An evaluation of single probe bulk-wave time-delay techniques in sizing cracks in steel

Locating the crack tip of a surface-breaking crack Part I. Line crack

“…( 3) has to satisfy a constraint condition max (& -a,, 3 4, -a,,) <2X, <min (dCl +a,,, de2 +a,,). (7) Geometrically, this constraint states that the .u-coordinate of the intersection point should be bounded by (d,, -a,i)/2 and (d~i + o,i)/2, i= 1,2, which are the smallest and largest x-coordinates, respectively, of two original half ellipses. In fact, in almost all of our numerical simulation, the quadratic equations of X, always have two (if any) real roots, but only one of them satisfies the constraint condition, Eq.…”

Four Transducer Ultrasonic Array for Detecting and Sizing Defects in Plate and Pipe Materials

“…The tip diffraction techniques [4,5,6] can be used to measure through-wall dimensions. Likewise, the diffraction signals can be and are detected by Transducers #2 and #3 (See Figure 1).…”

“…[1,2,3] Significant research has gone into the development and improvement of techniques and procedures for sizing of defects. Tip diffraction [4,5,6] and time of flight (TOF) [7,8] provide a substantial improvement over amplitude based sizing techniques. [9] However, for tight cracks or randomly oriented defects, the tip diffraction and TOF signals are often difficult to identify, thus reducing the reliability of these techniques.…”