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Krautkramer NDT Ultrasonic Systems
Basic Principles of Ultrasonic Testing Theory and Practice Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Examples of oscillation ball on a spring pendulum rotating earth Krautkramer NDT Ultrasonic Systems
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Pulse The ball starts to oscillate as soon as it is pushed
Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Oscillation Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Movement of the ball over time Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Frequency Time From the duration of one oscillation T the frequency f (number of oscillations per second) is calculated: One full oscillation T Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
The actual displacement a is termed as: a Time 90 180 270 360 Phase Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Spectrum of sound Frequency range Hz Description Example 0 - 20 Infrasound Earth quake Audible sound Speech, music > Ultrasound Bat, Quartz crystal Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Atomic structures gas liquid solid low density weak bonding forces medium density medium bonding forces high density strong bonding forces crystallographic structure Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Understanding wave propagation: Ball = atom Spring = elastic bonding force Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
start of oscillation T distance travelled Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
During one oscillation T the wave front propagates by the distance : T Distance travelled From this we derive: Wave equation or Krautkramer NDT Ultrasonic Systems
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Sound propagation Longitudinal wave Direction of propagation
Direction of oscillation Krautkramer NDT Ultrasonic Systems
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Direction of propagation
Sound propagation Transverse wave Direction of oscillation Direction of propagation Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
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. Air Water Steel, long Steel, trans 330 m/s 1480 m/s 3250 m/s 5920 m/s Krautkramer NDT Ultrasonic Systems
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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: Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Behaviour at an interface Medium 1 Medium 2 Incoming wave Transmitted wave Reflected wave Interface Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Reflection + Transmission: Perspex - Steel 1,87 Incoming wave 1,0 Transmitted wave 0,87 Reflected wave Perspex Steel Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Reflection + Transmission: Steel - Perspex Incoming wave Transmitted wave 1,0 0,13 -0,87 Reflected wave Steel Perspex Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Amplitude of sound transmissions: Water - Steel Copper - Steel Steel - Air Strong reflection Double transmission No reflection Single transmission Strong reflection with inverted phase No transmission Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Piezoelectric Effect + Battery Piezoelectrical Crystal (Quartz) Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Piezoelectric Effect + The crystal gets thicker, due to a distortion of the crystal lattice Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Piezoelectric Effect + The effect inverses with polarity change Krautkramer NDT Ultrasonic Systems
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U(f) Piezoelectric Effect Sound wave with frequency f
An alternating voltage generates crystal oscillations at the frequency f Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Piezoelectric Effect Short pulse ( < 1 µs ) A short voltage pulse generates an oscillation at the crystal‘s resonant frequency f0 Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Reception of ultrasonic waves A sound wave hitting a piezoelectric crystal, induces crystal vibration which then causes electrical voltages at the crystal surfaces. Electrical energy Piezoelectrical crystal Ultrasonic wave Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Ultrasonic Probes socket crystal Damping Delay / protecting face Electrical matching Cable Straight beam probe Angle beam probe TR-probe Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
RF signal (short) 100 ns Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
RF signal (medium) Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Sound field N Near field Far field Focus Angle of divergence Crystal Accoustical axis D0 6 Krautkramer NDT Ultrasonic Systems
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Ultrasonic Instrument
2 4 8 10 6 Krautkramer NDT Ultrasonic Systems
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Ultrasonic Instrument
2 4 8 10 6 + - U h Krautkramer NDT Ultrasonic Systems
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Ultrasonic Instrument
2 4 8 10 6 + - U h Krautkramer NDT Ultrasonic Systems
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Ultrasonic Instrument
2 4 8 10 6 + - U h v Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Block diagram: Ultrasonic Instrument amplifier work piece probe horizontal sweep clock pulser IP BE screen Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Sound reflection at a flaw s Probe Sound travel path Flaw Work piece Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Plate testing delamination plate 2 4 6 8 10 IP F BE IP = Initial pulse F = Flaw BE = Backwall echo Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Wall thickness measurement s s Corrosion 2 4 6 8 10 Krautkramer NDT Ultrasonic Systems
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Through transmission testing
2 4 6 8 10 Through transmission signal 1 T R Flaw Krautkramer NDT Ultrasonic Systems
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Work piece with welding
Weld inspection 20 40 60 80 100 s a a' d x a = s sinß a' = a - x d' = s cosß d = 2T - t' Lack of fusion Work piece with welding F ß = probe angle s = sound path a = surface distance a‘ = reduced surface distance d‘ = virtual depth d = actual depth T = material thickness ß Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Straight beam inspection techniques: Direct contact, single element probe dual element probe Fixed delay Immersion testing Through transmission Krautkramer NDT Ultrasonic Systems
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Krautkramer NDT Ultrasonic Systems
Immersion testing 1 2 surface = sound entry water delay backwall flaw 2 4 6 8 10 IE IP BE F 1 Krautkramer NDT Ultrasonic Systems
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