Foam sheet core for composite sandwich structures and method of making the same

Abstract

A foam sheet core, including a plurality of foam sheet walls defining an array of hollow cells, wherein the plurality of foam sheet walls are bonded together to form the array of hollow cells, each of the plurality of foam sheet walls has a thickness from about 0.002 inches to about 0.08 inches, and each of the plurality of foam sheet walls has an average height from about 0.05 inches to about 5 inches.

What is claimed, is: 
     
         1 . A foam sheet core, comprising:
 a plurality of foam sheet walls defining an array of hollow cells,   wherein the plurality of foam sheet walls are bonded together to form the array of hollow cells,   wherein each of the plurality of foam sheet walls has a thickness from about 0.002 inches to about 0.08 inches, and   wherein each of the plurality of foam sheet walls has an average height from about 0.05 inches to about 5 inches.   
     
     
         2 . The foam sheet core of  claim 1 , wherein the plurality of foam sheet walls are fusion bonded together to form the array of hollow cells,
 wherein the foam sheet core consists essentially of the plurality of foam sheet walls defining the array of hollow cells, and   wherein the foam sheet core does not include an adhesive.   
     
     
         3 . The foam sheet core of  claim 1 , wherein each of the array of hollow cells has an average diameter from about 0.1 inches to about 1.0 inches. 
     
     
         4 . The foam sheet core of  claim 1 , wherein the plurality of foam sheet walls comprise a foamed polymer, and wherein the foamed polymer comprises at least one of phenolic, epoxy, polystyrene (PS), polyethylene (PE), polypropylene (PP), polyamide (PA), polyethylene terephthalate (PET), polyether ether ketone (PEEK), polyetherketoneketone (PEKK), polycarbonate (PC), polyetherimide (PEI), polyphenylsulfone (PPSU), thermoplastic polyurethane (TPU), acrylonitrile butadiene styrene (ABS), polyvinyl Chloride (PVC), polyurethane (PU), or combinations thereof. 
     
     
         5 . The foam sheet core of  claim 4 , wherein at least one of the plurality of foam sheet walls comprises a different foamed polymer than the rest of the plurality of foam sheet walls. 
     
     
         6 . The foam sheet core of  claim 4 , wherein the foamed polymer has a relative density to solid from about 2.5% to about 100% and a melting temperature from about 270° F. to about 800° F. 
     
     
         7 . The foam sheet core of  claim 4 , wherein the plurality of foam sheet walls further comprise reinforcing fibers, and wherein the reinforcing fibers comprise one or more of carbon fibers, fiberglass fibers, aramid fibers, ultra-high molecular weight polyethylene (UHMWPE) fibers, polyester fibers, polypropylene (PP) fibers, polyethylene (PE) fibers, polyamide fibers, or combinations thereof. 
     
     
         8 . The foam sheet core of  claim 4 , wherein at least one of the hollow cells in the array of hollow cells comprises a filling material, and wherein the filling material comprises at least one of rubber foam, epoxy, phenolic, polystyrene (PS) foam, polyurethane (PU) foam, polyester foam, melamine foam, or combinations thereof. 
     
     
         9 . The foam sheet core of  claim 8 , wherein the filling material is different from the foamed polymer forming the foam sheet walls, and wherein the filling material enhances at least one of a fire-retardance of the foam sheet core, a rigidity or stiffness of the foam sheet core, an acoustic insulation of the foam sheet core, an impact resistance of the foam sheet core, or combinations thereof. 
     
     
         10 . A composite sandwich structure comprising:
 a foam sheet core; and   one or more skin panels,   wherein the foam sheet core is fusion bonded to the one or more skin panels, and   wherein the foam sheet core comprises a plurality of foam sheet walls defining an array of hollow cells,   wherein the plurality of foam sheet walls are bonded together to form the array of hollow cells,   wherein each of the plurality of foam sheet walls has a thickness from about 0.002 inches to about 0.08 inches, and   wherein each of the plurality of foam sheet walls has an average height from about 0.05 inches to about 5 inches.   
     
     
         11 . The composite sandwich structure of  claim 10 , wherein the composite sandwich structure is substantially-free of adhesives. 
     
     
         12 . The composite sandwich structure of  claim 10 , wherein the one or more skin panels comprises one or more of phenolic, epoxy, polypropylene (PP), polyamide (PA), polyethylene terephthalate (PET), polyether ether ketone (PEEK), polyetherketoneketone (PEKK), polycarbonate (PC), polyetherimide (PEI), polyphenylsulfone (PPSU), thermoplastic polyurethane (TPU), acrylonitrile butadiene styrene (ABS), polyvinyl Chloride (PVC), polyurethane (PU), or combinations thereof. 
     
     
         13 . A multi-core composite sandwich structure, comprising:
 two or more foam sheet cores;   one or more skin panels; and   one or more septum,   wherein the two or more foam sheet cores are fusion bonded to the one or more skin panels and the one or more septum; and   wherein each foam sheet core comprises:   a plurality of foam sheet walls defining an array of hollow cells,   wherein the plurality of foam sheet walls are bonded together to form the array of hollow cells,   wherein each of the plurality of foam sheet walls has a thickness from about 0.002 inches to about 0.08 inches, and   wherein each of the plurality of foam sheet walls has an average height from about 0.05 inches to about 5 inches.   
     
     
         14 . The multi-core composite sandwich structure of  claim 13 , wherein the multi-core composite sandwich structure is substantially-free of adhesives. 
     
     
         15 . The multi-core composite sandwich structure of  claim 13 , wherein at least one of the two or more foam sheet cores has a different functional characteristic than the rest of the two or more foam sheet cores. 
     
     
         16 . A method of making a foam sheet core for a composite sandwich structure, comprising:
 stacking two or more foam sheets into a foam sheet block;   bonding the stacked foam sheet block; and   slicing the bonded foam sheet block into one or more strips of foam sheet,   wherein the foam sheet core comprises a plurality of foam sheet walls defining an array of hollow cells, and wherein the plurality of foam sheet walls are fusion bonded together to form the array of hollow cells.   
     
     
         17 . The method of  claim 16 , further comprising:
 expanding the one or more strips of foam sheet into a foam sheet core, and   coating the foam sheet core with a resin coat.   
     
     
         18 . The method of  claim 16 , further comprising:
 filling one or more hollow cells of the array of hollow cells.   
     
     
         19 . A method of making a composite sandwich structure comprising:
 providing one or more foam sheet cores; and   bonding the one or more foam sheet cores to one or more skin panels,   wherein each of the one or more foam sheet cores comprises a plurality of foam sheet walls defining an array of hollow cells.   
     
     
         20 . The method of  claim 19 , further comprising:
 curing the one or more skin panels.