Shear wave ultrasonic transducers for contact mode testing are commercially available. These packaged transducers usually contain a circular piezoelectric element and the mounting is such that the polarization direction of the shear vibration is defined by a line passing through the center of the transducer and the electrical connector. For measure ments in isotropic materials, the polarization direction is not important. For quantitative shear wave measurements in anisotropic materials such as composites1–3, it is important to know the polarization direction of the transducer with a good precision. Unfortunately, commercial shear wave transducers are usually not very accurate in their mounting; it is not uncommon to have +/- 10° of error in their polarization direction and much greater errors have also been encountered.
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