PhD opportunities

Numerical simulation of an Additive Manufacturing process

Area of expertise Computational mechanics and Materials
Doctoral School SFA - Sciences Fondamentales et Appliquťes
Title Numerical simulation of an Additive Manufacturing process
Supervisor M. Michel BELLET
Co-supervisor M. Gildas GUILLEMOT
Contact
http://www.cemef.mines-paristech.fr/sections/formations/doctorats/pour-postuler/these-cemef-5024
Research unit Centre for material forming
Keywords Additive manufacturing, Numerical simulation, Energy transfer, Fluid mechanics, Solidification, Finite elements
Abstract CEMEF has developed during last years two approaches for numerical simulation of LBM process. A local approach at the scale of the incremental material deposition (Chen et al., 2017), and a global approach at the scale of the formed part (Zhang et al., 2017). The two approaches are developed using the C++ library CimLib of the laboratory and are based on 3D finite elements, with level set interface tracking and automatic adaptive remeshing. Indeed these approaches are required in order to develop and efficient tracking of bead shape evolution during the whole process when the heat source moves. All solvers are parallelized in order to save time during numerical simulations. The first approach will be extended in the frame of the present project.

The objective is to develop a model of energy transfer of the laser to the metal powder bed and the fusion zone (the surface of this latter domain is also curved due to vaporization effects). Moreover, Marangoni effect (tangential driving force at the liquid surface) will be taken into account. Its integration in CEMEF software is already effective but needs testing and validation in the context of metallic materials. Indeed, Marangoni effect is more intense than for ceramics which were studied before by Chen et al.. Moreover the viscosity of liquid metals is also known as smaller than the one encountered in ceramics leading to large changes in fluid flow evolutions. Partial vaporization of metal will be modelled by means of an additional normal stress along the liquid surface. Finally, interaction between metallic vapours and protection gases will be modelled, as this effect is found critical in practical manufacturing. Particularly, its consequences on the energy transfers will be investigated.

The PhD candidate will receive a formation and will develop his(her) personal skills in the domain of numerical mechanics applied to fluids mechanics and energy transfer. Following this PhD work, he(she) will exploit and develop his(her)capacities in R&D departments of different industries: spatial, aeronautics, metallurgy, energyÖ
Funding Convention CIFRE
Partnership
Starting date October 2nd 2017
Date of first publication May 31th 2017