Ecological Succession. ( ECOSYSTEM, B. Pharmacy, 1st Year, Sem-II, Environmen...
Use of ultrasound in metrology 2(1)
1. Prepared By :
• Mustafa ERARSLAN
• Serkan Ahmet ÇAM
• Osman KAYA
• Ferhat AYDIN
• Ahmet KOYUNCU
• Kadir YÜZER
2. Sound is a sequence of waves of
pressure that propagates through
compressible media such as air,water or
solids.
During propagation, waves can be
reflected, refracted, or attenuated by the
medium.
3. The mechanical vibrations that can be
interpreted as sound are able to travel
through all forms of matter: gases, liquids,
solids, and plasmas. The matter that
supports the sound is called the medium.
Sound cannot travel through a vacuum.
4. • Frequency, or its inverse, the period
• Wavelength
• Wavenumber
• Amplitude
• Sound pressure
• Sound intensity
• Speed of sound
• Direction
• Polarization (Transverse Waves)
5. Ultrasound is cyclic sound pressure with a frequency greater
than the upper limit of human hearing. Ultrasound is thus not separated
from "normal" (audible) sound based on differences in physical
properties, only the fact that humans cannot hear it. Although this limit
varies from person to person, it is approximately 20 kilohertz (20,000
hertz) in healthy, young adults. The production of ultrasound is used in
many different fields, typically to penetrate a medium and measure the
reflection signature or supply focused energy. The reflection signature
can reveal details about the inner structure of the medium, a property
also used by animals such as bats for hunting. The most well known
application of ultrasound is its use in sonography to produce pictures of
fetuses in the human womb. There are a vast number of other
applications as well.
6. Infrasound is sound that is lower in frequency than 20 Hz
(Hertz) or cycles per second, the "normal" limit of human hearing.
Hearing becomes gradually less sensitive as frequency decreases, so
for humans to perceive infrasound, the sound pressure must be
sufficiently high. The ear is the primary organ for sensing infrasound,
but at higher levels it is possible to feel infrasound vibrations in
various parts of the body.
The study of such sound waves is sometimes referred to as
infrasonics, covering sounds beneath 20 Hz down to 0.001 Hz. This
frequency range is utilized for monitoring earthquakes, charting rock
and petroleum formations below the earth, and also in
ballistocardiography and seismocardiography to study the mechanics
of the heart. Infrasound is characterized by an ability to cover long
distances and get around obstacles with little dissipation.
7. Acoustics is the interdisciplinary science that deals with the
study of all mechanical waves in gases, liquids, and solids including
vibration, sound, ultrasound and infrasound. A scientist who works in
the field of acoustics is an acoustician while someone working in the
field of acoustics technology may be called an acoustical engineer. The
application of acoustics can be seen in almost all aspects of modern
society with the most obvious being the audio and noise control
industries.
Hearing is one of the most crucial means of survival in the
animal world, and speech is one of the most distinctive characteristics
of human development and culture. So it is no surprise that the science
of acoustics spreads across so many facets of our society—music,
medicine, architecture, industrial production, warfare and more. Art,
craft, science and technology have provoked one another to advance
the whole, as in many other fields of knowledge.
8.
9. For Subsonic ;
where:
M = is Mach number
qc = is impact pressure (diffrence between total pressure and static pressure)
p = is static pressure
γ = is the ratio of specific heat of a gas at a constant pressure to heat at a
constant volume (1.4 for air).
High-
Regime Subsonic Transonic Sonic Supersonic Hypersonic
hypersonic
Mach <1.0 0.8–1.2 1.0 1.2–5.0 5.0–10.0 >10.0
11. Spectrum of sound
Frequency range
Description Example
Hz
0 - 20 Infrasound Earth quake
Audible
20 - 20.000 Speech, music
sound
> 20.000 Ultrasound
12. Atomic structures
gas liquid solid
•low density •medium density
•weak bonding forces •medium bonding •high density
forces •strong bonding
forces
•crystallographic
structure
13. Wave propagation
Longitudinal waves propagate in all kind of materials.
Transverse waves only propagate in solid bodies.
Due to the different type of oscillation, transverse waves
travel at lower speeds.
Sound velocity mainly depends on the density and E-modulus of
the material.
330 m/s
Air
Water 1480 m/s
Steel, long 5920 m/s
Steel, trans
3250 m/s
14. Reflection and Transmission
• As soon as a sound wave comes to a change in material
characteristics ,e.g. the surface of a workpiece, or an internal
inclusion, wave propagation will change too:
15. Behaviour at an interface
Medium 1 Medium 2
Incoming wave Transmitted wave
Reflected wave
Interface
22. Sound wave
with
frequency f
U(f)
An alternating voltage generates crystal oscillations at the
frequency f
23. Reception of ultrasonic waves
A sound wave hitting a piezoelectric crystal, induces
crystal vibration which then causes electrical voltages
at the crystal surfaces.
Electrical Piezoelectrical
Ultrasonic wave
energy crystal
24. amplifier
screen
IP horizontal
BE sweep
clock
pulser
probe
work piece
29. Immersion testing
1 2
surface = water delay
sound entry
backwall flaw
IP 1 IP 2
IE IE
BE BE
F
0 2 4 6 8 10 0 2 4 6 8 10
30. Weld inspection
ß = probe angle
a = s sinß s = sound path
F a = surface distance
a' = a - x a‘ = reduced surface distance
s
d' = s cosß d‘= virtual depth
d = actual depth
0 20 40 60 80 100 T= material thickness
d = 2T - t'
a
x a'
ß d
Lack of fusion
Work piece with welding s
31. Straight beam inspection techniques:
Direct contact, Direct contact, Fixed delay
single element probe dual element probe
Through transmission Immersion testing
32. • Sonar stands for sound navigation and ranging.
• Sonar uses a beam of sound waves and directs them
downward.
• After the sound wave hits the bottom of the ocean (ocean
floor), or an object, it will bounce off and return back causing
an echo.
• This is then recorded on a depth recorder on the ship.
• Some marine organisms use Echolocation, which is a form of
sonar (dolphins, whales, porpoises).
33. Active Passive
• Deploys and receives its • Listening device
own signal • Detects underwater
• Two categories echo sounds
ranging, and • Belongs to the Direct
communication Listening category
• Allied Submarine
Detection Investigation
Committee ( ASDICS)
34. Active Passive
• Transducer • Transducer (Only Receiver)
(Emitter/Receiver) • Indicator
• Indicator • Recorder
• Recorder • Computer System
• Computer System
35.
36.
37.
38. Diagnostic sonography (ultrasonography) is an ultrasound-
based diagnostic imaging technique used for visualizing
subcutaneous body structures including tendons, muscles, joints,
vessels and internal organs for possible pathology or lesions.
Obstetric sonography is commonly used during pregnancy and is
widely recognized by the public.
In physics, the term "ultrasound" applies to all sound waves
with a frequency above the audible range of human hearing, about
20,000 Hz. The frequencies used in diagnostic ultrasound are
typically between 2 and 18 MHz.
