Load bearing structure and method of manufacture thereof

Abstract

A load bearing structure configured to bear a load, the structure comprising a multiple cells. The load bearing structure has a length, a center, and a cell density, which varies at least along the length of the load bearing structure, which weighs at least 6 kg.

1 . A load bearing structure configured to bear a load, said load bearing structure comprising a plurality of cells, said load bearing structure having a length, a center, and a cell density, wherein said cell density varies at least along said length, and said load bearing structure having a mass of at least 6 kg.  
   
   
       2 . The load bearing structure of  claim 1 , wherein said plurality of cells comprises open cells.  
   
   
       3 . The load bearing structure of  claim 1 , wherein said cell density varies symmetrically from the center of said load bearing structure.  
   
   
       4 . The load bearing structure of  claim 3 , wherein said cell density is concentrated in a region bearing a substantial component of said load.  
   
   
       5 . The load bearing structure of  claim 1 , wherein said cell density varies unsymmetrically from the center of said load bearing structure.  
   
   
       6 . The load bearing structure of  claim 1 , wherein said plurality of cells comprises at least one closed cell.  
   
   
       7 . The load bearing structure of  claim 14 , wherein said load is greater than about 10 kN.  
   
   
       8 . The load bearing structure of  claim 1 , which is a support beam.  
   
   
       9 . The load bearing structure of  claim 1 , which is a railway sleeper.  
   
   
       10 . The load bearing structure of  claim 9 , further comprising a consolidated part.  
   
   
       11 . The load bearing structure of  claim 9 , wherein the consolidated part is a rail support mechanism.  
   
   
       12 . The load bearing structure of  claim 11 , wherein said rail support mechanism is a support structure attachment mechanism.  
   
   
       13 . The load bearing structure of  claim 1  comprising at least one polymeric material  
   
   
       14 . The load bearing structure of  claim 13 , wherein said polymeric material is selected from the group consisting of themoplastics, thermosets and combinations thereof.  
   
   
       15 . The load bearing structure of  claim 14 , wherein said polymeric material is selected from the group consisting of polycarbonates, polyamides, olefin polymers, polyesters, polyestercarbonates, epoxides, polysulfones, polyethers, polyetherimides, polyimides, silicone polymers, mixtures of the foregoing polymers, copolymers of the foregoing polymers, and mixtures thereof.  
   
   
       16 . The load bearing structure of  claim 1  comprising at least one composite material.  
   
   
       17 . The load bearing structure of  claim 16 , wherein said composite material comprises an organic polymeric matrix and a filler material dispersed therein.  
   
   
       18 . The load bearing structure of  claim 17 , wherein the filler material is a glass fiber.  
   
   
       19 . The load bearing structure of  claim 17 , wherein the filler material is a carbon fiber.  
   
   
       20 . The load bearing structure of  claim 17 , wherein the filler material is a polymeric fiber.  
   
   
       21 . The load bearing structure of  claim 17 , wherein the filler material is a natural fiber.  
   
   
       22 . The load bearing structure of  claim 17 , wherein the organic polymeric matrix is selected form the group consisting of thermoplastics, thermosets and combinations thereof.  
   
   
       23 . The load bearing structure of  claim 17 , wherein the filler material is configured to decrease dimensional variation.  
   
   
       24 . The load bearing structure of  claim 23 , wherein the filler material is selected from the group consisting of carbon fibres and zeolites.  
   
   
       25 . The load bearing structure of  claim 17 , wherein the load bearing structure comprises functional surfaces.  
   
   
       26 . The load bearing structure of  claim 25 , wherein said functional surfaces comprises a coating selected from the group consisting of weatherable coating, chemical resistance coating anti algae coating, anti slip coating and combinations thereof.  
   
   
       27 . The load bearing structure of  claim 9 , wherein the railway sleeper is configured to be compatible with a girder bridge, a ballasted track or a ballast less track.  
   
   
       28 . A method of manufacturing a load bearing structure, the method comprising: 
 providing a mold having cavities complimentary to the load bearing structure;    molding a polymeric material into the mold; and    recovering the load bearing structure from the mold,    wherein the load bearing structure configured to bear a load, the load bearing structure comprising a plurality of cells, the load bearing structure having a length, a center, and a cell density, wherein said cell density varies at least along said length, and the load bearing structure having a mass of at least 6 kg.    
   
   
       29 . The method of  claim 28 , wherein said molding comprises one selected from the group consisting of high pressure plastic injection molding, high pressure structural foam molding, low pressure structural foam molding, gas assist injection molding, extrusion, thermoset molding, injection-compression molding, water assist molding and combinations thereof.  
   
   
       30 . The method of  claim 28 , wherein the mold has cavities complimentary to a rib cell structure.  
   
   
       31 . The method of  claim 28 , further comprising co-molding a functional part into the load bearing structure.  
   
   
       32 . The method of  claim 28 , further comprising surface-treating the load bearing structure.  
   
   
       33 . The method of  claim 32 , wherein said surface treating is selected from the group consisting of painting, plating, electrolytic coating, spraying and combinations thereof.