Method of producing composite members having increased strength

Abstract

This invention relates to extruded composite materials specifically focusing on the increasing load bearing capacity and the overall strength of composites. Injectable conformable structural core materials are used to replace foam cells inside extruded composite materials thereby increasing the overall load bearing stability and strength. The core materials are tailored to have a desired CTE with respect to the structural materials. The core materials may also incorporate fibers and solid structural fillers for increasing the strength of the composite member. The objective is to enable composite materials to have the highest structural load bearing capability possible so that these technologies can be used as the replacement of wood, in aerospace applications and for other purposes.

1 . A method of making an extruded composite member comprising the steps of: 
 extruding a structural material through a die to form an elongate structure that defines voids therein;    filling said voids with a core material comprising fibers and substantially incompressible filler material for strengthening said extruded composite member.    
     
     
         2 . The method according to  claim 1  further comprising the step of: 
 determining the coefficient of thermal expansion of said structural material; and    adjusting an amount of said filler material in said core material to achieve a desirable coefficient of thermal expansion of said core material with respect to said structural material.    
     
     
         3 . The method according to  claim 2  wherein said desirable coefficient of thermal expansion of said core material is a coefficient of thermal expansion that is selected to reduce shear stress between said core material and said structural material.  
     
     
         4 . The method according to  claim 1  wherein said core material is a foam.  
     
     
         5 . The method according to  claim 4  wherein said core material is a polyurethane composite foam.  
     
     
         6 . The method according to  claim 1  wherein said fibers are selected from a group consisting of synthetic, natural and mineral fibers.  
     
     
         7 . The method according to  claim 1  wherein said fibers contact and adhere to at least some of said filler material for strengthening said member.  
     
     
         8 . The method according to  claim 1  wherein said fibers comprise greater than approximately 45% of weight of the foam.  
     
     
         9 . The method according to  claim 1  wherein said fibers comprise greater than approximately 60% of weight of the foam.  
     
     
         10 . The method according to  claim 2  wherein said filler material is microspheres.  
     
     
         11 . A method of making an extruded composite member comprising the steps of: 
 determining the coefficient of thermal expansion of a structural material;    adding a selected amount of filler material to a core material to achieve a desirable coefficient of thermal expansion of said core material with respect to said structural material;    extruding said structural material through a die to form an elongate structure that defines voids therein;    filling said voids with said core material.    
     
     
         12 . The method according to  claim 11  wherein said desirable coefficient of thermal expansion of said core material is a coefficient of thermal expansion of selected to reduce shear stress between said core material and said structural material.  
     
     
         13 . The method according to  claim 11  wherein said core material is a foam.  
     
     
         14 . The method according to  claim 11  wherein said core material is a polyurethane composite foam.  
     
     
         15 . The method according to  claim 11  further comprising a step of: 
 adding fibers to said core material for strengthening said extruded composite member.    
     
     
         16 . The method according to  claim 15  wherein said fibers are selected from a group consisting of synthetic, natural and mineral fibers.  
     
     
         17 . The method according to  claim 15  wherein said fibers comprise greater than approximately 45% of weight of the foam.  
     
     
         18 . The method according to  claim 15  wherein said fibers comprise greater than approximately 60% of weight of the foam.  
     
     
         19 . A method of making an extruded member comprising the steps of: 
 incorporating fibers and substantially incompressible filler material into a foam material;    extruding said foam material through a die to form an elongated member.    
     
     
         20 . The method according to  claim 19  wherein said filler material comprises microspheres.  
     
     
         21 . The method according to  claim 19  wherein said fibers are selected from a group consisting of natural, synthetic and mineral fibers.  
     
     
         22 . A method of making an extruded composite member comprising the steps of: 
 adding a selected amount of filler material to a core material to achieve a desirable coefficient of thermal expansion of said core material with respect to said structural material;    extruding said structural material through a die to form an elongate structure that defines voids therein;    filling said voids with said core material.    
     
     
         23 . A method of making extruded members comprising the step of: 
 applying a particle coating to an extruded member;    rolling an embossing wheel over said member to embed said particles into said member to create a non-skid surface.    
     
     
         24 . The method according to  claim 23  further comprising the step of: 
 applying a spray sealant with a UV additive and abrasion resistant particles to said extruded member, wherein said abrasion resistant particles prevent subsequent wear of said UV additive off of said member.    
     
     
         25 . The method according to  claim 24  wherein said step of rolling said embossing wheel creates a simulated wood grain pattern; and 
 said applied sealant is thicker in said embossed areas to create a natural wood grain stained appearance.