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Seeking a Postdoctoral position in mechanical and material engineering

gayoub's picture

My name is Georges Ayoub; I am seekinging a postdoctoral research position in mechanical and material engineering. I defended my PHD at the beginning of this academic year (2010/2011) and the examining committee gave me the title of doctor in mechanical engineering with a very honourable mention and with the examining committee praise (they judged my work as an excellent one). I am very motivated to start a Postdoctoral position in January, in the USA.

My current researches are concentrated on two main axes:  the development of constitutive equations for polymers and the fatigue life prediction and I published my work on international journal of plasticity (IJP two articles) and Journal of the Mechanics and Physics of Solids (JMPS 2 articles) and I participated to international conferences as International Conference on Polymer Behavior (ICPB), 11th Pan-American Congress of Applied Mechanics Pacam XI and international fatigue conference and my contributions on this latest conferences are published in Procedia engineering (2articles). I am a very motivated person and able to adapt to new working conditions. I am very curious and interested in exploring another area of research than mine.  Thesis abstractTwo representative polymers are studied in this thesis: a semi-crystalline thermoplastic (polyethylene) and an elastomer (styrene-butadiene rubber SBR).A physically-based hyperelastic-viscoplastic model integrating the crystallinity effects is proposed to describe the mechanical behavior under large deformation of polyethylene. The capabilities of the proposed model to reproduce the mechanical behavior of typical thermoplastic (viscoplastic-hyperelastic) to the mechanical behavior more typical of elastomers (visco-hyperelastic) are demonstrated. The proposed model is modified by incorporating a non-linear viscous component to capture the mechanical behavior of polyethylene under cyclic loading. To describe the damage process under multiaxial cyclic loading of SBR, two complementary approaches have been used. The first one, based on the network alteration theory, allows describing the stress-softening until failure. The comparison between the proposed model and experimental results obtained under uniaxial cyclic loading highlighted the relevance of such approach. The second one, based on the continuum damage mechanics theory, aims to predict the multiaxial fatigue life under complex loadings of rubber-like materials. In this approach, the damage variable is derived from the cracking energy density. After identifying the damage parameters using uniaxial fatigue data, the predictive capabilities of the proposed model are highlighted under multiaxial loadings, combining tension and torsion tests. Dr. Georges Ayoub École polytechnique universitaire de lille Avenue Paul Langevin Bureau D232Office : +33 3 20434614Cel. : +33 6 17088467georges.ayoub@polytech-lille.frlab website: http://lml.univ-lille1.fr/lml/?page=15&manID=1217

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Hayder EL AMARI's picture

I have started a PhD sbject concentrated on : "plastic viscoelastic damage behavior of an energetic material".

I would like to ask you if you have an idea about  Schapery's Model?

gayoub's picture

Sorry but the model i used in my publications to model the viscoplastic-viscoelastic behavior are the VBO and the arrhenius models.

you can find details by reading these papers:

Modeling the low-cycle fatigue behavior of visco-hyperelastic elastomeric materials using a new network alteration theory: Application to styrene-butadiene rubber  Original Research Article
Journal of the Mechanics and Physics of Solids, In Press, Corrected Proof, Available online 15 October 2010
G. Ayoub, F. Zaïri, M. Naït-Abdelaziz, J.M. Gloaguen

Effects of crystal content on the mechanical behaviour of polyethylene under finite strains: Experiments and constitutive modelling  Original Research Article
International Journal of Plasticity, In Press, Corrected Proof, Available online 23 July 2010
G. Ayoub, F. Zaïri, C. Fréderix, J.M. Gloaguen, M. Naït-Abdelaziz, R. Seguela, J.M. Lefebvre


Modelling large deformation behaviour under loading–unloading of semicrystalline polymers: Application to a high density polyethylene  Original Research Article
International Journal of Plasticity, Volume 26, Issue 3, March 2010, Pages 329-347
G. Ayoub, F. Zaïri, M. Naït-Abdelaziz, J.M. Gloaguen


Modelling of photodegradation effect on elastic–viscoplastic behaviour of amorphous polylactic acid films  Original Research Article
Journal of the Mechanics and Physics of Solids, Volume 58, Issue 2, February 2010, Pages 241-255
S. Belbachir, F. Zaïri, G. Ayoub, U. Maschke, M. Naït-Abdelaziz, J.M. Gloaguen, M. Benguediab, J.M. Lefebvre

 And for more details and to discuss these models you can send me email on georges.ayoub@polytec-lille.fr

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