Forming Composite Features Using Steered Discontinuous Fiber Pre-Preg

Abstract

Interlaminar features of a composite structure are laid up by placing and steering individual chopped fiber pre-preg segments onto a substrate.

What is claimed is: 
     
         1 . A method of forming a composite feature having discontinuous reinforcement fibers, comprising:
 producing a plurality of resin infused fiber segments each having unidirectional reinforcing fibers;   placing the resin infused fiber segments on a substrate; and,   arranging the resin infused fiber segments such that the reinforcing fibers of resin infused fiber segments placed on the substrate are substantially aligned relative to a desired reference orientation.   
     
     
         2 . The method of  claim 1 , wherein producing the resin infused fiber segments includes chopping scrap fiber pre-preg into individual pieces. 
     
     
         3 . The method of  claim 1 , wherein producing the resin infused fiber segments is performed by splitting fiber pre-preg along and between the reinforcing fibers into individual pieces. 
     
     
         4 . The method of  claim 1 , wherein placing the resin infused fiber segments on the substrate includes:
 moving a applicator over the substrate, and   dispensing the resin infused fiber segments from the applicator onto the substrate as the applicator moves over the substrate.   
     
     
         5 . The method of  claim 4 , wherein arranging the resin infused fiber segments includes aligning the resin infused fiber segments as they are being dispensed from the applicator onto the substrate. 
     
     
         6 . The method of  claim 4 , wherein producing the resin infused fiber segments is performed by:
 drawing continuous fiber pre-preg tape from the applicator, and   chopping the pre-preg tape into the resin infused fiber segments as the resin infused fiber segments are being dispensed from the applicator onto the substrate.   
     
     
         7 . The method of  claim 4 , wherein dispensing the resin infused fiber segments from the applicator includes dispensing a bandwidth of the resin infused fiber segments onto the substrate. 
     
     
         8 . The method of  claim 1 , wherein placing the resin infused fiber segments on the substrate is performed by introducing the resin infused fiber segments into an airstream, and using the airstream to stream the resin infused fiber segments from an applicator head onto the substrate. 
     
     
         9 . The method of  claim 8 , wherein streaming the resin infused fiber segments is performed by:
 introducing the resin infused fiber segments into an airstream, and   using the airstream to project the resin infused fiber segments onto the substrate.   
     
     
         10 . The method of  claim 1 , wherein arranging the resin infused fiber segments is performed after the resin infused fiber segments have been placed on the substrate. 
     
     
         11 . The method of  claim 1 , further comprising:
 applying resin to the substrate before the resin infused fiber segments are placed on the substrate.   
     
     
         12 . The method of  claim 1 , further comprising applying a resin on at least one end of each of the resin infused fiber segments before they are placed on the substrate. 
     
     
         13 . A method of laying up composite material on a substrate, comprising:
 placing individual chopped fiber pre-preg segments on the substrate; and,   controlling an orientation of the pre-preg segments on the substrate.   
     
     
         14 . The method of  claim 13 , wherein placing the pre-preg segments on the substrate is performed by:
 moving an applicator head over the substrate along a desired path, and   dispensing the pre-preg segments from the applicator head onto the substrate as the applicator moves over the substrate.   
     
     
         15 . The method of  claim 14 , wherein controlling an orientation of the pre-preg segments is performed by substantially aligning the pre-preg segments being dispensed from the applicator head relative to a desired orientation. 
     
     
         16 . The method of  claim 13 , wherein controlling an orientation of the pre-preg segments includes changing the orientation of the pre-preg segments after the pre-preg segments have been placed on the substrate. 
     
     
         17 . A composite laminate structure layup, comprising:
 a plurality of layers of composite material, each of the layers including a plurality individual chopped fiber pre-preg segments having substantially aligned fiber orientations.   
     
     
         18 . The composite laminate structure layup of  claim 17 , wherein the fiber orientations of the chopped fiber pre-preg segments are substantially aligned with a non-linear load path through the composite laminate structure. 
     
     
         19 . The composite laminate structure layup of  claim 17 , wherein each of the individual chopped fiber pre-preg segments has an aspect ratio of approximately 6:1. 
     
     
         20 . The composite laminate structure layup of  claim 17 , wherein the plurality of layers of composite material have a tailored cross-sectional shape and is contoured along a length of the layup. 
     
     
         21 . Apparatus for laying up a composite structure, comprising:
 an applicator adapted to move over a substrate, and dispense at least one stream of substantially aligned chopped, resin infused fiber segments onto the substrate.   
     
     
         22 . The apparatus of  claim 21 , further comprising a computer controlled manipulator for moving the applicator along a preselected path over the substrate. 
     
     
         23 . The apparatus of  claim 21 , wherein the applicator includes:
 a supply of continuous resin infused fiber, and   a chopper for chopping the continuous resin infused fiber into individual resin infused fiber segments.   
     
     
         24 . The apparatus of  claim 23 , wherein the applicator includes an airstream generator for streaming the resin infused fiber segments from the applicator onto the substrate. 
     
     
         25 . The apparatus of  claim 21 , wherein the applicator is adapted to simultaneously dispense multiple streams of substantially aligned chopped, resin infused fiber segments onto the substrate.