Description du poste

CONTEXT: Friction-induced vibrations usually appear as an unwanted result of dry sliding. A typical example is squeal noise generated during braking in certain conditions. Even if the braking performances are not affected, squealing strongly incurs high maintenance costs, besides troubling passengers due to its high intensity in the audible frequency range. Physically, squeal or other similar noises represent a result of a giant amplification of noise which is, in turn, generated by a sequence of stick-slip-separation events occurring at the contact interface during dry sliding. In other words, instability should develop starting from a weak acoustic generation that accompanies friction. This instability can develop or not, depending on numerous conditions and factors such as contact micro-geometry or surface roughness, the presence or absence of the third body (lubricant, wear particles), applied external stresses, etc, acting at various spatial scales. Even if squealing frequencies can be predicted trough analytical or numerical approaches considering mode-coupling mechanism of instability or transient simulations, the conditions of squeal appearance are much harder to identify. One of main difficulties is related to coupling between the spatial scales to be included in the same numerical simulation.
INTERNSHIP OBJECTIVES: leaving aside the question of general condition determining the generation of friction-induced instabilities, we aim at a numerical demonstration of an elementary frictional contact system in which the instability can appear or not, depending on system’s parameters. To do that, we intend to couple existing models of instabilities developed in the LaMcube and frictional contact models for rough surfaces available at the IEMN.

Description de l'employeur

LaMcube
https://lamcube.univ-lille.fr/

IEMN
https://www.iemn.fr/

Descriptif du profil recherché

Required Skills:
• Strong background in numerical modeling (finite element analysis)
• Programming skills (Python, Fortran, etc.)
• Knowledge of tribology and dynamics is a plus

Conditions particulières d'exercice

Tasks to be completed:
• Literature review on the dynamic instability induced by dry friction.
• Numerical model development. The starting point is an unstable configuration (under flat and uniform friction surfaces assumption) which can be predicted using transient finite element simulation. In a second step, the contact imperfections are to be taken into account by using by an appropriate contact model.
• Analysis of the contact geometry impact on the dynamic response on the entire system and exemplar demonstration of friction-induced instabilities.

Langues

French, English

Informations complémentaires

We offer a standard internship salary of about 600 €
The candidate should de already based in France
Preferably, he or she looks for an internship necessary for completing Master 2 degree
This internship can be followed by a PhD thesis