Monolithic hurricane resistant structural panels made from low density composites

Abstract

A three dimensional composite panel structure is provided having a thickness less than about 22.5 cm, overall density less than 0.2 g/cm, and exhibiting a global modulus greater than 1.2 GPa and stiffness greater than 15 kN-m 2 . The composite panel structure includes at least two fiber-reinforced mats interconnected in a spaced substantially parallel configuration by a skeletal web and a closed cell foam filling the spaces between the panels. The fiber-reinforced mats include a plurality of fibers in a low viscosity cured thermosetting resin matrix.

1 . A three dimensional composite panel structure having a thickness less than about 22.5 cm, overall density less than 0.2 g/cm, and exhibiting a global modulus greater than 1.2 GPa and stiffness greater than 15 kN-m 2 , the composite panel structure comprising: 
 (a) at least two fiber-reinforced mats interconnected in a spaced substantially parallel configuration by a skeletal web; and    (b) a closed cell foam filling the spaces between said fiber-reinforced mats;    wherein said fiber-reinforced mats comprise a plurality of fibers in a low viscosity cured thermosetting resin matrix.    
   
   
       2 . The three dimensional composite panel structure of  claim 1  wherein said panel is sized and shaped to form a unitary roof panel for a building.  
   
   
       3 . The three dimensional composite panel structure of  claim 2  wherein said thermosetting resin is natural resin, a synthetic resin, or a combination thereof.  
   
   
       4 . The three dimensional composite panel structure of  claim 2 , wherein the material of said resin is Acrylated Epoxidized Soybean Oil.  
   
   
       5 . The three dimensional composite panel structure of  claim 2  wherein said closed cell foam is natural, synthetic, or combinations thereof.  
   
   
       6 . The three dimensional composite panel structure of  claim 2  wherein said composite panel comprises resin in an amount of between about 30 and 40 wt %, fiber-reinforced mats in an amount of between about 20 and 40 wt %, and foam in an amount of between about 30 and 40 wt % of the total composite weight.  
   
   
       7 . The three dimensional composite panel structure of  claim 2 , wherein the material of said fibers is natural.  
   
   
       8 . The three dimensional composite panel structure of  claim 7 , wherein the material of said fibers is flax, hemp, pulp, cellulose, or chicken feathers.  
   
   
       9 . The three dimensional composite panel structure of  claim 2 , wherein the material of said fibers is synthetic.  
   
   
       10 . The three dimensional composite panel structure of  claim 9 , wherein the material of said fibers is glass, carbon, or poly-paraphenylene terephthalamide.  
   
   
       11 . A method of making a three dimensional composite panel structure having a thickness less than about 22.5 cm, overall density less than 0.2 g/cm, and exhibiting a global modulus greater than 1.2 GPa and stiffness greater than 15 kN-m 2 , the method comprising the steps of: 
 placing a composite panel preform in a one-sided mold;    vacuum bagging the composite panel preform;    applying a uniform negative pressure over the entire composite panel preform utilizing a vacuum at one side of the preform;    drawing resin into the composite panel preform;    permeating resin into all parts of the composite structure;    curing the resin at room temperature;    maintaining the composite panel under vacuum to improve consolidation;    increasing the composite mechanical properties and fiber content by reducing void percentage; and    demolding the composite panel.    
   
   
       12 . A method for making a hurricane resistant roof for a building, the method comprising forming said roof with a three dimensional composite panel sized and shaped to form said roof, said three dimensional composite panel structure having a thickness less than about 22.5 cm, overall density less than 0.2 g/cm, and exhibiting a global modulus greater than 1.2 GPa and stiffness greater than 15 kN-m 2 , the method comprising forming said three dimensional panel by: 
 placing a composite panel preform in a one-sided mold;    vacuum bagging the composite panel preform;    applying a uniform negative pressure over the entire composite panel preform utilizing a vacuum at one side of the preform;    drawing resin into the composite panel perform, said resin being a natural resin, a synthetic resin, or a combination thereof;    permeating resin into all parts of the composite structure;    curing the resin at room temperature;    maintaining the composite panel under vacuum to improve consolidation;    increasing the composite mechanical properties and fiber content by reducing void percentage; and    demolding the composite panel.    
   
   
       13 . The method of  claim 12  wherein said perform comprises flax, hemp, pulp, cellulose, chicken feathers, and combinations thereof.  
   
   
       14 . The method of  claim 13  wherein said resin is Acrylated Epoxidized Soybean Oil.