Noodle Comprised of a Matrix of Discontinuous Filaments

Abstract

A method and apparatus for manufacturing a filler for a composite structure. The apparatus may comprise a filler. The filler may comprise a fiber matrix that is uniform in all directions. The fiber matrix may comprise a first plurality of discontinuous filaments and a second plurality of discontinuous filaments. Each filament of the first plurality of discontinuous filaments may be comprised of a stiffening material. Each filament of the second plurality of discontinuous filaments may be comprised of a binding material. Discontinuous filaments of both the first plurality of discontinuous filaments and the second plurality of discontinuous filaments may be randomly oriented and entangled with each other.

What is claimed is: 
     
         1 . An apparatus comprising:
 a filler comprising a fiber matrix that is uniform in all directions, wherein the fiber matrix comprises:
 a first plurality of discontinuous filaments in which each filament of the first plurality of discontinuous filaments is comprised of a stiffening material; and 
 a second plurality of discontinuous filaments in which each filament of the second plurality of discontinuous filaments is comprised of a binding material,
 wherein discontinuous filaments of both the first plurality of discontinuous filaments and the second plurality of discontinuous filaments are randomly oriented and entangled with each other. 
 
   
     
     
         2 . The apparatus of  claim 1 , wherein the stiffening material comprises at least one of carbon, silica, glass, boron, a para-aramid synthetic fiber, a polyimide, a ceramic material, or a metallic material. 
     
     
         3 . The apparatus of  claim 1 , wherein the binding material comprises at least one of a thermoplastic material or a thermoset material. 
     
     
         4 . The apparatus of  claim 1 , wherein the filler is used for substantially filling a void of a composite structure and wherein the filler has a set of filler properties that substantially match a set of properties of the composite structure. 
     
     
         5 . The apparatus of  claim 1 , wherein the filler further comprises:
 a resin infused within the fiber matrix.   
     
     
         6 . The apparatus of  claim 1 , wherein the filler further comprises:
 an additional binder within the fiber matrix to toughen the filler.   
     
     
         7 . The apparatus of  claim 1 , wherein each of the discontinuous filaments has a length of at least about one millimeter. 
     
     
         8 . A method for manufacturing a filler for a composite structure, the method comprising:
 mixing a first plurality of discontinuous filaments with a second plurality of discontinuous filaments to form a mixture;   forming feedstock material using the mixture;   compressing the feedstock material to form a feedstock in which discontinuous filaments of the first plurality of discontinuous filaments and the second plurality of discontinuous filaments within the feedstock are randomly oriented and entangled with each other to form a fiber matrix that is uniform in all directions; and   shaping the feedstock to form a filler structure for use in forming the filler.   
     
     
         9 . The method of  claim 8 , wherein mixing the first plurality of discontinuous filaments with the second plurality of discontinuous filaments comprises:
 mixing the first plurality of discontinuous filaments comprised of a stiffening material with the second plurality of discontinuous filaments comprised of a binding material.   
     
     
         10 . The method of  claim 9 , wherein mixing the first plurality of discontinuous filaments comprised of the stiffening material with the second plurality of discontinuous filaments comprised of the binding material comprises:
 mixing the first plurality of discontinuous filaments with the second plurality of discontinuous filaments to form a substantially homogenous mixture.   
     
     
         11 . The method of  claim 10 , wherein forming the feedstock comprises:
 applying at least one of force or pressure to the mixture to form a sheet of randomly oriented discontinuous filaments.   
     
     
         12 . The method of  claim 11 , wherein forming the feedstock material further comprises:
 cutting the sheet into a plurality of strips; and   recombining the plurality of strips to form the feedstock material.   
     
     
         13 . The method of  claim 8 , wherein compressing the feedstock material comprises:
 compressing the feedstock material with respect to three dimensions at a substantially constant rate to form the feedstock.   
     
     
         14 . The method of  claim 8 , wherein compressing the feedstock material comprises:
 compressing the feedstock material with respect to three dimensions to form the feedstock having a selected fiber volume fraction between about 5 percent and about 80 percent, wherein the feedstock is uniform in all directions.   
     
     
         15 . The method of  claim 8 , wherein shaping the feedstock comprises:
 cutting out a selected portion of the feedstock having a selected shape.   
     
     
         16 . The method of  claim 15 , wherein shaping the feedstock further comprises:
 shaping a number of edges of the selected portion of the feedstock to form the filler structure.   
     
     
         17 . The method of  claim 16 , wherein shaping the number of edges of the selected portion of the feedstock comprises:
 shaping the number of edges using at least one of a number of rollers, a mold, or a heating device.   
     
     
         18 . The method of  claim 16 , wherein shaping the number of edges of the selected portion of the feedstock comprises:
 placing the selected portion of the feedstock into a mold to shape the number of edges of the selected portion of the feedstock; and   applying heat to set the selected portion of the feedstock.   
     
     
         19 . The method of  claim 8  further comprising:
 adding an additional binder into the filler structure to form the filler. 
 
     
     
         20 . The method of  claim 19  further comprising:
 impregnating the filler structure with a resin to form the filler. 
 
     
     
         21 . A fiber matrix comprising:
 a first plurality of discontinuous filaments in which each filament of the first plurality of discontinuous filaments is comprised of a stiffening material; and   a second plurality of discontinuous filaments in which each filament of the second plurality of discontinuous filaments is comprised of a binding material in which discontinuous filaments of both the first plurality of discontinuous filaments and the second plurality of discontinuous filaments are randomly oriented and entangled with each other such that the fiber matrix is uniform in all directions.