Study On The Process Of PEEK Thermoplastic Composites Automated Fiber Placement

The application of composites has spread from aerospace to many other fields in recent years.Automated Fiber Placement(AFP)has become one of focuses of attention in the study field of composites,to manufacture composites products of better performance more efficiently.But the study of thermoplastic composites is still not advanced enough.The study of thermoplastic composites Automated Fiber Placement in the respects of manufacturing technology and processing method will contribute to improving performance of thermoplastic composites AFP products and accelerate thermoplastic composites AFP development.This thesis studies on the main process parameters of APC-2(AS4/PEEK)thermoplastic composites AFP with once compact and twice compact and compares the two methods of thermoplastic composites AFP.This thesis firstly designs a kind of thermoplastic composites AFP head.This thermoplastic composites AFP head has functions of compacting,Clamping,re-feeding and tailoring tows.It has partial cooling function,which adapts to the high temperature occurs on the thermoplastic composites AFP head during AFP.The head can compact layups once or twice and cool or reheat layups by cool or heat compressed air.It has light weight and small volume.At last this thesis checked force applied on the head and optimized the structure by finite element software.The methods of heat transfer occurs during AFP is analyzed in this thesis,and its parameters are determined by knowledge of heat transfer and its conditions are determined by establishing theoretical models.To make sure the parameters and conditions are correct,an experiment was conducted comparing simulation results and experimental results about temperature process of APC-2(AS4/PEEK)during AFP.Finite element models are established to find out the combination of heating temperature and layup speed,which match the limits of material temperature.Within the combination of process parameters,several thermoplastic composites AFP specimen is made with different process parameters and tested by inter-laminar shear strength and porosity to study the laws between process parameters and performance of specimen.Equations show the law between main process parameters of thermoplastic composites AFP with once compact and twice compact and specimen performance of inter-laminar shear strength and porosity is established according to test results.Specimen made by optimized process parameters combination of thermoplastic composites AFP with once compact and twice compact are tested and compared.As a result,the conclusion that thermoplastic composites specimen made by AFP with twice compact has higher inter-laminar shear strength and lower porosity.