IDENTIFICATION OF GLASS-FIBER THERMOSETTI NG RESINS COMPOSITES THERMAL-PROPERTIES - APPLICATION TO THE OPTIMIZATION OF MOLDING PROCESSES

Identification of glass fiber/thermosetting resins composites thermal properties. Application to the optimization of molding processes. A pr ocedure has been developed to optimize molding processes of thermosett ing composite materials. Three stages have been distinguished. In the first one, some thermal and kinetic properties have been measured by d ifferential scanning calorimetry Thermal conductivities have been iden tified afterwards in thick instrumented pieces, placed in a thermally regulated press. High dependences of thermal conductivities on tempera ture and transformation degree have been shown. Secondly, coupled heat transfers have been numerically simulated and results have been satis factorily compared with experimental thermograms. Finally, optimizatio n technics based on effective inverse methods have been used. These po ints have been illustrated with two examples : glass fiber/epoxy resin and glass fiber/polyester. Sufficient mechanical characteristics of t he first one, which is cured in oven, and good surface aspect of the s econd, that is made by injection in heated and closed molds, had to be obtained. The results let foresee veal improvement of the correspondi ng molding processes.