Employer: Aix-Marseille University
Duration: 6 months
Start date: October 2020
Gross salary: 2 200 €/month to 3200 €/month depending on qualification and experience
Location: Laboratory of Mechanics and Acoustics of Marseille UMR7031, Aix-Marseille University
The laboratory of Mechanics and Acoustics of Marseille, CNRS, Aix-Marseille University, France is looking for a research engineer with a strong expertise in instrumentation developments and digital data acquisitions in the area of acoustic holography starting October 1st for a period of 6 months (the position is funded by AMIDEX, Aix-Marseille University).
Background and Research context
This research project in collaboration with researchers from the Laboratory of Mechanics and Acoustics (UMR 7031)/AMU Marseille, the Marine Physical Laboratory, University of California San Diego (USA) and the Naval Research Laboratory, Washington DC (USA) aims at developing acoustic methods for defect localization or complex structures characterization based on innovative holography acoustic devices.
A scientific challenge toward that objective comes first from the complexity of the inspected structure that has many degrees of freedom as opposed to the limited information provided by the few sensors that gives access to only a limited number of degrees of freedom of the structure. Secondly, another major limitation for characterizing elastic structure from acoustic data comes from structure interactions with the surrounding environment that impacts the data and makes it difficult to decorrelate/separate intrinsic elastic object response/signature from surrounding environment contribution (sensor holder, fluctuation of the environment, boundaries, mechanical properties, …).
One approach was developed recently for addressing those two challenges for estimating the intrinsic or in vacuo response (= structural impedance/admittance) of an elastic target based on the impedance matrices formalism  and on the noise correlation method  for getting pressure and velocity information. In the frequency range of few kHz [1 kHz -10 kHz], the approach was demonstrated numerically on a 2 D cylinder immersed in water  and experimentally on a spherical shell in air in a non-anechoic environment with microphones and accelerometers at the surface . In order to minimize coupling effect between sensors, a method based on a contactless dual array of microphones has recently been developed for computing the structural impedance and further compute far field bi-static scattering . The experimental demonstration of the approach is currently in progress and a versatile large dual array of mems microphone is currently under development .
Plan of work
In collaboration with researchers from LMA, MPL and NRL, the successful candidate will further develop the acoustic holography experimental set-up to allow simultaneous acquisition and processing of large amount of digital data measured with the dual array of digital mems microphones (500 sensors).
The research engineer activities will then be focused on the following tasks:
Please send your application including a CV, a cover letter and the names/contact information of 1-2 referees who can provide a detailed account of your accomplishments and abilities to:
Dr. Sandrine Rakotonarivo: firstname.lastname@example.org
The position will be open until filled.
 Yu. I. Bobrovnitskii, “Impedance theory of sound scattering: General relations,” Acoust. Phys. 52(5), 513–517 (2006).
 O. I. Lobkis, R. L. Weaver, “On the emergence of the Green’s function in the correlations of a diffuse field”, Journal of Acoustical Society of America, vol. 110, 3011 – 3017 (2001)
 S. T. Rakotonarivo, W. A. Kuperman and E. Williams, « Prediction of a Body’s Structural Impedance and Scattering Properties using Correlation of Random Noise », Journal of Acoustical Society of America, vol. 134, 4401 – 4411 (2013)
 E. Williams, J. D. Tippmann, S. T. Rakotonarivo, W. Kuperman, Z. Waters, P. Roux, « Experimental estimation of in vacuo structural admittance using random sources in a non-anechoic room », Journal of Acoustical Society of America, vol. 142, 103 – 109 (2017)
 “Bistatic scattering of an elastic object using the structural admittance and noise-based holographic measurements”, accepted to Journal of Acoustical Society of America (2020)
 Jit Sarkar, Sandrine T. Rakotonarivo, Simone Sternini, Alexis Bottero, Earl G. Williams, Jeffrey Dwayne Tippmann, and William A. Kuperman, “Holographic array for determining structural acoustic properties”, UACE Crete, (2019)Meer informatie
|Titel||Research engineer position for developing acoustic holography experiments at the Laboratory of Mechanics and Acoustics (LMA, Marseille, France)|
|Job location||Jardin du Pharo 58, bd Charles Livon, 13284 Marseille|
|Gepubliceerd||augustus 3, 2020|
|Vakgebieden||Geluidsleer (Akoestiek),   Experimentele fysica,   Akoestische techniek,   Mechanica,   Signaalverwerking,   Electronica  |