basic ultrasonic training
TRANSCRIPT
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 1
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Basic Principles ofBasic Principles of
Ultrasonic TestingUltrasonic Testing
Theory and PracticeTheory and Practice
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 2
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Examples of oscillationExamples of oscillation
ball ona spring
pendulum rotatingearth
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 3
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
The ball starts to oscillate as soon as it is pushed
Pulse
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 4
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Oscillation
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Movement of the ballball over time
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Time
One full oscillation T
Frequency
From the duration of one oscillation T the frequency f (number of oscillations per second) is calculated:
Tf
1T
f1
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
180 36090 270Phase
Time
a
0
The actual displacement a is termed as:
sin A a sin A a
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
SpectrumSpectrum ofof soundsound
Frequency range Hz Description Example
0 - 20 Infrasound Earth quake
20 - 20.000 Audible sound
Speech, music
> 20.000 Ultrasound Bat, Quartz crystal
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 9
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
gas liquid solid
Atomic structuresAtomic structures
low densityweak bonding forces
medium densitymedium bonding forces
high density strong bonding forcescrystallographicstructure
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Understanding wave propagation:Understanding wave propagation:
Spring = elastic bonding force
Ball = atom
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
T
distance travelled
start of oscillation
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
T
Distance travelled
From this we derive:
or Wave equation
During one oscillation T the wave front propagates by the distance :
Tc
Tc f c f c
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Direction of oscillation
Direction of propagationLongitudinal wave
Sound propagationSound propagation
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Direction of oscillation
Direction of propagationTransverse wave
Sound propagationpropagation
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Wave propagationpropagation
AirWaterSteel, longSteel, trans
330 m/s1480 m/s
3250 m/s
5920 m/s
Longitudinal waves propagate in all kind of materials.Transverse waves only propagate in solid bodies. Due to the different type of oscillation, transverse wavestravel at lower speeds.Sound velocity mainly depends on the density and E-modulus of the material.
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Reflection and Reflection and TransmissionTransmission
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:
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 17
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Behaviour at an interfaceBehaviour at an interface
Medium 1 Medium 2
Interface
Incoming wave Transmitted wave
Reflected wave
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Incoming wave Transmitted wave
Reflected wave
Perspex Steel
1,87
1,00,87
Reflection + Transmission: Perspex - SteelReflection + Transmission: Perspex - Steel
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
0,13
1,0
-0,87
Perspex Steel
Reflection + Transmission: Steel - PerspexReflection + Transmission: Steel - Perspex
Incoming wave Transmitted wave
Reflected wave
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Amplitude of sound transmissions:Amplitude of sound transmissions:
strong reflection
double transmission
no reflection
singletransmission
strong reflection with inverted phase
no transmission
Water - Steel Copper - Steel Steel - Air
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Piezoelectric EffectPiezoelectric Effect
Piezoelectrical Crystal (Quartz)
Battery
+
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
+
The crystal gets thicker, due to a distortion of the crystal lattice
Piezoelectric EffectPiezoelectric Effect
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
+
The effect inverses with polarity change
Piezoelectric EffectPiezoelectric Effect
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 24
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
An alternating voltage generates crystal oscillations at the frequency f
U(f)
Sound wave with
frequency f
Piezoelectric EffectPiezoelectric Effect
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 25
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
A short voltage pulse generates an oscillationat the crystal‘s resonant frequency f0
Short pulse ( < 1 µs )
Piezoelectric EffectPiezoelectric Effect
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 26
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Reception of ultrasonic wavesReception of ultrasonic waves
A sound wave hitting a piezoelectric crystal, induces crystal vibration which then causes electrical voltages at the crystal surfaces.
Electrical energy
Piezo-electrical crystal
Ultrasonic wave
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 27
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
socket
crystal
Damping
Delay / protecting face
Electrical matching
Cable
Ultrasonic ProbesUltrasonic Probes
Straight beam probe Angle beam probeTR-probe
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
100 ns
RF signal (short)RF signal (short)
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
RF signal (medium)RF signal (medium)
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
N
Near field Far field
Focus Angle of divergenceCrystalAccoustical axis
D0
6
Sound fieldSound field
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Ultrasonic InstrumentUltrasonic Instrument
0 2 4 8 106
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
0 2 4 8 106
+-Uh
Ultrasonic InstrumentUltrasonic Instrument
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
0 2 4 8 106
+ -Uh
Ultrasonic InstrumentUltrasonic Instrument
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 34
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
0 2 4 8 106
+
+
-
-
U
U
h
v
Ultrasonic InstrumentUltrasonic Instrument
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 35
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Block diagram: Ultrasonic InstrumentBlock diagram: Ultrasonic Instrument
amplifier
work piece
probe
horizontal
sweep
clock
pulser
IPBE
screen
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 36
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Sound reflection at a flawSound reflection at a flaw
Probe
Flaw Sound travel path
Work piece
s
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
delaminationplate 0 2 4 6 8 10
IP
F
BE
IP = Initial pulse
F = Flaw
BE = Backwall echo
Plate testingPlate testing
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
0 2 4 6 8 10
s
s
Wall thickness measurementWall thickness measurement
CorrosionM. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 1
Basic Basic Principles of Ultrasonic TestingPrinciples of Ultrasonic Testing
Basic Basic Principles ofPrinciples of
Ultrasonic TestingUltrasonic Testing
Theory andTheory and PracticePractice
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 39
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
0 2 4 6 8 10
Through transmission signal
1
2
1
2
T
T
R
R
Through transmission testingThrough transmission testing
Flaw
M. Berke - 02.05.2001 Krautkrämer, Hürth - Product Training 40
Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
0 20 40 60 80 100
s
aa'
d
x
a = s sinßa = s sinß
a' = a - xa' = a - x
d' = s cosßd' = s cosß
d = 2T - t'd = 2T - t'
s
Lack of fusion
Work piece with welding
Weld inspectionWeld inspection
F ß = probe angles = sound patha = surface distancea‘ = reduced surface distanced‘ = virtual depthd = actual depthT = material thickness
ß
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
Straight beam inspection techniques:Straight beam inspection techniques:Direct contact,
single element probe
Direct contact,
dual element probeFixed delay
Immersion testingThrough transmission
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Basic Principles of Ultrasonic TestingBasic Principles of Ultrasonic Testing
0 2 4 6 8 10 0 2 4 6 8 10
IE IEIP IP
BE BE
surface = sound entry
backwall
F
flaw
1
1
2
2
water delay
Immersion testingImmersion testing