DEVELOPMENT OF PULTRUSION TECHNOLOGY FOR PRODUCTION OF THIN-WALLED TUBES

THE AIR FORCE DESIRES TO PULTRUDE VERY THIN TUBES. DURING PHASE I, ACT WILL DESIGN A PULTRUSION SYSTEM CAPABLE OF AUTOMATING THE PRODUCTION OF VERY THIN-WALLED TUBES, WITH WALL THICKNESSES RANGING FROM 1.0 TO 0.2 MM. SOME KEYS TO REDUCING MINIMUM PULTRUDABLE WALL-THICKNESS INCLUDE THE DEVELOPMENT OF TECHNIQUES FOR CONTINUOUS IN-LINE ASSEMBLY OF GEOMETRICALLY STABLE, ARBITRATILY-ORIENTED FIBER STRUCTURES, THE REDUCTION OF FRICTION AT THE TOOLING-TO-COMPOSITE INTERFACE, AND ESTABLISHMENT OF TECHNIQUES THAT PREVENT CRUSHING THIN TUBES IN THE GRIPPER/PULLER MECHANISM. THE PHASE I DESIGN STUDY WILL EVALUATE ALTERNATIVE FIBER-FORMING METHODS INCLUDING IN-LINE WINDING, BRAIDING AND PREFORM-WRAPPING. TECHNIQUES FOR REDUCING FRICTIONAL FORCE INCLUDING INNOVATIVE DIE DESIGN, MOVING DIE AND/OR MANDREL COMPONENTS AND LOW-FRICTION COATINGS FOR TOOLING WILL BE STUDIED. DEFORMABLE GRIPPING MECHANISMS DESIGNED TO CONFORM TO PRODUCTS WILL BE INVESTIGATED. IN ORDER TO ESTABLISH A BASELINE FOR CURRENT TECHNOLOGY, EXPERIMENTAL WORK WILL BE CONDUCTED TO MEASURE THE SMALLEST DIAMETER EPOXY-MATRIX TUBE THAT CAN CURRENTLY BE PRODUCED AS A FUNCTION OF WALL THICKNESS AND WIND ANGLE. DURING PHASE II, HARDWARE AND PROCESSING TECHNIQUES IDENTIFIED IN THE PHASE I STUDY AS IMPROVED METHODS FOR PRODUCING THIN TUBES WILL BE DEMONSTRATED. A FUNCTION OF WALL-THICKNESS AND WIND ANGLE. DURING PHASE II, HARDWARE AND PROCESSING TECHNIQUES IDENTIFIED IN THE PHASE I STUDY AS IMPROVED METHODS FOR PRODUCING THIN TUBES WILL BE DEMONSTRATED.