In the industrial context of pressurized water reactors (PWR) within the French nuclear power plant fleet, the internal components of PWRs susceptible to wear are subject to special monitoring. Faced with these challenges, EDF and CEA aim to enhance the understanding and prediction of wear phenomena, not only to optimize maintenance operations and improve component design but also to optimize research and development efforts while ensuring the reliability of the obtained results.

Among the technical and scientific objectives set within the framework of their collaboration since 2014, the development and improvement of wear testing equipment and associated digital twins is of particular importance, with the modeling of wear testing machines considered a priority.

The state of the art in the field of nonlinear dynamics modeling of mechanical systems with clearances has led recent research at CEA towards the modeling of vibratory wear testing machines, particularly the MUSE* tribometer and its two electromagnetic actuators. Encouraging initial results have been obtained through the modeling of a single actuator. Identifying the different vibratory regimes involving impact and friction and the bifurcations of this machine is of crucial importance for understanding the testing apparatus. This knowledge will enable more precise specifications for wear tests and better control of the necessary contact conditions for studying the phenomenon.

The thesis work will involve modeling the nonlinear dynamics of both types of vibratory wear testing machines at CEA. The numerical developments to be carried out in Python and using the finite element code Cast3M (http://www-cast3m.cea.fr/) will complement the existing computational tools and will be proposed to determine a comprehensive map of vibratory regimes with impact and friction, as well as bifurcations. The results of the simulations will be compared to those from experiments conducted within the scope of this thesis to validate and improve the proposed computational models.

Graduates of top engineering schools or holders of a Master's degree (M2), the candidate should have skills in structural and materials mechanics, and in numerical simulation.

At the end of the thesis, the student's experience can be put to good use in research positions in industry (nuclear, automotive, rail, aeronautics, medical, etc.), and in the academic network.

An M2 internship on the same subject is offered prior to the thesis. Applying for this internship is not a requirement for the thesis, but it could be an asset for the student.

* : Moyen d’essais d’USure en environnement REP of the CEA-DES/ISAS/DM2S/SEMT Paris-Saclay RESEDA’s platform.