Basic principles us_presentation
- 1. Basic Principles of Ultrasonic Testing Basic Principles of Ultrasonic Testing Theory and Practice Krautkramer NDT Ultrasonic Systems
- 2. Basic Principles of Ultrasonic Testing Examples of oscillation ball on pendulum rotating a spring earth Krautkramer NDT Ultrasonic Systems
- 3. Basic Principles of Ultrasonic Testing Pulse The ball starts to oscillate as soon as it is pushed Krautkramer NDT Ultrasonic Systems
- 4. Basic Principles of Ultrasonic Testing Oscillation Krautkramer NDT Ultrasonic Systems
- 5. Basic Principles of Ultrasonic Testing Movement of the ball over time Krautkramer NDT Ultrasonic Systems
- 6. Basic Principles of Ultrasonic Testing Frequency Time From the duration of one oscillation One full T the frequency f (number of oscillation T oscillations per second) is calculated: 1 f = T Krautkramer NDT Ultrasonic Systems
- 7. Basic Principles of Ultrasonic Testing The actual displacement a is termed as: a = A sin ϕ a Time 0 90 180 270 360 Phase Krautkramer NDT Ultrasonic Systems
- 8. Basic Principles of Ultrasonic Testing Spectrum of sound Frequency range Hz Description Example 0 - 20 Infrasound Earth quake 20 - 20.000 Audible sound Speech, music > 20.000 Ultrasound Bat, Quartz crystal Krautkramer NDT Ultrasonic Systems
- 9. Basic Principles of Ultrasonic Testing Atomic structures gas liquid solid • low density • medium density • high density • weak bonding forces • medium bonding • strong bonding forces forces • crystallographic structure Krautkramer NDT Ultrasonic Systems
- 10. Basic Principles of Ultrasonic Testing Understanding wave propagation: Ball = atom Spring = elastic bonding force Krautkramer NDT Ultrasonic Systems
- 11. Basic Principles of Ultrasonic Testing star t of o sc T illat ion distance travelled Krautkramer NDT Ultrasonic Systems
- 12. Basic Principles of Ultrasonic Testing During one oscillation T the wave T front propagates by the distance λ: Distance travelled From this we derive: or Wave equation c= λ c = λf T Krautkramer NDT Ultrasonic Systems
- 13. Basic Principles of Ultrasonic Testing Sound propagation Longitudinal wave Direction of propagation Direction of oscillation Krautkramer NDT Ultrasonic Systems
- 14. Basic Principles of Ultrasonic Testing Sound propagation Transverse wave Direction of propagation Direction of oscillation Krautkramer NDT Ultrasonic Systems
- 15. Basic Principles of Ultrasonic Testing 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 330 m/s Water 1480 m/s Steel, long 5920 m/s Steel, trans 3250 m/s Krautkramer NDT Ultrasonic Systems
- 16. Basic Principles of Ultrasonic Testing 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
- 17. Basic Principles of Ultrasonic Testing Behaviour at an interface Medium 1 Medium 2 Incoming wave Transmitted wave Reflected wave Interface Krautkramer NDT Ultrasonic Systems
- 18. Basic Principles of Ultrasonic Testing Reflection + Transmission: Perspex - Steel 1,87 Incoming wave 1,0 Transmitted wave 0,87 Reflected wave Perspex Steel Krautkramer NDT Ultrasonic Systems
- 19. Basic Principles of Ultrasonic Testing Reflection + Transmission: Steel - Perspex Incoming wave Transmitted wave 1,0 0,13 -0,87 Reflected wave Perspex Steel Krautkramer NDT Ultrasonic Systems
- 20. Basic Principles of Ultrasonic Testing Amplitude of sound transmissions: Water - Steel Copper - Steel Steel - Air • Strong reflection • No reflection • Strong reflection • Double transmission • Single transmission with inverted phase • No transmission Krautkramer NDT Ultrasonic Systems
- 21. Basic Principles of Ultrasonic Testing Piezoelectric Effect + Battery Piezoelectrical Crystal (Quartz) Krautkramer NDT Ultrasonic Systems
