By www.Fastrackengine.com- Complete case study for design of tuned mass vibration absorber along with mathematical and practical validation.

1. Design Of Tuned MassDesign Of Tuned Mass
Vibration Absorber ToVibration Absorber To
Reduce Vibrations InReduce Vibrations In
Primary System.Primary System.
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2. Overview Of Vibration-
Vibration is the study of the repetitive motion
of objects. Vibration is caused by anything
that oscillates and it is transmitted through
continuous media.
When elastic bodies such as a spring, a beam
or a shaft are displaced from the equilibrium
position by the application of external forces,
and then released, they execute vibratory
motion.
Vibrations caused by a system effect other
systems, unless the systems are separated.

3. Causes of vibration-
Unbalanced forces in system.
Elastic nature of the system.
External excitations applied on the system.
Dry friction between two mating surfaces causes
vibration.
Vibration created by strong winds.
Earthquake or seismic activity.
Defects in assembly of machines such as broken
welds, loosely fitted bolts.

4. Effects Of Vibration-
(A) Desired Effects of vibrations:
Musical Instruments
Compacters
Vibratory Conveyers
Shakers
Stress Relieving
Hoppers
Sieves

5. (B) Undesirable Effects of vibrations:
Unwanted noise.
Loosening of the machines parts.
Excessive stresses induced in the system.
Vibration creates rapid wear of machine parts.
Due to heavy vibrations it is difficult to get exact &
Correct readings from the instruments.
Structural vibrations may collapse the structures such
as buildings, bridges etc.
Excessive vibration is harmful for humans (kinetosis).
‘Resonance’-which may lead to failure of component.

6. Methods of reducing vibrations-
(A) Removing external excitation if possible.
(B) There are certain advanced methods available to
reduce the vibrations to required level.
& These are,
1. Vibration Isolators
2. Vibration Dampers
3. Vibration Absorbers

7. Why we select Vibration Absorber-
Ease Of Design
Avoids Resonance
Ease Of Modification
No Effect Of Temperature On Working
Less Initial Cost
Less Modification Cost In Comparison
Compact In Nature

8. Objective-
To reduce the vibrations in a primary
system by adding an tuned mass vibration
absorber to the system so as to avoid
resonance & to achieve optimized
performance of machine or equipment.

9. How It Works?
The principle is that, if a system (Primary
system) has undesirable vibrations at an
operating frequency which approaches its
natural frequency, then to avoid vibrations a
secondary system (Absorber System) having its
natural frequency equal to the operating
frequency, is coupled to the Primary System to
reduce its amplitude to zero.

11. Design Procedure-
Fn1 = (1/2П ) (3E1 I1 /m1 l1³)1/2
Where:
Fn1
= Natural frequency of primary system(Hz)
m1
= End Mass of primary system(Kg).
E1=
Modulus of Elasticity of primary system(N/m2
).
I1=
Moment of inertia of primary system(m4
).
l1=
Length of primary system (m)

12. Fn2 = (1/2П ) (3E2 I2 /m2l2³)1/2
Where:
Fn2
= Natural frequency of absorber system(Hz)
m2
= End Mass of absorber system(Kg).
E2=
Modulus of Elasticity of absorber system(N/m2
).
I2=
Moment of inertia of absorber system(m4
).
l2=
Length of absorber system(m).
TO AVOIDE RESONANCE,
Fn1=
Fn2=
Fn(excitation)

13. Procedure of calculation of naturalProcedure of calculation of natural
frequency offrequency of
primary system:primary system:
l1
, b1 ,
t1

14. I1 = ( b1 * t1
3
) /12
Where,
I1 = Moment of inertia of cantilever beam(primary system)
b1= Width of cantilever beam (primary system)
t1 = Thickness cantilever beam (primary system)
(E1) From Design data book

17. Procedure of calculation of naturalProcedure of calculation of natural
frequency offrequency of
secondary system:secondary system:

19. VALIDATION
EXPERIMENTAL SET UP:

20. EXPERIMENTAL STEPS

21. GRAPH REPRESENTING EFFECT OF TUNED MASS VIBRATION ABSORBER
ON AMPLITUDE OF VIBRATION

22. Equipments Used-Equipments Used-
FFT Analyzer
Exciter
Oscillator
Accelerometer
NVGATE Software
Weighing Machine
Spring with end mass

23. Oscillator NVGATE Software
Weighing
Machine
Spring with end
mass
Primary system
Accelerometer
Exciter

24. Applications:
•Reciprocating machines.

26. •Vibration absorber in the transmission lines.

27. Analysis by comparingAnalysis by comparing
Unbalanced & balanced massUnbalanced & balanced mass
by ANSYSby ANSYS

28. Conclusion-
The use of tuned mass vibration absorber easily &
effectively enables us to protect primary system from
undesired self generated or external vibrations by
avoiding resonance & thereby leads to optimized the
performance of primary system.

29. REFERANCES-REFERANCES-
 “Mechanical Vibrations”, by G.K.Grover, Nem Chand
& Bros, Roorkee, U.K., India, 8th Edition, 2009.
“Mechanical Vibrations”, by
V.P.Singh,DhanpatRai&Com.Pvt.Ltd, Revised Edition
2009.
“Theory of Machines” by R.S.Khurmi, S.Chand
Publications Co Ltd India; 15th
Revised Edition,2006.
“Basic Vibration Theory”, Ralph E. Blake (e-book).
www.csaengineering.com

30. THANK YOU