDWORKS

2.OBJECTIVES :

1. To model a shaft in solidworks.
2. To conduct a frequency analysis of a rotating shaft using Solidworks simulation and find out 5 mode shapes and list the resonant frequencies.

3.INTRODUCTION :

Every structure has the tendency to vibrate at certain frequencies, called natural or resonant frequencies. Each natural frequency is associated with a certain shape, called mode shape, that the model tends to assume when vibrating at that frequency.

When a structure is properly excited by a dynamic load with a frequency that coincides with one of its natural frequencies, the structure undergoes large displacements and stresses. This phenomenon is known as resonance.

For undamped systems, resonance theoretically causes infinite motion. Damping, however, puts a limit on the response of the structures due to resonant loads.

If a design is subjected to dynamic environments, static studies cannot be used to evaluate the response. In that case Frequency analysis help to avoid resonance and design vibration isolation systems. They also form the basis for evaluating the response of linear dynamic systems where the response of a system to a dynamic environment is assumed to be equal to the summation of the contributions of the modes considered in the analysis.

Here in this work a shaft is modelled using Solidworks and further frequency analysis on the shaft is performed using Solidworks simulation, 5 mode shapes and their respective resonant frequencies are found.

4.MODEL :

A shaft is modelled in solidworks as per the dimensions shown below.

5.PROCEDURE :

• Using solidworks simulation create a new frequency analysis study.
• Assign material to the model, here Alloy steel is selected as the material.

Mass properties : Density = 0.01 gm/mm^3

Mass = 4160.73 gms

Volume = 540353.94 mm^3

Surface area = 62831.85 mm^2

• A bearing fixture is applied on the stepped face of the rod at the two ends and perform the analysis.

• A standard mesh of size 7mm is applied.

Mesh Details : Mesh Type- Solid Mesh

Element Size- 7mm

Total Nodes- 17348

Total Elements- 10927

• Finally run the frequency analysis.

6.RESULTS :

5 different modes are found and each formed with different natural frequency.

MODE 1

MODE 2

MODE 3

MODE 4

MODE 5

8.REFERENCES :

http://help.solidworks.com/2017/english/solidworks/cworks/c_frequency_analysis.htm