Emmanuelle ROUHAUD

Experience

 

• Since 2017-09 : Professor, University of Technology of Troyes - France.
• Since 1994-09 : Associate professor, University of Technology of Troyes - France.
• 2016-09 to 2017-02 and 2014-09 to 2015-02 : Six months sabatical at CNRS Laboratoire de Physique Théorique de la Matière Condensée at the Université Pierre et Marie Curie

 

Education

 

• 1993 : PhD from Washington University in Saint-Louis, graduate Research Assistantship, from the National Science Foundation.
• Master from Washington University in Saint-Louis et PhD Mechanical engineering department.
• 1990 : Engineering Degree, Université de technologie de Compiègne in biological engineering.

Keywords 

 

Modelisation and simulation      Manufacturing processes
Finite deformations                      Residual stress
Constitutive models                     Covariance and objectivity
Material fatigue

 

Research projects 

 

• Space-time formalism for finite transformations

We wish to describe the finite transformations of matter, in particular for application to fluids and manufacturing process modeling, using four dimensions (space and time) to take advantage of the covariance principle of the Theory of Relativity. In this framework, physical entities and equations become independent of the observer. Derivatives, equivalent to derivatives with respect to time (rates) may be proposed being independent of change of observers; It can be proven that among these derivatives the Lie derivative in the velocity field, is indifferent to the superposition of rigid body motions. Also, in this context, the Lagrangian description becomes a choice of coordinates. We have further proposed a formulation for thermodynamics in a covariant form. Constitutive models with application to hyperelasticity, viscoelasticity and elastoplasticity have been also constructed. We have proposed a 4D weak formulation of the problem and are developing a 4D finite element for a numerical space-time resolution.

• Residual stresses and prestressing manufacturing processes

The current environmental and energy crisis is pushing the industries to design increasingly efficient equipment. At the same time, the structures are submitted to higher loadings. If the link between stress and service life has been relatively well explored, this is not the case for the link between manufacturing conditions and service life. The main objective of the so-called pre-stressing processes is to introduce residual stresses to increasing the service life. These processes are often used in an empirical way to offer additional guarantees without being taken into account in design. The design margins could thus be significantly reduced without compromising the integrity of the structures.
The objective of the project is to combine skills in the fields of material characterization, stress evaluation, modeling and CAD. It is a partnership between academic research and industry. We have studied the effect of surface treatment parameters such as shot peening on the residual stress state. We proposed models whose interest is to allow a rapid use in CAD. We have set up a method to introduce the mechanical fields associated with residual stresses in a part with a complex geometry. We study the dynamics of the shot to optimize the shot peening process in the case of parts with complex geometry. We are now working to establish the link between residual stresses and the lifetime of complex geometry parts for the automotive and aerospace industries.
 

Teaching activities

Continuum mechanics   Strength of materials   Mathematics
Fluid mechanics              Elasticity                         Dynamics
Solid mechanics              Biomechanics
 

Choice of publications 

Al Nahas R., A. Charles, B. Panicaud, E . Rouhaud, I. Choucair, K. Saliya, R. Kerner. Investigation on the use of a spacetime formalism for modeling and numerical simulations of heat conduction phenomena, Journal of Non-Equilibrium Thermodynamics, 2020.

Rida, A., M. Micoulaut, E. Rouhaud, A. Makke. Understanding the strain rate sensitivity of nanocrystalline copper using molecular dynamics simulations. Computational Materials Science, 172, 2020.

Barrallier L., P. Goudeau, P. Kanoute, D. Retraint, E. Rouhaud (Auteurs par ordre alphabétique) Recueil des articles du colloque Mécamat “Contraintes résiduelles : de nouveaux outils pour de nouveaux défis, elaboration, usage, durée de vie”. Aussois 2020.

Rida A., M. Micoulaut, E. Rouhaud, A. Makke, Crystals at High Deformation Rates Display Glassy Behavior, Physica Status Solidi B, 2019.

Rida A., E. Rouhaud, A. Makke, M. Micoulaut, B. Mantisi, Study of the effects of grain size on the mechanical properties of nanocrystalline copper using molecular dynamics simulation with initial realistic samples, Philosophical Magazine, 97, 2387-2405, 2017.

Altmeyer G., B. Panicaud, E. Rouhaud, M. Wang, A. Roos, R. Kerner, Viscoelasticity behavior for finite deformations, using a consistent hypoelatic model based on Rivlin materials, Continuum Mechanics and Thermodynamics, 28, 1741-1758, 2016.

Wang M., B. Panicaud, E. Rouhaud, R. Kerner, A. Roos, Incremental constitutive models for elastoplastic materials undergoing finite deformations by using a four-dimensional formalism, International Journal of Engineering Science, 106, 199-219, 2016.

Panicaud B., E. Rouhaud, G. Altmeyer, M. Wang, R. Kerner, A. Roos, O. Ameline, Consistent hypo-elastic behavior using the four-dimensional formalism of differential geometry, Acta Mechanica, 227, 651-675, 2016.

Panicaud B., E. Rouhaud, Derivation of Cosserat’s medium equations using different multi-dimensional frameworks, Acta Mechanica, 227, 367-385, 2016.
Gallitelli D., V. Boyer, M. Gelineau, Y. Colaitis, E. Rouhaud, D. Retraint, R. Kubler, L. Barrallier, Simulation of shot peening: from process parameters to residual stress fields in a structure, Comptes Rendus Mécanique, 344, 355-374, 2016.
Fait partie des articles les plus téléchargés du CRM sur le site de Elsevier au 13 janvier 2020.

Altmeyer G., E. Rouhaud, B. Panicaud, A. Roos, R. Kerner, M. Wang, Viscoelastic models with consistent hypoelasticity for fluids undergoing finite deformations, Mechanics of Time-Dependent Materials, 19, 375-395, 2015.

Wang M., E. Rouhaud, A. Roos, B. Panicaud, R. Kerner, O. Ameline, Anisotropic elastic behaviour using the four-dimansional formalism of differential geometry. Computational Materials Science, 94, 132-141, 2014.

Badreddine J., E. Rouhaud, M. Micoulaut, S. Remy, Simulation of shot dynamics for ultrasonic shot peening: the effects of process parameters. International Journal of Mechanical Sciences, 82, 179-190, 2014.

François M., G. Montay, B. Panicaud, D. Retraint, E. Rouhaud, Proceedings de European Conference on Residual Stresses Troyes, ECRS 2014, Advanced Materials Research, 2014.

Badreddine J., E Rouhaud, M. Micoulaut, D. Retraint, V. Desfontaine, P. Renaud, 3D model of shot dynamics for ultrasonic shot peening, Materials Science Forum vol. 768–769, pp. 503–509, 2014.