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Acoustic measurements above a plate carrying Lamb waves

Acoustic measurements above a plate carrying Lamb waves

Category
Part of a book/report
Abstract
This article presents a set of acoustic measurements conducted on the Statoil funded Behind Casing Logging Set-Up, designed by SINTEF Petroleum Research to resemble an oil well casing. A set of simple simulations using COMSOL Multiphysics were also conducted and the results compared with the measurements. The experiments consists of measuring the pressure wave radiated of a set of Lamb waves propagating in a 3 mm thick steel plate, using the so called pitch-catch method. The Lamb waves were excited by a broadband piezoelectric immersion transducer with center frequency of 1 MHz. Through measurements and analysis the group velocity of the fastest mode in the plate was found to be 3138.5 m/s. Measuring the wave radiated into the water in a grid consisting of 8x33 measuring points, the spreading of the plate wave normal to the direction of propagation was investigated. Comparing the point where the amplitude had decreased 50 % relative to the amplitude measured at the axis pointing straight forward from the transducer shows that the wave spread out 3.2 mm after propagating 140 mm in the plate.
Language
English
Author(s)
Affiliation
  • Norwegian University of Science and Technology
  • SINTEF Digital / Connectivity Technologies and Platforms
  • Norwegian University of Science and Technology
Year
2016
Publisher
Norsk Fysisk Selskap
Book
Proceedings of the 39th Scandinavian Symposium on Physical Acoustics
ISBN
978-82-8123-016-3