Thermal Modeling for the Consolidation Process of Thermoplastic Composite Filament Winding

The quality of thermoplastic composites depends on the thermal history during processing. Therefore it is important to determine the temperature distribution in the composite during the fabrication process. The objective of this investigation was to develop a comprehensive thermal model of the thermoplastic filament winding process. The model was developed in two parts to calculate the temperature profiles in the towpreg and the composite substrate. A finite element heat transfer analysis for the composite-mandrel assembly was formulated in the polar coordinate system, which facilitates the description of the geometry and the boundary conditions. A four-node ‘sector element’ is used to describe the domain of interest. Sector elements were selected to give a better representation of the curved boundary shape which should improve accuracy with fewer elements compared to a finite element solution in the Cartesian-coordinate system. The second thermal analysis was a Cartesian coordinate, finite element model of the towpreg as it enters the nippoint. The results show that the calculated temperature distribution in the composite substrate compared well with temperature data measured during winding and consolidation. The analysis also agreed with the experimental observation that the melt region is formed on the surface of the incoming towpreg in the nippoint and not on the substrate.