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Page 1: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range
Page 2: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Introduction to the Physics of Ultrasound

Page 3: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Sound?•Sound is a longitudinal wave that travels in a straight line

•Sound requires a medium for traveling

Range of audible sound20Hz -20kHz

Range of audible sound20Hz -20kHz

Page 4: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range
Page 5: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

When a longitudinal wave moves through

a material, the particles of the material move backwards and forwards along the direction in which the wave is travelling.

When a longitudinal wave moves through

a material, the particles of the material move backwards and forwards along the direction in which the wave is travelling.

The wavelength of a longitudinal wave can be measured as the distance between the centre of two compressions

The wavelength of a longitudinal wave can be measured as the distance between the centre of two compressions

Page 6: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Below is a picture of a longitudinal wave travelling along a spring.

Below is a picture of a longitudinal wave travelling along a spring.

Page 7: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

•Ultrasonic wave is a longitudinal wave with a frequency exceeding the upper limit of human hearing, which is 20 kHz.

Ultrasonic wave

Page 8: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

ULTRASONIC WAVE

Frequency greater than audible sound (f>20kHz).

Page 9: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

ULTRASONICS

- Frequency greater than audible sound.

INFRASONICS

-Frequency lesser than

audible sound

SUPERSONIC – Speed greater than

sound.

Page 10: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

General Properties of UltrasonicsAcoustic wavesFrequency > 20kHzHigh energy wavesSpeed in a thin rod v = (Y/ρ)1/2 ,in

liquid (K/ρ)1/2 in gas (γP/ ρ)1/2

Speed depends on frequency. Greater the frequency, higher the velocity

Modes of propagation- longitudinal & transverse

Can be reflected, refracted & diffracted

Page 11: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Heating effectStirring effect.Attenuation A=A0 e –αx

Can be transmitted through large distances

Stationary waves are produced

Page 12: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Piezo-electric effect• When crystals like quartz,

tourmaline etc. are subjected to stress along the mechanical axis, a P.D is developed across the perpendicular electrical axis.

• This is called Piezo electric effect

• Discovered by J & P. Curie• Converse of this effect is also possible.

Page 13: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Converse piezo electric effect• When a P.D is applied between the

two opposite faces of a crystal, then stress or strain is induced along the perpendicular faces.

• If frequency of osculation is equal to the natural frequency of the crystal, resonance takes place and ultrasonics are produced.

Page 14: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Krautkramer NDT Ultrasonic Systems

Piezoelectric Effect

Piezoelectrical Crystal (Quartz)

Battery

+

Page 15: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Krautkramer NDT Ultrasonic Systems

+

The crystal gets thicker, due to a distortion of the crystal lattice

Piezoelectric Effect

Page 16: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Krautkramer NDT Ultrasonic Systems

+

The effect inverses with polarity change

Piezoelectric Effect

Page 17: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Krautkramer NDT Ultrasonic Systems

An alternating voltage generates crystal oscillations at the frequency f

U(f)

Sound wave with

frequency f

Piezoelectric Effect

Page 18: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Piezo electric crystals

• Piezoelectric crystal: a crystal that exhibits piezo electric effect is called piezo electric crystals

• Eg:- Quartz, tourmaline, Rochelle salt etc

Page 19: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Piezoelectric Crystals

• The thickness of the crystal determines the frequency of the scanhead

Low Frequency3 MHz

High Frequency10 MHz

Page 20: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Piezoelectric generator

Page 21: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

The circuit is basically a Hartley oscillator.

The tank circuit produces high frequency alternating potential which is fed to the quartz crystal.

Page 22: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

• Tank circuit• To produce high

frequency alternating potential.

• The frequency v

LC

2

1

Page 23: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Piezoelectric generator

• This is based on the converse Piezo electric effect .

• When the frequency of oscillation coincides with the natural frequency of the crystal, resonance will take place.

• This principle is used for the production of ultrasonics.

Page 24: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

• Frequency up to 15 MHz can be produced by this method.

Page 25: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

• .

Y

lLC

Y

lcrystalofnoscillatiooffrequencythe

l

vFrequency

lv

l

v

YvsultrasonicofVelocity

LCcircuitTankoffrequencyThe

2

1

2

1

2

1

2

2.

2

2

1

Page 26: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Magnetostriction

Magnetostriction is a property of magnetic materials that causes them to change their shape when subjected to a magnetic field. The effect was first identified bby James Joule

James Prescott Joule, (1818 – 1889)

Page 27: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

• When a ferromagnetic rod is placed in an alternating M.F, with its length parallel to the field, the length of the rod increases and decreases rapidly (or the rod vibrates) This phenomena is known as Magnetostriction.

