IN-SITU SENSOR MONITORING AND INTELLIGENT CONTROL OF THE RESIN TRANSFER MOLDING PROCESS

An intelligent closed-loop expert control system has been developed fo r automated control of the resin transfer molding process of a graphit e fiber preform using an epoxy resin, E905L. The sensor model system h as been developed to make intelligent decisions based on the achieveme nt of landmarks in the cure process, such as full preform impregnation , the viscosity. and the degree of cure of the resin rather than time or temperature. In-situ frequency dependent electromagnetic sensor (FD EMS) and the Loos resin transfer model are used to monitor and control the processing properties of the epoxy resin during RTM impregnation and cure of an advanced fiber architecture stitched preform. Once corr elated with viscosity (eta) and degree of cure (alpha), the FDEMS sens or monitors and the RTM processing model predicts the reaction advance ment of the resin, viscosity and the impregnation of the fabric. This provides a direct means for monitoring. evaluating, and controlling in telligently the progress of the RTM process in situ in the mold throug hout the fabrication process and for verification of the quality of th e composites.