Your application must include a recommendation letter from your Ph.D. supervisor, a detailed CV including university education and work experience, a list of publications, a 2-page description of the work undertaken during the course of your PhD.

For more Information, contact : Directeur de Recherche - michel.castaings@u-bordeaux.fr

Submit the complete application online (Apply) before March 13th, 2026 Midnight Paris time

===================

In the context of space flights, the lightening of the materials used is essential. The reduction of the weight of the liquid ergol tanks (involving cryogenic temperatures) is a goal allowing a gain in the performance of the structures. This may involve replacing traditional titanium liners with polymer liner solutions. The mass gain could be very substantial but such a structure presents a risk of microcracks, which must be controlled in a simple, fast and efficient. SHM (Structural Health Monitoring), based on the propagation of guided ultrasound waves, is a promising technique for the following reasons:

- the control system is permanently installed (so no disassembly of the parts) and requires only the activation of a command to start the inspection process, which is therefore simple and fast;

- well chosen (type of mode, frequency), ultrasonic guided waves are sensitive to the micro cracking of the material and thus provide the desired efficiency.

However, the MMS only controls the restricted area where the sensors are installed. It may therefore be advisable, when the SHM procedure has detected a localized microcracks of the material, to disassemble the part for a full inspection. The activities presented in the document are therefore divided into two parts:

- the first is focused on lifting the latches necessary to establish an SHM-type solution, suitable for monitoring the health of cylindrical composite parts representative of a light tank (part not disassembled and localized inspection);

- the second proposes to develop a procedure for a non-contact and automated control of this type of part (disassembled part and global inspection).

I. SHM with ultrasound for composites cylindrical parts

This section deals with the study of the propagation of guided ultrasonic waves (the basis of MMS by ultrasound) along a cylindrical composite part and in particular the demonstration of the potential of these waves to detect, see quantifying, the microcracks of the material. A numerical simulation campaign will first have to be conducted to identify the modes likely to propagate along the part, and to identify those most sensitive to a drop of 10 to 20% of the elasticity modules of the material (Previous studies have shown that the microcracks of carbon-epoxy composites results in such a reduction in material stiffness). Once the sensitive mode(s) has been identified, an experimental implementation will be carried out to generate and detect this mode(s), measure their characteristic, speed and/or attenuation, carrier(s) information on the condition of the material.

This sensitivity study will be conducted for the composite part alone and also for the composite with internal polymer coating, to determine whether or not the presence of this coating changes the nature of the guided modes and their susceptibility to composite cracking.

II. NDT with ultrasound for composites cylindrical parts

This section focuses on the development of an automated, non-contact NDT procedure for the entire cylindrical composite part (without or with internal coating). This process requires disassembly of the part and is therefore aimed, more particularly, at parts for which SHM-type monitoring would have revealed a localized micro-cracked area. It consists in checking whether this microcracks concerns the whole material.

The process also makes it possible to detect, image and quantify defects (delaminations, inserts, porous areas) or damages (impacted areas). Its application can therefore prove useful at the end of the manufacturing of the composite part, in order to verify its conformity before it is put into service, or during its use.

For all these studies the support of ArianeGroup is proposed for:

- Define the targets and applications and guide the choice of operating methods of the proposed methods.

- Provide specimens representative of targets and applications needed for experimental activities in a healthy, micro-fissured state.

- Provide material support for the conduct of experimental activities.