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Research Themes

Relationships between microstructures and physical properties of materials

 

  • An understanding of the macroscopic mechanical properties of materials, from the evolution of micro-mechanisms of elementary strain, thanks to: mechanical trials at the real, constant speed of strain that allows the true local behaviour of the material to be obtained (VideoTraction™)

  • Design of experiments and, or, conceptual tools that are pertinent, innovative and original. These will allow the determination of the laws of real, intrinsic mechanical behaviour starting from: in situ coupling of synchrotron radiation-Raman spectroscopy-X-Ray tomography-traction trials, of differential scanning calorimetric analysis-Raman spectroscopy, or of dielectric spectroscopy-traction trials (traction Mini-machine under MEB/AFM/SAXS/WAXS)

From left to right :
- Set up of a mini tensile test machine used in situ with MEB/AFM/SAXS/WAXS
- Striction of an isotactic polypropylene strained in uniaxial tensile mode and anayzed by X-Ray tomography
- Raman spectrum of PP/EPR using polarizors parallel and perpendicular to the machine direction axis. Evaluation of the chain orientation at the molecular scale during a tensile test

  • Analysis of the evolution of micro-mechanisms in the case of mechanical trials at real and constant speeds of strain, which allows the real, local behaviour of the material to be determined (VideoTraction™)


  • Coupling at high temperature of mechanical trials- in situ Synchrotron radiation and post-mortem characterization, to understand and quantify the mechanisms of deformation (Superalloys, TWIP steel, etc.). Project Hermes.

    

From left to right :
- Silicon samples, clamps and high temperature oven used
- Fe-Mn-C, observation of slip dislocations and strong twinning

 

  •  Modelling of the mechanical behaviour obtained

Examples of simulation and modelling of the diffraction peaks obtained

Damage to composites

 

  • Evaluation of the effects of composite damage (fibre and matrix rupture, delamination) on the global elastic properties of composite structures used in the aeronautical industry.


From left to right :
- Damage mechanisms observed in a composite with a polymer matrix reinforced by fibers
-
Structure of NCF (Non crimp fabric), arrangement of fiber bundles in the composite

  • Development of full-field methods of measurement of displacement.

Glass thermoforming

Solving the inverted problem of glass thermoforming, knowing the final form of the glass that craftsmen or industry hope to obtain

From left to right :
- Temperature and 3D displacement field Measurements at the top glass plate surface during the process in a mould used during glass thermoforming, thermo-mechanical coupling
-Taking into account precisely by modelisation surface and bulk radiative transfers taking place inside the mould: displacement fields

  • Determination of types of moulds and of the thermal history to impose on the glass

  • Development of full-field methods of displacement measurement