An experimental device and an inverse method to determine the thermal conductivity of a fiber reinforced composite as a function of temperature and state of cure

摘要

The thermal conductivity of a thermosetting composite varies significantly during the injection and curing. These variations play an important role on the heat transfer within a thick part and thus on resin kinetics. In fact, it was observed experimentally that the temperature gradient through the thickness of a composite has a strong influence on the quality of surface finish. In order to perform precise non isothermal mould filling and curing simulations, a good knowledge of thermal conductivity is needed in function of temperature and state of cure. This work is concerned with the measurement of heat conductivity through the thickness of a composite part. For this purpose, an inverse method is developed together with an experimental device designed to measure the transverse thermal conductivity. The heat capacity of the material, which is needed to derive by inverse analysis the thermal conductivity, is obtained following a classical method based on DSC measurements. The data processing procedure based on inverse analysis will first be described. Then the approach will be validated for a set of experimental results obtained for a polyester resin formulation.