CIVA Confirmation of Frequency Dependence of TOFD Lateral Wave

Pulse-duration (ring-time) of the TOFD (Time of Flight Diffraction) lateral wave has been assumed to be based on the nominal frequency of the probe. With the improved damping used for TOFD applications, these probes now have had their ring-time reduced to about 1.5 cycles. As a result of the short pulse duration, the bandwidth of these probes is greatly increased. However, assumptions based on the nominal frequency are only approximations. Underlying physics of beam divergence exacerbate these assumptions when considering the frequency content of the lateral wave. CIVA simulations are used to illustrate how using the nominal probe frequency underestimates the actual dead zone extent of the lateral wave.