The project will study the fundamentals of monitoring in-situ consolidation of thermoplastic composites in filament winding based on dynamic dielectric analysis. In spite of its demonstrated advantages in production rate, cost, and process flexibility, thermoplastic filament winding with in-situ consolidation has not been widely accepted for industrial applications because of the high void content of the wound part resulting from the variation of consolidation at the filament lay down point. The investigation aims at identifying the degree of thermoplastic resin consolidation at the lay down point through analyzing its resin rheology properties by frequency-dependent electromagnetic sensing methodology. The uniqueness of the research is the concept of imbedding dynamic dielectric measurement in the compaction process to provide a near-field, non-destructive, and non-intrusive sensing technique which enables the in-process assessment of the critical material properties that directly contribute to the part quality and productivity. The work will formulate the analytical basis of the technique, establish the fundamental understanding of the relationship between dynamic dielectric parameters (namely the permittivity, loss factor and conductivity) and the in-situ consolidation process, demonstrate the concept feasibility through simulation testings, and explore the advantages and limitations of the methodology through prototype system implementation on a filament winding station. The successful completion of this research is expected to remove a major obstacle in the advancement of filament winding technology by the establishment of a much needed in-process monitoring methodology. The investigation will also open up new opportunities for feedback control and optimization research in the critical area of intelligent processing of advanced composites.
