10.14489/td.2016.11.pp.034-041

2016, 11 November

DOI: 10.14489/td.2016.11.pp.034-041

Rafikov R. H.
THE EFFECT OF THE DEPTH OF THE CORNER REFLECTORS OCCURRENCE ON THE CHARACTER OF ITS INDICATRIX OF SCATTERING
(pp. 34-41)

Abstract. It has been estimated the effect of the occurrence depth of the corner reflectors on the character of their indicatrices of scattering. As an indicatrix of scattering was considered temporal envelope of echo signals from a reflector, obtained by moving the transducer in the plane of incidence of the ultrasonic beam, followed by recalculation of the arrival time of the echo signal in the input angle of the corresponding point. Measurements were made on dihedral angles of the steel plates, thickness: 18, 45, 90, 135 and 180 mm. The diameter of used piezo plates of converters was 12 mm the operating frequency 2.5 MHz. It has been established the coincidence between maximum angles of the scattering indicatrix for the converters with nominal input angles 34, 36, 38 and 40° (prism angles close to the first critical angle for the pair of materials plexiglas-steel) that is explained by the features of the spread of creeping waves along the lower edge of the corner reflectors and by their predominant influence on the formation of detected echo signal. For the inverter with a nominal input angle 58° (angle close to supplementing angle 34 – 90°) observed maximum increase angle of indicatrix of scattering phase with 54° at a depth of 45 mm, up to 56° at the depth of 180 mm, what is explained by the transformation of the transverse wave in the creeping wave on the vertical face of the corner reflectors. It is advisable to take into account the obtained results in identification of located at different depths defects, by the character of their indicatrix of scattering.

Keywords: ultrasonic flaw detection, corner reflector, the occurrence depth, the scattering, the identification of defects, the transverse wave, the creeping wave.

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R. H. Rafikov (Moscow Technological University, Moscow, Russia) E-mail: Данный адрес e-mail защищен от спам-ботов, Вам необходимо включить Javascript для его просмотра.

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