VIBRATION MESUREMENT AND CONTROL

1. NOISE ,VIBRATION &HARSHNESS AND SAFETY
(2110006)
PRESENTED BY
1) MILAN KUNDALIA -160810102007 (8th semester auto mobile)
GIVEN TO : PROF. ANKIT PRAJAPATI

2. CONTENT:
 INTRODUTION
 TRANSDUCERS
 VIBROMETER
 TYPES OF DAMPER
 VIBRATION ABSORBER AND ISOLATOR
 VISCOUS DAMPING

3. INTRODUCTION
• Measurement should be made to produce the data
needed to draw meaningful conclusion from system under
test
• These data can be used to minimize or eliminate the
vibration and resultant noise
• The basic measurement system used for diagnostic
analyses of vibration consist of the three components
VIBARTION > PREAMPLIFIED > PROCESSING AND
PICKUP DISPLAY EQUIPMENT

4. TRANSDUCERS
• In general the transducers emplyed in vibration
analyses covert mechanical to electrical signal which is
the function of mechanical vibration

5. Transducers efficiency
,bandwidth and frequency
• Some transducers are specially fabricated to be more efficient
transmitters and other to be more efficient receivers
• Transducers perform well in one application will not always
produce the desired result in a different application
• It is also important to understand the concept of bandwidth
associated with a transducer
• The frequency noted on a transducer is the center frequency
and depend primarily on the backing material
• Highly damped tranducers will respond to frequency above and
below the central frequency

6. Classification of tranducers
1: Contact transducers are used for direct contact inspections,
and are generally hand manipulated. They have elements
protected in a rugged casing to withstand sliding contact with
a variety of materials. These transducers have an ergonomic
design so that they are easy to grip and move along a surface.

7. • 2. Immersion transducers do not contact the
component. These transducers are designed to
operate in a liquid environment and all connections
are watertight. Immersion transducers usually have an
impedance matching layer that helps to get more
sound energy into the water and, in turn, into the
component being inspected

8. • 3.dual element tranducers:-Two angled elements create a
V-shaped sound path in the test material. This "Pseudo-Focus"
enhances resolution in the focal zone. A dual element transducer
consists of two crystal elements housed in the same case,
separated by an acoustic barrier. One element transmits lon
gitudinal waves, and the other element acts as a receiver.

9. • 4:- Angle Beam Transducers and Wedges are used
primarily for testing of weld integrity. Their design allows
them to be easily scanned back and forth and provides a
short approach distance. Angle beam transducers are
single element transducers used with a wedge to
introduce a refracted shear wave or longitudinal wave into
a test piece.

10. • 5:-A piezoelectric transducer (also known as
a piezoelectric sensor) is a device that uses
the piezoelectric effect to measure changes in acceleration,
pressure, strain, temperature or force by converting this
energy into an electrical charge. A transducer can be
anything that converts one form of energy to another

11. VIBROMETER
• A laser Doppler vibrometer (LDV) is a scientific instrument that is used to make
non-contact vibration measurements of a surface. The laser beam from the LDV is
directed at the surface of interest, and the vibration amplitude and frequency are
extracted from the Doppler shift of the reflected laser beam frequency due to the
motion of the surface. The output of an LDV is generally a continuous analog
voltage that is directly proportional to the target velocity component along the
direction of the laser beam.

12. DAMPER
• Damping dissipates energy in the system,
which reduces the vibration level

13. TYPES OF DAMPER
• 1: hydraulic damper are most commonly used today the
dissipation of the energy in these damper occurred by
pumping oil through small orifices . Resistance of the
hydraulic damper increse with the increse of the speed of
spring deflection the resistance to spring movement can be
applied to the rebound stroke only

14. VBRATION ABSORBER AND ISOLATOR
• Difference between a vibration
absorber and a vibration isolator:
A vibration absorber is a device that can
absorb the vibration and make it's intensity
low while an isolator is device that can keep
apart the vibration between two surface or
system in contact in which one
is vibrate continuously

15. VISCOUS DAMPING
• Viscous damping is the dissipation of energy that occurs
when a particle in a vibrating system is resisted by a force
the magnitude of which is a constant, independent of
displacement and velocity, and the direction of which is
opposite to the direction of the velocity of the particle.