Fiber reinforced composite cores and panels

Abstract

A fiber reinforced core panel is formed from strips of plastics foam helically wound with layers of rovings to form webs which may extend in a wave pattern or may intersect transverse webs. Hollow tubes may replace foam strips. Axial rovings cooperate with overlying helically wound rovings to form a beam or a column. Wound roving patterns may vary along strips for structural efficiency. Wound strips may alternate with spaced strips, and spacers between the strips enhance web buckling strength. Continuously wound rovings between spaced strips permit folding to form panels with reinforced edges. Continuously wound strips are helically wrapped to form annular structures, and composite panels may combine both thermoset and thermoplastic resins. Continuously wound strips or strip sections may be continuously fed either longitudinally or laterally into molding apparatus which may receive skin materials to form reinforced composite panels.

What is claimed is: 
     
         1 . A reinforced composite panel having an upper side and a lower side comprising:
 a plurality of parallel elongated strips of low density cellular material having parallel opposite side surfaces and parallel opposite faces perpendicular to the side surfaces, wherein the elongated strips are oriented such that the side surfaces face the upper side and the lower side of the reinforced composite panel, wherein the elongated strips comprise at least one layer of helically surrounding fibrous rovings, wherein the fibrous rovings extend over the side surfaces and opposite faces of the elongated strips;   a hardened adhesive resin extending through the fibrous rovings on the opposite faces of the elongated strips forming internal reinforcing members, wherein the fibrous rovings on the opposite side surfaces of the parallel strips retain their porosity.   
     
     
         2 . The reinforced composite panel of  claim 1 , wherein the at least one layer of helically surrounding fibrous rovings comprises a first layer of fibrous reinforcements wound in a helical manner and a second layer of fibrous reinforcements over the first layer of fibrous reinforcements, wherein the fibrous reinforcements of the second layer cross the fibrous reinforcements of the first layer. 
     
     
         3 . The reinforced composite panel of  claim 1 , wherein the hardened adhesive resin is a hardened thermoset resin. 
     
     
         4 . A reinforced composite panel having an upper side and a lower side comprising:
 a plurality of parallel elongated strips of low density cellular material having parallel opposite side surfaces and parallel opposite faces perpendicular to the side surfaces, wherein the elongated strips are oriented such that the side surfaces face the upper side and the lower side of the reinforced composite panel, wherein the elongated strips comprise at least one layer of helically surrounding fibrous rovings, wherein the fibrous rovings extend over the side surfaces and opposite faces of the elongated strips;   a hardened adhesive resin extending through the fibrous rovings on the opposite faces of the elongated strips forming internal reinforcing members, and   an additional resin extending through the fibrous rovings on the side surfaces of the elongated strips.   
     
     
         5 . The reinforced composite panel of  claim 4 , wherein the at least one layer of helically surrounding fibrous rovings comprises a first layer of fibrous reinforcements wound in a helical manner and a second layer of fibrous reinforcements over the first layer of fibrous reinforcements, wherein the fibrous reinforcements of the second layer cross the fibrous reinforcements of the first layer. 
     
     
         6 . The reinforced composite panel of  claim 4 , further comprising a first skin on the upper surface of the panel adhesively attached to the elongated strips by the additional resin extending through the fibrous rovings on the side surfaces of the elongated strips. 
     
     
         7 . The reinforced composite panel of  claim 4 , wherein the hardened adhesive resin is a hardened thermoset resin. 
     
     
         8 . The reinforced composite panel of  claim 4 , wherein the additional resin is a thermoplastic resin. 
     
     
         9 . A reinforced composite panel having an upper side and a lower side comprising:
 a plurality of parallel elongated strips of low density cellular material having parallel opposite side surfaces and parallel opposite faces perpendicular to the side surfaces, wherein the elongated strips are oriented such that the side surfaces face the upper side and the lower side of the reinforced composite panel, wherein the elongated strips comprise at least one layer of helically surrounding fibrous rovings, wherein the fibrous rovings extend over the side surfaces and opposite faces of the elongated strips;   a hardened adhesive resin extending through the fibrous rovings on the opposite faces of the elongated strips forming internal reinforcing members,   wherein the fibrous rovings adjacent on the opposite side surfaces are substantially free of the hardened adhesive resin.   
     
