FILAMENT WINDING PROCESS FOR THERMOPLASTIC MATRIX COMPOSITES

A METHOD FOR FUSION AND COMPACTION IN-SITU FILAMENT WINDING WITH ADVANCED THERMOPLASTIC/GRAPHITE FIBER CO-MINGLED STRANDS IS PROPOSED. HEAT FOR FUSION WILL BE SUPPLIED THROUGH ELECTROMAGNETIC INDUCTION CURRENTS. EXPLORATORY EXPERIMENTS HAVE SHOWN THAT EDDY CURRENT HEATINGOF GRAPHITE FIBERS CAN BE DIRECTED AND CONFINED TO THE INTERFACE BOND LINE TO ACHIEVE MELT TEMPERATURE (700 DEGREE(F) TO 800 DEGREE(F)) IN THE THERMOPLASTIC MATRIXTO FORM A SOLID STRUCTURAL COMPOSITE. COMPACTION OF THE FIBER STRANDS WHILE THE RESIN IS MOLTEN CAN BE ACCOMPLISHED THROUGH PROPER DESIGN OF A PRESSURE APPLICATION DEVICE THAT WILL CONFORM TO CROSS-OVERS AND OTHER SURFACE IRREGULARITIESENCOUNTERED IN THE FILAMENT WINDING PROCESS. THE SPECIFIC AREAS OF STUDY INCLUDE FERRITE MAGNET DESIGNS, COIL WINDINGS, EDDY CURRENT BRAKES, STRAY FIELD SHIELDING, AND FLUX DENSITY CONTROL RELATIVE TO THE CREATION OF SECONDARY CURRENTS WITHIN THE GRAPHITE FIBER ARRAY OF THE COMPOSITE. IN ADDITION, THE MECHANICS REQUIRED OF THE COMPACTING DEVICE AND THE SELECTION OF PRESSURE APPLICATORS THAT ARE COMPATIBLE WITH INDUCTION HEATING WILL BE DEVELOPED.