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Accueil du site > Divers > equipes de recherche > Matériaux Fonctionnels et de Structure (MFS) > Activités > Microstructure et comportement des matériaux

Microstructure et comportement des matériaux

 

 

Introduction

 

Like other research areas, nowadays materials science must take environmental, economic and social sides into account when developing new materials. Among these considerations are : the production energy cost for the material, the environmental impact of its production and use, the energy saved due to the use of this material. 

 

Production energy cost

 

For clay-based domestic ceramics, the requirements for energy costs reduction call for intensive investigations on the selection of raw materials, the formulation of the pastes and the firing conditions. Joint research programs are active on these topics with the GEMH laboratory of ENSCI Limoges, the laboratory for Sustainable Thermal Energies and the one of Physico-chemistry and Technology of Materials at Ouagadougou (Burkina Faso) as well as the Department of Physico-chemistry of Materials at Casablanca (Morocco), supported by the Institut de Recherche pour le Développement (IRD) [Kam - Applied Clay Science-2009 ; Traoré - J. Eur. Ceram. Soc. - 2007 ; Traoré - C.R. Chimie-2007 ; Arib - C.R. Chimie -2007 ; Kam - J. Soc. Ouest-Afr. Chim. -2009].

 

 

Environmental impact

 

On Diesel engines the activated particulate filter (PF) is designed to reduce significantly the amount of emitted particles issued from gas combustion. The sooting of the filter is avoided by rising the inner temperature of the exhaust pipe at regular time intervals. That regeneration process may induce damages which result in a lack of filtration. The main objectives of the ANR-promoted DuraFAP project (for sustainability of particulate filter) are : (i) insights into the physical damaging mechanisms, (ii) investigation of the thermomechanical behaviour of the base material the PF is made of, (iii) development of a numerical modelling software aimed at designing PF. This join research program associates PSA PEUGEOT CITROËN, SAINT-GOBAIN, FAURECIA, ARMINES CdM and CRISMAT laboratory. In the literature little information is available on the damaging problems of porous honeycomb ceramic materials like these particule filters. Damages are not induced by cyclic loading but rather by the combination of temperature within the filter upon regeneration (maximum value of gradient) and structure of the honeycomb material. That means brittle fracture mechanism typical of bulk ceramic behaviour is likely to occur rather than fatigue-like mechanism.

 

 

Reduction of Energy consumption
 
 

Regarding materials aimed at structural applications, the enhancement of energy requires substantial lightening. Operating conditions permitting one can be obtained by mastering organic matrix composites. The Mov’eo-promoted TOUPIE project addresses this topic for aeronautic applications ; it associates a few companies (AIRCELLE - Le Havre of Safran Group, AMPA of Dedienne Plasturgie Group, AXS Ingénierie) and public research centres (LOMC, INSA Rouen, ARMINES CdM and CRISMAT). The objectives are the identification of the key parameters (optima heating cycle and pressure) and evaluation of the stamping process for producing structural parts made of high performance carbon/thermoplastic composites. The Mov’eo-promoted Structural RTM project (same partnership as above except ARMINES CdM) is aimed at demonstrating the availability of resin transfer moulding for the fabrication of complex shape aeronautic parts. For structural applications at much lower stress levels, vegetable fibres can be substituted for glass and carbon fibres. At present, reinforcement of resin polymers by flax fibres is a joint research topic for a number of public centres : LOMC of Le Havre University, IFRMP of Rouen University and L2PIC of South Britain University [Charlet - RCMA-2008 ; Charlet - Journal of Composite Materials - 2010 ; Charlet - Carbohydrate Polymers -2010].
 
 
 
 
 

 

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