     
         10 . The reinforced composite panel of  claim 9 , wherein the at least one layer of helically surrounding fibrous rovings comprises a set of braided rovings. 
     
     
         11 . The reinforced composite panel of  claim 9 , wherein the at least one layer of helically surrounding fibrous rovings comprises a first layer of fibrous reinforcements wound in a helical manner and a second layer of fibrous reinforcements over the first layer of fibrous reinforcements, wherein the fibrous reinforcements of the second layer cross the fibrous reinforcements of the first layer. 
     
     
         12 . The reinforced composite panel of  claim 9 , wherein the fibrous reinforcements comprise fiberglass. 
     
     
         13 . The reinforced composite panel of  claim 9 , wherein the hardened adhesive resin is a partially cured thermoset resin. 
     
     
         14 . A reinforced composite panel having an upper side and a lower side comprising:
 a plurality of parallel elongated strips of low density cellular material having parallel opposite side surfaces and parallel opposite faces perpendicular to the side surfaces, wherein the elongated strips are oriented such that the side surfaces face the upper side and the lower side of the reinforced composite panel, wherein the elongated strips comprise at least one layer of helically surrounding fibrous rovings, wherein the fibrous rovings extend over the side surfaces and opposite faces of the elongated strips, and wherein the fibrous rovings comprise a porosity;   a hardened adhesive resin extending through the fibrous rovings on the opposite faces of the elongated strips forming internal reinforcing members such that the fibrous rovings on the opposite faces of the elongated strips retain some porosity,   wherein the fibrous rovings adjacent on the opposite side surfaces are substantially free of the hardened thermoset resin and retain substantially all of their porosity.   
     
     
         15 . The reinforced composite panel of  claim 14 , wherein the at least one layer of helically surrounding fibrous rovings comprises a set of braided rovings. 
     
     
         16 . The reinforced composite panel of  claim 14 , wherein the at least one layer of helically surrounding fibrous rovings comprises a first layer of fibrous reinforcements wound in a helical manner and a second layer of fibrous reinforcements over the first layer of fibrous reinforcements, wherein the fibrous reinforcements of the second layer cross the fibrous reinforcements of the first layer. 
     
     
         17 . The reinforced composite panel of  claim 14 , wherein the fibrous reinforcements comprise fiberglass. 
     
     
         18 . The reinforced composite panel of  claim 14 , wherein the hardened adhesive resin is a hardened thermoset resin. 
     
     
         19 . A reinforced composite panel having an upper side and a lower side comprising:
 a plurality of parallel elongated strips of low density cellular material having parallel opposite side surfaces and parallel opposite faces perpendicular to the side surfaces, wherein the elongated strips are oriented such that the side surfaces face the upper side and the lower side of the reinforced composite panel, wherein the elongated strips comprise at least one layer of helically surrounding fibrous rovings, wherein the fibrous rovings extend over the side surfaces and opposite faces of the elongated strips, and wherein the fibrous rovings comprise a porosity;   a hardened adhesive resin extending through the fibrous rovings on the opposite faces of the elongated strips and extending laterally across a portion of the fibrous rovings on the opposite side surfaces to form a series of structural I-beams,   wherein the fibrous rovings adjacent on the opposite side surfaces outside out the structural I-beams are substantially free of the hardened adhesive resin and retain substantially all of their porosity.   
     
     
         20 . The reinforced composite panel of  claim 19 , wherein the hardened adhesive resin is a hardened thermoset resin. 
     
     
         21 . The reinforced composite panel of  claim 19 , further comprising a first skin on the upper surface of the panel adhesively attached to the elongated strips by an additional resin extending through the fibrous rovings on the side surfaces of the elongated strips.