The use of a line-focus transducer operating in pulse-echo mode to probe a liquid/solid interface is a new technique which has many engineering applications. To provide a theoretical basis for multi-echo analysis and interpretation, we use numerical integration to apply the time domain Green?s function of a liquid/solid interface. In general, a transducer must be considered to have an extended active surface. Two surface integrals of the basic Green?s function are required to model the line focus transducer. However, the numerical integrations can be reduced from four to two by invoking symmetry in two ways. The first is to assume that the cylindrical surface is infinitely long in the axial direction, and that all the field variables are independent of the axial coordinates. The second is to assume that the active element of the transducer is narrow in the axial direction, and therefore can be considered as a circular arc. With either simplification, the numerical integration can be carried out on a personal computer, though some computations may take hours to achieve the desired accuracy. Simulated waveforms of both models have been obtained. The arrivals of the various mode-converted transient wave fronts can be identified. Comparisons with experimental results are given.
Proceedings Title: Review of Progress in Quantitative Nondestructive Evaluation Edited by D.O. Thompson and D.E Chimenti, Plenum Press (New York)
Volume: Vol 15
Conference Dates: July 30-August 4, 1995
Conference Location: Seattle, USA
Pub Type: Conferences
Line-focus Microscopy, Transient ultrasonic wave, Ultrasonic transducer, Ultrasonics