Ultrasonic transducer characterization and transducer beam modeling for applications in nondestructive evaluation

Abstract

A new and computationally efficient method is developed for characterizing a spherically focused, ultrasonic transducer (and its accompanying test system). Procedures for determining the probe's effective radius, effective focal length, and system efficiency factor are described. Predicted responses that make use of these effective parameters are shown to correspond very well to measured responses for a number of different transducers.

Evolution of Qnde’s Core Interdisciplinary Science and Engineering Base

“…9. The Gauss-Hermite [7,8,9], the multi-Gaussian [10,11], and the boundary diffraction models [12,13,14] are all paraxial models. Other models have been developed that may be more detailed but also more computationally intensive than these [15,16,17,18,19,20,21].…”

The Wavefield of an Ultrasonic Angle Beam Shear Wave Transducer: An Elastodynamic Approach

“…At this point, the incident wavefields of the elastodynamic model could be evaluated through direct numerical integration procedures, but this type of evaluation would be computationally costly to do because of the two dimensional nature of the integration. By using the edge element technique discussed in earlier papers [3,7], the post stationary phaseform ofthe wavefields can be significantly simplified (numerically) by reducing the order of integration from 2-D to 1-D, thus saving computational time while retaining the same Ievel of accuracy as the more numerically intensive approaches. A paraxial assumption could also be made at this juncture [2], but in this case, a certain amount of accuracy would be lost in the very nearfield areas of the wavefield.…”

“…As mentioned earlier, the a;ß superscripts correspond to a refracted wave oftype a (a=P,SV) due to an incident wave oftype ß (ß=P,SV). As was shown in [7], edge elements can also be applied to this fluid-solid planar interface problem, where the incident displacements in the second medium are (2) Note that the only difference between the fluid-solid interface model shown above and the incident P-wave contributions of the solid-solid interface model is the directivity function, K/O;P), in the solid-solid model. In the model comparisons section, we will briefly compare the incident P-wave components of both models and exarnine the effect of the directivity function in the elastodynarnic (solid-solid interface) model.…”

“…Explicit expressions for these transmission coefficients are given in [7]. The planar interface also allows the total incident shear wave in the frrst medium to be decomposed into two orthogonal parts, SV and SH.…”

“…However, in this elastodynamic model, these spherical wave sources are modified by directivity functions, KP(O(P), K, ( 8(,) , and polarization vectors, d P and d s, for the compressive and shear wave terms, respectively. The compressive and shear wave directivity functions are explicitly stated in [7], and depend only on the wedge material's wavespeeds, c 1 P, c~> , and the incident …”