Optimization Of Impregnation Process Of Continuous Fiber Reinforced Thermoplastic Composites

Continuous fiber reinforced thermoplastic composites have broad development prospects in many fields represented by aerospace due to their excellent performance.Melt impregnation is the most suitable composite pre-impregnation technology for a wide range of industrial applications.The impregnation degree and fiber fracture rate during the impregnation process affect the final properties of the composite.The research on the melt impregnation process of the curved channel impregnation mold shows that the effect factors of the melt impregnation are very complicated,and it is necessary to systematically analyze according to impregnation mechanism of melt impregnation.In this paper,the pressure distribution and melt flow process in the impregnation mold are systematically studied.The process of establishing the melt pressure in the melt impregnation process is described by the Reynolds equation.The process that fiber bundle is impregnated under the pressure of the resin melt is described by Darcy’s law.In order to overcome the disadvantage that the numerical method of the Reynolds equation is complex,the Reynolds equation is simplified and combined with Darcy’s law to obtain an impregnation model in analytical solution that is convenient to use.The fiber fracture process is described by the Weibull distribution function.The force condition of the fiber in the impregnation mold is analyzed,and reasonable assumptions are made.The force condition of the fiber is combined with the Weibull distribution function to establish the fiber fracture model during the impregnation process.The analysis results of the impregnation model and the fiber fracture model show that the increase of the number of wedge zones,the length of wedge zone,the width of fiber bundle,the fiber bundle tension,and the decrease of the pulling speed,the resin melt viscosity,the channel fillet radius,the mold gap will increase the impregnation degree.The decrease of the number of wedge zones,the length of wedge zone,the width of fiber bundle,the fiber bundle tension,the pulling speed,the resin melt viscosity,and the increase of the channel fillet radius,the mold gap will reduce the fiber fracture rate.According to the established impregnation model and fiber fracture model,the Design Expert software is used to comprehensively analyze the significance and influence degree of the effect factors on impregnation degree and fiber fracture rate,then the mold structure parameters and process parameters in the impregnation process are optimized.It can be realized that the impregnation process can achieve a higher impregnation degree at the lowest possible fiber fracture rate.