Research Initiation: Dynamic Dielectric Monitoring of In-situ Consolidation of Thermoplastic Filament Winding

该项目将研究基于动态介电分析的热塑性复合材料在纤维缠绕中原位固结监测的基本原理。尽管原位固结热塑性纤维缠绕具有生产效率、成本和工艺灵活性等方面的优势，但由于纤维铺设处固结的变化导致缠绕部分的空隙含量较高，因此在工业应用中尚未被广泛接受。本研究旨在通过频率相关电磁传感方法对热塑性树脂的流变特性进行分析，以确定铺设点热塑性树脂的固结程度。该研究的独特之处在于在压制过程中嵌入动态介电测量的概念，以提供近场、非破坏性和非侵入性的传感技术，从而实现对直接影响零件质量和生产率的关键材料性能的过程中评估。这项工作将阐述该技术的分析基础，建立动态介电参数(即介电常数、损耗因子和电导率)与原位固结过程之间关系的基本认识，通过模拟试验论证该概念的可行性，并通过在纤维缠绕站上的原型系统实施来探索该方法的优点和局限性。这项研究的成功完成有望通过建立亟需的在线监测方法，消除纤维缠绕技术进步的一个主要障碍。这项研究还将为先进复合材料智能加工关键领域的反馈控制和优化研究开辟新的机遇。

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.