NON-DESTRUCTIVE TEST OF A SURFACE DEFECT ON A STEEL BAR BASED ON ULTRASONIC GUIDED WAVE TECHNIQUES

The multi-modes and disperse characteristics of guided waves in steel bar are investigated theoretically and experimentally. With experiments, the phenomena of 揕-Wave Precursor?is verified and analyzed. Meanwhile, an artificial surface defect of a 2320mm steel bar is detected. Results show that it is feasible for detecting the defects on a steel bar surface using L(0,1) mode of ultrasonic guided waves for a given special frequency.