Une procedure est developpee dans le but d'optimiser deux procedes de moulage de materiaux composites a matrice thermodurcissable.Trois etapes sont distinguees. Dans la premiere, certaines proprietes thermiques et cinetiques sont mesurees par calorimetrie differentielle. Les conductivites thermiques sont quant a elles identifiees en piece epaisse instrumentee, que l'on place dans une presse regulee en temperature. De fortes variations des conductivites selon la temperature et le taux de transformation sont ainsi mises en evidence. Dans un second temps, les transferts couples sont simules et les resultats numeriques sont confrontes de maniere tres satisfaisante aux thermogrammes experimentaux. Enfin, des techniques d'optimisation sont mises en oeuvre a partir de methodes inverses performantes.Ces differents points sont illustres par deux exemples : un composite fibres de verre / resine epoxy et un composite fibres de verre / resine polyester. Il s'agit d'assurer les proprietes mecaniques du premier, qui est cuit en etuve, et l'etat de surface du second, qui est fabrique par injection dans des moules chauffes. Les premiers resultats laissent entrevoir de reelles perspectives d'amelioration de ces procedes.
Identification of glass fiber/thermosetting resins composites thermal properties. Application to the optimization of molding processes. A procedure has been developed to optimize molding processes of thermosetting composite materials. Three stages have been distinguished. In the first one, some thermal and kinetic properties have been measured by differential scanning calorimetry. Thermal conductivities have been identified afterwards in thick instrumented pieces, placed in a thermally regulated press. High dependences of thermal conductivities on temperature and transformation degree have been shown. Secondly, coupled heat transfers have been numerically simulated and results have been satisfactorily compared with experimental thermograms. Finally, optimization technics based on effective inverse methods have been used.These points have been illustrated with two examples : glass fiber/epoxy resin and glass fiber/polyester. Sufficient mechanical characteristics of the first one, which is cured in oven, and good surface aspect of the second, that is made by injection in heated and closed molds, had to be obtained. The results let foresee real improvement of the corresponding molding processes.