Analysis of surface defects using the ultrasonic Rayleigh surface wave : A step towards an accurate, fast and reliable NDT technique for surface defects

ISBN-13: 9783639174601 / Niemiecki / Miękka / 2009 / 140 str.

Fan Yichao

Opis

Surface defects, such as gauge corner cracking on therailway track can be a difficult class of defects forexisting on-line non-destructive testing techniquesto detect and size accurately at high speed. Thereare economic and safety benefits to have an accurate,fast and reliable NDT technique to detect suchdefects. The EMAT pitch-catch ultrasonic testingtechnique, using the Rayleigh surface wave, has beenshown to be able to detect and size surface defects.The pitch-catch geometry also allows this techniqueto be used at high speed on-line NDT applications.This research has also identified a number ofultrasonic signal features that arise from theinteraction between the surface wave and surfacedefects, such as: the non-linear laser generationeffect, the signal enhancement effect, and theRayleigh wave recovery effects. They can havepotential NDT applications for detecting and sizingsurface defects. The ferrite enhanced EMAT is able togenerate similar ultrasonic surface waves to theconventional EMATs, in some cases, with highergeneration efficiency and better stand-offperformance. This research should be of interest tothose in ultrasonic NDT community.

O autorze

Charley (Y) Fan is a Post-doc researcher at the University of
Warwick, specialised in non-contact ultrasonic and eddy current
online NDT techniques. Research interests also include finite
element simulations and digital signal processing.