Manufacturing of braided thermoplastic composites with commingled fibers.

摘要

Through this work, an investigation on thermoplastic composites manufactured with braided commingled fibers is performed. Thermoplastic composites have the potential for complex shape part manufacturing with a cost-effective perspective. However they present a manufacturing challenge because of the high melt viscosity of their matrices. Among the many solutions to this problem commingled yarns present a promising avenue. The commingled yarn studied here is a carbon/nylon yarn from Schappes Techniques France. Braiding is used to manufacture preforms from this yarn. Bi-axial braiding is described with the mathematical relations regulating the process. The machine available in the lab has been calibrated and seven fabrics have been produced with seven different braiding conditions to explore the preforming method. The fabrics have been consolidated using compression molding. A model to predict the final thickness of the consolidated braid is proposed. The evaluation of the quality of the consolidation was performed using a constituent content method and a qualitative observation by microscopy. Both methods were developed in the scope of this work. Flexural and tensile mechanical properties of the consolidated laminates are tested. The tensile modulus data are compared to a mathematical model using the classical lamination theory.