• This principle is used to produce ultrasonic waves

Magnetostriction

Page 28: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

FREQUENCY

The frequency generated is given by

rodtheoflengththel

rodofdensitythe

ulussyoungYwhere

Y

l

.

mod'

2

1

Page 29: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

APPLICATIONS

Page 30: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

DEPTH OF SEA

Page 31: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range
Page 32: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range
Page 33: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Bats navigate using ultrasound

Page 34: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

ULTRASONIC MIXINGULTRASONIC MIXING

Page 35: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

SOUND SIGNALING

Page 36: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

SOLDERING & METAL CUTTING

SOLDERING & METAL CUTTING

Page 37: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range
Page 38: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range
Page 39: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

CLEANING

Page 40: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range
Page 41: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

STERILIZINGSTERILIZING

Page 42: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

BIOLOGICAL EFFECTBIOLOGICAL EFFECT

Page 43: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

MEDICAL FIELDMEDICAL FIELD

Page 44: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

DIAGNOSIS

THERAPYTHERAPY

Page 45: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Ultrasound imaging: How does it work?

• An ultrasound element acts like a bat.

• Emit ultrasound and detect echoes

• Map out boundary of object

Page 46: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

More about how it works…

• The probe contains a transmitter and a receiver.

A pulse of ultrasound is sent out by the transmitter.

The pulse is reflected from a surface and returns to the receiver.

The ultrasound machine measures how long it takes for the pulse to return

Ultrasound probe

Body tissue(muscle etc)

skin

Page 47: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Ultrasound imaging: foetus feet

This is a 2D ultrasound scanthrough the foot of a foetus. You can see some of the bones of the foot.

Page 48: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Ultrasound imaging: more surface rendering

Page 49: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Ultrasound imaging: imaging the heart

heart valves

atrium

ventricle

Page 50: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Why Use Ultrasound?

• Ultrasound is very safe. There is no firm evidence that it does any harm to the body (or the baby in the case of pregnancy scans).

• X-rays are potentially dangerous, particularly to young children and pregnant women (they damage the unborn baby).

Page 51: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

COAGULATION & CRYSTALLIZATIONCOAGULATION & CRYSTALLIZATION

Page 52: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

FORMATION OF ALLOYS

Page 53: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

TO FIND VELOCITY OF SOUND IN GASES &

LIQUID

TO FIND VELOCITY OF SOUND IN GASES &

LIQUID

Page 54: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

NON DESTRUCTIVE TESTING

NON DESTRUCTIVE TESTING

Page 55: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Non destructive testing is a new method of testing of material Without destruction of the material

This can be used to detect the imperfections like flaws , cracks , breakings, cavity, airpockets, discontinuities etc in material

Page 56: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Aircraft Inspection• Nondestructive testing is used

extensively during the manufacturing of aircraft.

Page 57: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Pulse echo system

Pulse transmission system

Pulse resonance system

Page 58: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Pulse echo system

Page 59: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

back surface echo

Page 60: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

High frequency sound waves are introduced into a material and they are reflected back from surfaces or flaws.

Reflected sound energy is displayed versus time, and inspector can visualize a cross section of the specimen showing the depth of features that reflect sound. f

plate

crack

0 2 4 6 8 10

initial pulse

crack echo

Oscilloscope, or flaw detector screen

Ultrasonic Inspection (Pulse-Echo)

Page 61: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Pulse transmission system

Page 62: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Advantages of Ultrasonic testing

1. Simple and accurate

2. Very minute flows can be detected

3. Nature, size and location of defect can be accurately determined

4. Cheap method

5. Used as high speed testing

6. Large specimen can be inspected in a short time.

Page 63: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Ultrasonic diffractometer

• To find the velocity and wavelength of ultrasonics

• a quartz crystal is set into vibrations in a liquid using an R.F oscillator.

• Ultasonics produced

• This makes the liquid an aquastic grating

• Collimated sodium light allowed to fall normally on the grating

Page 64: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Ultrasonic diffractometer.

Page 65: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

Procedure

Page 66: Introduction to the Physics of Ultrasound Sound? Sound is a longitudinal wave that travels in a straight line Sound requires a medium for traveling Range

• Diffraction takes place

• d sin θ= nλ--------(1) where d= the distance between 2 nodal or antinodal planes

• d= λa/2 or λa= 2d

• V=טλa