Context:

Although non-destructive control using piezoelectric sensors (PZT) has permanently redefined the way aircraft equipment is maintained, its heavy deployment now limits its implementation under operational conditions. The problem is not the PZT’s, which are small enough to be integrated into the structure, but the many wired connections that make any deployment cumbersome and complex.

In these conditions, wireless technology would allow in the medium term to eliminate wired connections while maintaining (i) the pilotability of PZT transmission and reception and (ii) the ability to measure the acoustic response of excited structures. This new technology for monitoring structures in real time would allow for example systematic monitoring in the context of the reusable space vehicle.

Today the specific application of Ariane 6 screwing tension monitoring for critical assemblies is done with a technique involving temporal US acousto-elastic method which allows to support development and qualification. On the other hand, an explorative work has been done recently with IMS to show to potential to adapt this method to wireless communication technique [1]. First results show that a frequency domain characterization technique yields improved dynamic range and potential for contact-less measurement (wireless implementation) while using the same acousto-elastic phenomenon.

Overall objective

As part of the measurement of screw tightening torque, the main objective of this thesis project is the realization of a pre-industrial demonstrator (TRL 5-6) of «wireless Structural Health Monitoring» system. Meaning the two sub technical objectives: understanding of measurement limits and developing the adapted method for extracting acousto-elastioc features and communication solutions.

Scientific and technical goals/locks

The wireless Structural Health Monitoring technology will rely on the expertise in non-destructive testing and radio frequency electronics of ArianeGroup and the University of Bordeaux to achieve the following goals:

• Wireless energy transfer & electromagnetic-to-acoustic conversion device: The electrical power supply to the piezoelectric ultrasonic transducer that will excite the structure to be analyzed will be done by magnetic resonant coupling that will allow remote and non-contact operation. The resonant magneto-acoustic “relay” device will also be able to convert the information-carrying acoustic wave into a magnetic field or radio frequency wave radiated at a greater distance. Within these two challenges, the thesis project will focus on maximizing wireless transfer distances and minimizing the size of devices to facilitate their integration.

• Structural Health Monitoring (SHM) and Non-destructive testing (NDT) by measurements of acoustic flight times in the spectral domain: unfortunately, the power transmission by magnetic resonant coupling is not compatible with the «pulse-echo» method (because the bandwidth of this signal is not compatible with the narrow band of the resonators used for near field magnetic coupling) generally used by the SHM/NDT community. We therefore propose to implement a spectral & narrow band scanning method recently demonstrated by the two partners [1-2], and to develop a processing technique which will allow the extraction of physical parameters under operational conditions. This solution also has a strong signal/noise ratio potential which could also allow on-board operation

References: 

[1] A Kuakuvi, C Dejous, D Barnoncel, S Hemour, : Structural Health Monitoring of Reusable Launch System Using Endovibrator-Type Wireless Sensors, 2024 54th European Microwave Conference (EuMC), 292-295, 2024

[2] D Barnoncel, S Hemour, Méthode de mesure fréquentielle sans-fil de la tension de serrage d’une vis d’assemblage d’un lanceur spatial

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For more Information about the topics and the co-financial partner (found by the lab!); contact Directeur de thèse - simon.hemour@u-bordeaux.fr

Then, prepare a resume, a recent transcript and a reference letter from your M2 supervisor/ engineering school director and you will be ready to apply online before March 13th, 2026 Midnight Paris time!