- 22. Basic Principles of Ultrasonic Testing Piezoelectric Effect + The crystal gets thicker, due to a distortion of the crystal lattice Krautkramer NDT Ultrasonic Systems
- 23. Basic Principles of Ultrasonic Testing Piezoelectric Effect + The effect inverses with polarity change Krautkramer NDT Ultrasonic Systems
- 24. Basic Principles of Ultrasonic Testing Piezoelectric Effect Sound wave with frequency f U(f) An alternating voltage generates crystal oscillations at the frequency f Krautkramer NDT Ultrasonic Systems
- 25. Basic Principles of Ultrasonic Testing Piezoelectric Effect Short pulse ( < 1 µs ) A short voltage pulse generates an oscillation at the crystal‘s resonant frequency f0 Krautkramer NDT Ultrasonic Systems
- 26. Basic Principles of Ultrasonic Testing 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 crystal Ultrasonic wave energy Krautkramer NDT Ultrasonic Systems
- 27. Basic Principles of Ultrasonic Testing Ultrasonic Probes socket Delay / protecting face crystal Electrical matching Damping Cable Straight beam probe TR-probe Angle beam probe Krautkramer NDT Ultrasonic Systems
- 28. Basic Principles of Ultrasonic Testing RF signal (short) 100 ns Krautkramer NDT Ultrasonic Systems
- 29. Basic Principles of Ultrasonic Testing RF signal (medium) Krautkramer NDT Ultrasonic Systems
- 30. Basic Principles of Ultrasonic Testing Sound field Crystal Focus Angle of divergence Accoustical axis γ6 D0 N Near field Far field Krautkramer NDT Ultrasonic Systems
- 31. Basic Principles of Ultrasonic Testing Ultrasonic Instrument 0 2 4 6 8 10 Krautkramer NDT Ultrasonic Systems
- 32. Basic Principles of Ultrasonic Testing Ultrasonic Instrument - + Uh 0 2 4 6 8 10 Krautkramer NDT Ultrasonic Systems
- 33. Basic Principles of Ultrasonic Testing Ultrasonic Instrument + - Uh 0 2 4 6 8 10 Krautkramer NDT Ultrasonic Systems
- 34. Basic Principles of Ultrasonic Testing Ultrasonic Instrument + Uv - + - Uh 0 2 4 6 8 10 Krautkramer NDT Ultrasonic Systems
- 35. Basic Principles of Ultrasonic Testing Block diagram: Ultrasonic Instrument amplifier screen IP horizontal BE sweep clock pulser probe work piece Krautkramer NDT Ultrasonic Systems
- 36. Basic Principles of Ultrasonic Testing Sound reflection at a flaw s Probe Sound travel path Flaw Work piece Krautkramer NDT Ultrasonic Systems
- 37. Basic Principles of Ultrasonic Testing Plate testing IP BE F delamination 0 2 4 6 8 10 plate IP = Initial pulse F = Flaw BE = Backwall echo Krautkramer NDT Ultrasonic Systems
- 38. Basic Principles of Ultrasonic Testing Wall thickness measurement s s Corrosion 0 2 4 6 8 10 Krautkramer NDT Ultrasonic Systems
- 39. Basic Principles of Ultrasonic Testing Through transmission testing Through transmission signal 1 T R 1 2 T R 2 0 2 4 6 8 10 Flaw Krautkramer NDT Ultrasonic Systems
- 40. Basic Principles of Ultrasonic Testing Weld inspection a = s sinß F a' = a - x ß = probe angle s s = sound path a = surface distance d' = s cosß a‘ = reduced surface distance d‘ = virtual depth 0 20 40 60 80 100 d = 2T - t' d = actual depth T = material thickness a x a' ß d Lack of fusion Work piece with welding s Krautkramer NDT Ultrasonic Systems
- 41. Basic Principles of Ultrasonic Testing Straight beam inspection techniques: Direct contact, Direct contact, Fixed delay single element probe dual element probe Through transmission Immersion testing Krautkramer NDT Ultrasonic Systems
- 42. Basic Principles of Ultrasonic Testing Immersion testing 1 2 surface = water delay sound entry backwall flaw IP 1 IP IE IE 2 BE BE F 0 2 4 6 8 10 0 2 4 6 8 10 Krautkramer NDT Ultrasonic Systems