Thesis Topic

Surface integrity prediction and in-situ monitoring in the context of milling operations on aerospace alloys
Prédiction de l’intégrité de surface et sa surveillance in-situ dans le cas de pièces usinées en alliage d’aluminium

Abstract

Airbus is, among other things, a world leader in the design and production of aluminum alloy aircraft structural parts. In this field, the machining process which consists in removing material with cutting tools is the most used by Airbus plants and its suppliers. The present and future challenges are: the increase in production rates, the level of quality requirements, and the competitiveness demanded on our current and future programs. This requires total control of our processes from the start of production, as well as the possibility of adapting our parameters on line to guarantee optimal production without non-conformity and without additional cost.
This thesis, whose subject is more global, deals with the reliability of machining parameters with the fatigue strength of parts through indirect measurements of surface integrity parameters. It is part of the "ambition Alu" project in finish milling of the 7075 aluminum alloy led by Airbus Operations. The objective is to improve the understanding of the impact of machining anomalies on the fatigue life of parts (especially the phenomenon of overheating), which can lead to premature failure of structural parts. In this context, the objective of this thesis is to adapt the implementation of machining to these issues, which can be summarized by the concept of factory 4.0, by developing the scientific and technological bricks necessary for the adaptation of the online process. One of the final objectives will be the implementation of a digital twin guaranteeing the conformity of the parts produced.
For aluminum alloys, it will be necessary to reconsider the choice of operating parameters of the machining process on the degradation of the surface integrity and mechanical characteristics, taking into account in particular the cases of overheating well known in grinding, to identify the representative industrial parameters and measurable in line, to propose the means of monitoring associated.
In parallel, a simulation model for the prediction of mechanical characteristics will be developed, based on an existing model for titanium alloys developed in the framework of the thesis of [Hamm2022]. Following a similar methodology, multiple benefits are expected, allowing both the prediction of the mechanical fatigue behavior of parts, for the use of the design office, as well as the monitoring of the conformity of the parts, usable by the methods and production.

Doctoral advisors

• Gérard POULACHON - Director,
• RITOU Mathieu,
• Frédéric ROSSI
• BIREMBAUX Hélène.

Partners

• Airbus
• LS2N

Project

N/A

Funding

• CIFRE

Start

3rd of April 2023

Expected end

3rd of April 2026