2019_programme: HOLOGRAPHIC ARRAY FOR DETERMINING STRUCTURAL ACOUSTIC PROPERTIES
- Session: 10. Design of new experimental facilities to address future problems in underwater acoustics
Organiser(s): Sessarego Jean-Pierre, Fattaccioli Dominique, Real Gaultier
- Lecture: HOLOGRAPHIC ARRAY FOR DETERMINING STRUCTURAL ACOUSTIC PROPERTIES [invited]
Paper ID: 997
Author(s): Sarkar Jit, Rakotonarivo Sandrine T., Sternini Simone, Bottero Alexis, Williams Earl G., Tippmann Jeffery Dwayne, Kuperman William A.
Presenter: Kuperman William A.
Presentation type: oral
Abstract: It has already been shown that the scattering properties of an arbitrary object in an external medium can be determined by three quantities: The structural impedance matrix, Zs, the input impedance matrix Zi, and the radiation impedance matrix, Zr. Only Zs is dependent on the specific, possibly unknown and complicated internal structure of the object; the other two are only dependent on the surface shape of the object and the external medium so they can be routinely computed. We have constructed a laboratory facility to measure the structural impedance of an object by placing it in an external, diffuse noise field. The measurements are made using an array of a double layer of MEMS microphones placed in the near field of the object; the array is embedded in a skeletal structure which surrounds the object. This array structure is programmatically generated from a 3D scan of the object, and constructed using a large 3D printer. Cross correlating the MEMS acoustic data together with holographic signal processing yields the structural impedance, with the large matrix-matrix calculations being accelerated on a GPU computing platform. These results combined with the other computed impedances provides the scattering properties of the object when placed (loaded) in an external medium. The details of the experimental setup are explained and preliminary results are presented.
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- Corresponding author: Dr Sarkar Bikramjit
Affiliation: Scripps Institution of Oceanography, UC San Diego
Country: United States