LaBoMaP News

Ivan Hamm's Phd defense

Publié le July 1, 2022 Mis à jour le July 1, 2022
Date(s)

le July 12, 2022

09:30 AM
Location (s)
Cluny / Amphitheater 2 /  Access Map

Ivan Hamm, PhD student at LaBoMaP, defends his CIFRE thesis with Airbus company entitled : "Quantitative study of the effect of process parameters on thermomechanical loading and surface integrity during Ti-6Al-4V finish milling"

JURY MEMBERS

  • Katia MOCELLIN, Associate Professor HDR, CEMEF, Mines Paris Tech / Examinatrice
  • Aldo ATTANASIO, Full Professor, Université de Brescia / Rapporteur
  • Vincent WAGNER, Associate Professor HDR, LGP, ENIT / Rapporteur
  • Gérard POULACHON, Full Professor, LaBoMaP, Arts et Métiers / Examinateur
  • Frédéric ROSSI, Associate Professor, LaBoMaP, Arts et Métiers / Examinateur
  • Nicolas MAURY, PhD Engineer, AIRBUS OPERATIONS SAS / Examinateur
  • Hélène BIREMBAUX, Assistant Professor, LaBoMaP, Arts et Métiers / Invitée

ABSTRACT

Aircraft structures, such as propulsion systems, are usually composed of metallic parts designed to tolerate high thermomechanical loads. These parts are obtained from blanks, which are then machined to final dimensions before being assembled. The machining process is thus a key step in the manufacturing cycle that must guarantee both dimensional requirements and mechanical properties.

In other words, it is essential to be able to ensure that the machined surface has all the characteristics, particularly the stress and metallurgical state, which will enable it to achieve its function over a predefined period according to its dimensions. Moreover, the evolution of production techniques and facilities, intended to increase the productivity and reliability of the process, leads to frequent modifications of the manufacturing process. It is therefore necessary, although sometimes difficult, to guarantee the quality and performance of the par ts produced while taking into account these updates in the manufacturing process. The interest of the surface integrity then takes all its sense on the aeronautical parts highly stressed under cyclic loadings. Indeed, the fatigue life is directly and strongly influenced by several characteristic of the surface integrity such as the surface topography, the residual stresses state and the metallurgical quality. The objective of the present work is to analyze the machining parameters of the finish milling operation of the Ti-6Al-4V titanium alloy, with the aim of making the inverse link between the surface integrity and the manufacturing process parameters.

This research is structured around the concept of Process Signature, whose approach consists in quantifying the thermal and mechanical load applied to the machined surface according to the process parameters. From these loadings, a thermomechanical modeling allows to define the temperature and displacement fields of the generated surface. Experimental tests are then carried out to establish the link between the thermomechanical loading case and the integrity of the surface obtained (residual stresses, microstructure, surface topography). This is the main purpose of the Process Signature concept, which links the loading case to the surface integrity. Once this link is established, it is then possible to develop an inverse model capable of predicting the effect of the milling process and its process parameters on the surface integrity obtained.

KEYWORDS

  • Process Signature
  • Inverse method
  • Surface integrity
  • Thermomechanical load
  • Ti-6Al-4V
  • Finish milling