vibration control on machine seminar ppt

1. VIBRATION CONTROLE ON MACHINE
Presented byVipin Chaudhary
1512240236 ME-88

2.  Machine and its components
 Vibration
 MachiningVibration
 Vibration Control
 Methods of vibration control
 Effects of vibration
 Conclusion

3.  A machine is a tool that consists of one or more parts, and
uses energy to meet a particular goal. Machines are usually
powered by mechanical, chemical, thermal, or electrical
means, and are often motorized.
 Machine component refers to an elementary component of
a machine.These are generally of three types-
1. Structural component: Shaft, Coupling, Bearing etc.
2. Mechanical component: Chain, Brake, Cam & Follower etc.
3. Control component: Switches, Indicators, Sensors etc.

4.  Vibration is a mechanical
phenomenon by which oscillations
occur about an equilibrium point.
For ex: Vibration of mobile
phones, cone of a loudspeaker etc.
 More often, vibration is
undesirable, wasting energy and
creating unwanted sound – noise.
For ex: the vibrational motions of
engines, electric motors, or any
mechanical device.
 The figure shows one of the
possible modes of vibration of a
circular drum.

5.  Free vibration occurs when a mechanical system is set off
with an initial input and then allowed to vibrate freely.
Examples of this type of vibration are pulling a child back on
a swing and then letting go.
 Forced vibration is when a time-varying disturbance (load,
displacement or velocity) is applied to a mechanical system.
The disturbance can be a periodic, steady-state input, a
transient input, or a random input.
Examples of these types of vibration include a shaking
washing machine due to an imbalance.

6.  It is the process of reducing the effect of vibration in machine
component.
 In refineries or plants snubbers are often used for vibration
control.
 Snubbers come in two different variations: hydraulic snubber
and a mechanical snubber.
 The methods of vibration control are discussed as follows

7.  Damped MachiningTools
 Balancing of Rotating Mass
 Vibration Isolation
 Dynamic vibration absorber
 Active vibration control
 Input Shaping

8.  Damped machining tools refer to a series of machining tool
which are damped to suppress severe vibrations during
machining process.
 It is of two types-
1. Active damping tools: The active damping tools utilize a
compensating force to the vibrating object in the reversed vibrating
direction.
2. Passive damping tools: The passive damping tools can be divided
into constrained layer damping tools and tuned mass dampers.

9. • Vibration isolation is the process of isolating an object, such
as a piece of equipment, from the source of vibrations.
• This process of controlling vibration is done by two methods-
1. Active vibration isolation: It is also known as electronic force
cancellation system. It employes electric power, sensors, actuators, and
control systems.
• Sensors for active isolation- Piezoelectric accelerometers, MEM
accelerometers, Geophones, Piezoelectric force sensors, Proximity
sensors, Interferometers.
• Actuators for Active Isolation: Linear motors, Pneumatic actuators,
Piezoelectric motors

10.  A dynamic vibration absorber , is a tuned spring-mass
system which reduces or eliminates the vibration of a
harmonically excited system.
 A dynamic absorber can be affixed to the rotating machine
and tuned to oscillate in such a way that exactly counteracts
the force from the rotating imbalance.
 Dynamic absorbers differ from tuned mass dampers.

11.  A bushing is a type of vibration isolator.
 A common application is in vehicle suspension systems,
where a bushing made of rubber.
 A rubber bushing may also be described as a flexible
mounting or antivibration mounting.
 The advantages of a bushing is less noise and vibration are
transmitted & requires no lubrication.
 The disadvantages of Rubber bushings are it can deteriorate
quickly in the presence of oils & adversely affect the vehicle's
handling when used in suspension system.

12.  Unnecessary vibration in machine
components occurs.
 Unwanted noise.
 Excessive stresses in machine elements.
 Reduce the reliability.
 Failure in bearings in short time periods.
 Fatigue failure occurs.

13.  The vibration is an undesirable process but some times it is
desirable also.The vibration of machine components is an
undesirable process which results in failure of the machine. It
prevents the machine from working efficiently. So isolating
the vibration in machines is very important.We have
discussed about some isolating techniques for reducing the
vibration of machine components.We should adapt those
techniques and apply them to the machines so that we can
perform efficient working with the machines and the energy
losses and machine failure can be stopped.