Download - Basic Principles Ultrasonic Krautkramer
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Basic Principles of Ultrasonic Testing
Basic Principles ofBasic Principles ofUltrasonic TestingUltrasonic Testing
Theory and PracticeTheory and Practice
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingE l f ill tiExamples of oscillation
ball on pendulum rotatingball ona spring
pendulum rotatingearth
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic Testing
PulseThe ball starts to oscillate as soon as it is pushed
Pulse
Krautkramer NDT Ultrasonic Systems
p
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Basic Principles of Ultrasonic Testing
OscillationOscillation
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingMovement of the ball over time
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic Testing
Frequencyeque cy
Time
One full ill ti T
From the duration of one oscillation T th f f ( b f oscillation TT the frequency f (number of oscillations per second) is calculated:
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic Testing
The actual displacement a is termed as:
a180 36090 270
Time0
Phase
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingSpectrum of sound
Frequency range Hz Description ExampleFrequency range Hz Description Example
0 20 Infrasound Earth quake0 - 20 Infrasound Earth quake
20 - 20.000 Audible sound Speech, music
20 000 Ul d B Q l> 20.000 Ultrasound Bat, Quartz crystal
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingAt i t t
gas liquid solid
Atomic structures
gas liquid solid
low density weak bonding forces
medium density medium bonding
high density strong bonding forcesweak bonding forces medium bonding
forcesstrong bonding forces
crystallographic structure
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingU d t di tiUnderstanding wave propagation:
Spring = elastic bonding forceBall = atom
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic Testing
T
distance travelleddistance travelled
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic Testing
TDuring one oscillation T the wave f t t b th di t T front propagates by the distance :
Distance travelled
From this we derive:
or Wave equation
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingSound propagation
Di i f ill i
Direction of propagationLongitudinal waveDirection of oscillation
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingSound propagation
Direction of propagationTransverse waveDirection of oscillationDirection of oscillation
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingWave propagationLongitudinal waves propagate in all kind of materials.Longitudinal waves propagate in all kind of materials.Transverse waves only propagate in solid bodies. Due to the different type of oscillation, transverse wavesDue to the different type of oscillation, transverse wavestravel at lower speeds.Sound velocity mainly depends on the density and E-
d l f th t i lmodulus of the material.
AirWaterSteel, long
330 m/s1480 m/s
5920 m/sSteel, trans 3250 m/s
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingReflection and Transmission
A d t h i t i lAs 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:
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingB h i t i t fBehaviour at an interface
Medium 1 Medium 2
Incoming wave Transmitted waveIncoming wave Transmitted wave
Reflected wave
Interface
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingReflection + Transmission: Perspex - Steel
1,87
Incoming wave Transmitted wave
,
1 0Incoming wave Transmitted wave1,00,87
Reflected wave
Perspex Steel
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingReflection + Transmission: Steel - Perspex
1 0Incoming wave Transmitted wave
0 13
1,0
0,13
-0,87R fl t d
Perspex SteelReflected wave
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingA lit d f d t i iAmplitude of sound transmissions:
Water - Steel Copper - Steel Steel - Air
Strong reflection No reflection Strong reflection ith i t d h
pp
Double transmission Single transmission with inverted phase No transmission
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingPi l t i Eff tPiezoelectric Effect
+Battery
+y
Piezoelectrical Crystal (Quartz)
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingPi l t i Eff tPiezoelectric Effect
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The crystal gets thicker, due to a distortion of the crystal lattice
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingPi l t i Eff tPiezoelectric Effect
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The effect inverses with polarity change
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingPi l t i Eff t
S d
Piezoelectric Effect
Sound wave with
frequency f
U(f)
An alternating voltage generates crystal oscillations at the frequency f
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingPi l t i Eff tPiezoelectric Effect
Sh t lShort pulse( < 1 s )
A short voltage pulse generates an oscillation at the crystals resonantfrequency f0
Krautkramer NDT Ultrasonic Systems
q y 0
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Basic Principles of Ultrasonic TestingR ti f lt iReception of ultrasonic waves
A sound wave hitting a piezoelectric crystal induces crystalA sound wave hitting a piezoelectric crystal, induces crystal vibration which then causes electrical voltages at the crystal surfaces.
Electrical Piezoelectrical Ult ienergyPiezoelectrical crystal Ultrasonic wave
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingUltrasonic Probes
socket Delay / protecting facesocketcrystalDamping
Delay / protecting faceElectrical matchingCable Damping
Straight beam probe Angle beam probeTR-probe
Krautkramer NDT Ultrasonic Systems
St a g t bea p obe g e bea p obep obe
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Basic Principles of Ultrasonic TestingRF signal (short)
100100 ns
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingRF signal (medium)
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingSound field
Focus Angle of divergenceCrystalAccoustical axisAccoustical axis
D0
6
N
D0
Near field Far field
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingUltrasonic Instrument
0 2 4 8 106
Krautkramer NDT Ultrasonic Systems
0 2 4 8 106
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Basic Principles of Ultrasonic TestingUltrasonic Instrument
++-Uh
0 2 4 8 106
Krautkramer NDT Ultrasonic Systems
0 2 4 8 106
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Basic Principles of Ultrasonic TestingUltrasonic Instrument
+ -+Uh
0 2 4 8 106
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingUltrasonic Instrument
+
-Uv
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+ -Uh
0 2 4 8 106
Krautkramer NDT Ultrasonic Systems
0 2 4 8 106
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Basic Principles of Ultrasonic TestingBlock diagram: Ultrasonic Instrument
amplifier
horizontal IPscreen
sweep
clock
BE
clock
pulser
work piece
probepulser
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingSound reflection at a flaw
s
ProbeProbe
Flaw Sound travel path
Work piece
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingPlate testing
IP
BE
F
delaminationplate 0 2 4 6 8 10pIP = Initial pulseF = FlawBE Backwall echoBE = Backwall echo
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingWall thickness measurement
ss
0 2 4 6 8 10Corrosion 0 2 4 6 8 10Corrosion
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingThrough transmission testing
Th h i i i lThrough transmission signal
1 1T R
2T R0 2 4 6 8 10
2 2T R
Flaw
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingWeld inspection
a = s sina' = a - xF = probe anglea = a - xd' = s cos
s probe angles = sound patha = surface distancea = reduced surface distanced = virtual depth0 20 40 60 80 100
ad = 2T - t'
d virtual depthd = actual depthT = material thickness
a'd
x
s
dLack of fusionWork piece with welding
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic TestingStraight beam inspection techniques:
Direct contact, Direct contact, Fixed delaysingle element probe dual element probe
Fixed delay
Immersion testingThrough transmission
Krautkramer NDT Ultrasonic Systems
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Basic Principles of Ultrasonic Testing
1 2
Immersion testing
surface =
1 2
water delaysound entry
backwall flaw
IE IEIP IP1 2IE IE
BE BE
0 2 4 6 8 10 0 2 4 6 8 10
F
Krautkramer NDT Ultrasonic Systems