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Michel BELLET

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Professor
Head of research group "Thermo-Mechanics Plasticity" at Cemef
Co-responsible of the Specialty "Materials Science & Engineering" at MINES ParisTech


email :
Tel. +33 (0)4 93 95 74 61
Room : IE 214


List of publications (pdf)

Born in 1960,
  • Civil Engineer of Ecole des Mines de Paris, specialty "Materials Science and Engineering", 1982
  • R&D Engineer in steel industry, Usinor group (1983-1984)
  • Ph.D. in Materials Science and Engineering, Ecole des Mines de Paris, 1988: Numerical Finite element simulation of sheet forming, with application to the superplastic forming process
  • Head of  "Thermo-Mechanics and Plasticity" Research Group in Cemef, since 1990
  • Co-responsible of the Specialty "Materials Science & Engineering" at Mines-ParisTech, since 2007


Research areas


Most of my researches aim at the numerical modelling of processes involving solidification of metallic alloys: ingot and shape casting, continuous casting, welding. They also encompass the development of experimental techniques with an objective of validation of the developed models and of background support for the ideas guiding models definition.
The objective consists in predicting distortions, stresses, composition heterogeneities, distribution of metallurgical phases, defects (cracks, porosities). This is why we address the modelling of the various interactions between heat transfer, fluid flow, solid mechanics, solid/liquid phase changes, phase changes in the solid state. We focus especially our interest on the modelling of the thermomechanics of mushy zones (liquid-solid): two-phase liquid-solid flows with fluid-structure interaction, coupled phenomena such as segregation of chemical species, at different scales: micro, meso, macro. These researches are conducted in collaboration with other research groups of Cemef (MSR, SP2, CIM), with Transvalor company, and with industrial partners.

Another research area is the numerical modelling of metal powder compaction processes: cold and hot compaction, and more recently, simulation of hot compaction at the mesoscale and of the spark plasma sintering process (Joule assisted sintering process).

Up to a recent period, a part of my activities dealt with the modelling of polymer processing: thermoforming, extrusion – blow moulding, injection stretch – blow moulding.

22 Ph.D. theses have been defended under my supervision, or my co-supervision (8 ongoing theses),
19 internships of "Advanced Master" (1 ongoing)
20 internships in last year of undergraduate formation (1 ongoing)


Scientific Topics


Numerical Modeling :
  • FEM formulations for various constitutive equations (elasto-(visco)plasticity, compressible elasto-(visco)plasticity)
  • Thermomechanics of solids and fluids
  • Error estimation for adaptive anisotropic remeshing
  • Arbitrary Lagrangian-Eulerian (ALE) methods
  • Résolution of advection diffusion equations (Navier-Stokes equations, transport of chemical species)
  • Mechanics of contact between deformable bodies, contact algorithms
  • Non-linear heat transfer with phase change
  • Coupling between thermomechanics and phase changes (liquid/solid, in the solid state)
  • Thermo-mechanical analysis of two-phase flows (mushy zone, semi-solid flow)
  • Identification of constitutive models for metals at high temperature, in the solid state and in the mushy state, by inverse finite element techniques applied to instrumented tests
  • Modeling of solidification processes: shape casting, ingot casting, continuous casting
  • Modeling of welding processes: arc, hybrid laser-arc
  • Modeling of powder metallurgy processes: hot isostatic pressing, spark plasma sintering

Expérimental : development of tests for alloy caracterization under solidification conditions
  • Field measurements by laser speckle technique for rheological identification at high temperature
  • Instrumented tests for the study of hot tearing of steels during solidification (test "Crickacier")
  • Measurement of heat transfer coefficients
  • Instrumented welding bench for steel arc welding
  • Vacuum furnace for melting and casting of steels and superalloys
  • Compression tests for rheological characterization of aluminium alloys in the semi-solid state


Ongoing researches


  • Coupled simulation thermal-metallurgical-mechanical of steel arc welding, and validation by instrumented experiments
  • Numerical modelling of the thermomechanics of primary cooling in steel continuous casting, and interaction with fluid flow. Application to rotating continuous casting
  • Numerical study of interactions between thermo-mechanics and macrosegregation in solidification processes
  • Experimental study and numerical modelling of the behaviour of steels at high temperature and in the semi-solid state (identification of parameters by inverse analysis from tensile tests of Gleeble type )
  • Development of non-contact extensometry techniques (laser speckles) and application to the "Taboo" machine of Cemef: resistive heating tensile machine (Joule effect)
  • Experimental and numerical modelling of hot tearing (solidification cracking) in steels in solidification processes. Development of the test "Crickacier" for hot tearing in solidification conditions. Numerical modelling at the macro and the meso scales
  • Experimental and numerical study of Ni-based superalloys. Development of a furnace for vacuum melting and casting
  • Numerical modelling of the Spark Plasma Sintering Process (powder compaction)
  • Numerical modelling of hot compaction of stainless steel powder at the mesoscale
  • Development of simulation codes in collaboration with Transvalor :
    • THERCAST (solidification processes)
    • TRANSWELD (welding processes)


Teaching


At MINES ParisTech
  • Responsible of the speciality "Materials Science and Engineering" in last two years of undergraduate formation
  • "Continuum Mechanics and Heat Transfer" : MASTER M2R Physics of Materials, Mechanics and Numerical Modelling (University of Nice - Sophia Antipolis, MINES ParisTech), ADVANCED MASTER "Materials Engineering" (MINES ParisTech - CEMEF), ADVANCED MASTER "Computational Mechanics" (MINES ParisTech - CEMEF), 1st year of doctoral formation MINES ParisTech - CEMEF
  • "Introduction to plasticity and viscoplasticity" : MASTER M1 Physics of Materials, Mechanics and Numerical Modelling (University of Nice – Sophia Antipolis, MINES ParisTech)
  • "Numerical Modelling of Solidification Processes", ADVANCED MASTER "Materials Engineering" (MINES ParisTech - CEMEF)
  • "Elastic-Viscoplastic Constitutive Equations", ADVANCED MASTER "Materials Engineering" (MINES ParisTech - CEMEF)
  • "Modelling of Thermal-Metallurgical-Mechanical Interactions", Doctoral Lecture MINES ParisTech, open to students of last two years of undergraduate formation (European Network ATHENS) "Non-Linear Computational Mechanics"
  • "Numerical Modelling of Solidification Processes", Specialty "Materials Science and Engineering" MINES ParisTech, 3rd year of undergraduate formation

In the framework of the MASTER M2R MAGIS (MINES ParisTech, Arts-et-Métiers ParisTech, ENS Cachan, Ecole Centrale de Paris, Université Pierre et Marie Curie, Ecole Polytechnique) :
  • "Modelling of Thermal Phenomena", Teaching Unit "Processing in the Fluid State"
  • "Numerical Modelling in Solidification", Teaching Unit "Multiphysics Modelling"


B.P. 207 - 06904 Sophia Antipolis Cedex
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