Reference : UMR7031-SANGUE-027
Workplace : AIX EN PROVENCE
Date of publication : Tuesday, November 22, 2022
Type of Contract : FTC Scientist
Contract Period : 12 months
Expected date of employment : 1 February 2023
Proportion of work : Full time
Remuneration : Between 2889.51 et 3321.55 gross monthly according to experience
Desired level of education : PhD
Experience required : 1 to 4 years
The CEA is studying the various possibilities for non-destructive testing of the primary reactor vessel as well as the vessel internal structures in the context of Generation IV reactors, initially planned with liquid sodium cooling. The inspection of structures immersed in an opaque fluid could be carried out from outside the fluid medium, but this configuration presents a particular complexity because of the heterogeneous nature of the domain to be inspected (succession of solid/liquid interfaces). Among the ultrasonic inspection techniques, Lamb waves have been identified as a possible solution for an optimal propagation in such a system. The potential of time reversal has been recently studied in order to improve the control and detection of defects in one and two parallel immersed plates.
This recruitment is initiated within the framework of the joint laboratory MISTRAL (collaboration between the LMA and the CEA) and will be done in the continuity of PhD work carried out at the LMA on the "Generation and propagation of Lamb waves in multi-plate structures - Contribution of time reversal for the non-destructive testing by ultrasound of generation IV reactor vessels". This thesis followed numerous studies on the subject (PhD, internships and contracts), always in the framework of the Labcom MISTRAL, over a period of more than ten years..
The work will thus focus on two points:
- the continuation of the work on topological energy and the comparison of different solutions for defect imaging in parallel plates,
- a synthesis of all the work carried out by the LMA concerning the testing behind screen(s), allowing to draw conclusions about the industrial applicability.
- Study of the influence of the distance between the plates, as well as the geometry of the defect, on the topological energy results,
- Study of the potential and the limits on three plates, as well as on one plate at scale 1,
- Study of the possible contribution and/or limitation of the MPF (Match Field Processing) and DORT methods
- Valorization the work done
- Analysis and synthesis of all the previous works carried out by the LMA since the years 2000 concerning the problem of the control behind screens, in order to bring out the main conclusions, the general prospects and the remaining obstacles.
- PhD in Acoustics
- Deep knowledge of ultrasonic propagation, Lamb waves, time-reversal methods
- Rigor, autonomy, ability to synthesize, teamwork
The Mechanics and Acoustics Laboratory (LMA) is a mixed research unit of the CNRS (UMR 7031) whose supervisory bodies are Aix-Marseille University (AMU), CNRS and Centrale Marseille (ECM).
The LMA has a staff of about 110 people, including 70 permanent staff (researchers, teacher-researchers, engineers, assistant engineers and technicians) and about 30 doctoral students.
The laboratory develops original research that ranges from the understanding of phenomena to the development of systems with high technological or societal implications, including their design or the development of basic concepts and technologies.
The LMA has nationally and internationally recognized expertise in the fields of Solid Mechanics and Acoustics.
It is structured into three research teams: Materials and Structures, Sounds and Waves and Imagery where the person recruited will be assigned.
Constraints and risks
Travel to be expected between LMa and CEA Cadarache
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