Calculation of the directivity pattern of an obliqueentry probe
Abstract
Methods of ultrasonic flaw detection are analyzed to represent the field of obliqueentry probes. Expressions are derived on the basis of the Green integral transform, and diagrams are plotted in the refracting plane. Directivity patterns in the principal cross section are compared with standard formulas, demonstrating consistency on the radiation in the principal plane, and a method of replacing a circular source with a square source is proposed to simplify calculations. Results indicate that the asymmetry of the refracted field about the acoustic axis does not depend on the dimensions of the source or the frequency, and expressions describing the angular distribution of the field of longitudinal or transverse waves are recommended for engineering calculations of the directory obliqueentry probes. The error of replacing the real source by an imaginary source is also found to increase with the angle of refraction.
 Publication:

Defektoskopiia
 Pub Date:
 September 1981
 Bibcode:
 1981Defek..17...87G
 Keywords:

 Acoustic Propagation;
 Directivity;
 Nondestructive Tests;
 Shapes;
 Ultrasonic Flaw Detection;
 Green'S Functions;
 Imaging Techniques;
 Integral Transformations;
 Longitudinal Waves;
 Refraction;
 Instrumentation and Photography