Composite Truss Panel Having Fluted Core

Abstract

A composite truss structure employs a sandwich-in-sandwich construction in which a composite fluted core is sandwiched between two facesheets, and at least one structural foam stiffener is sandwiched within the core or between the facesheets and/or the core.

1 . A composite truss panel, comprising:
 a first and a second composite facesheets;   a fluted core sandwiched between the first and second facesheets; and   at least one stiffener between the first and second facesheets formed of low density structural foam.   
     
     
         2 . The composite truss panel of  claim 1 , wherein:
 the low density structural foam is a high temperature foam having a density between approximately 2 and 6 pounds per cubic foot.   
     
     
         3 . The composite truss panel of  claim 1 , wherein:
 the at least one stiffener is sandwiched between the first facesheet and the fluted core.   
     
     
         4 . The composite truss panel of  claim 1 , further comprising:
 a second stiffener formed of low density structural foam and sandwiched between the second facesheet and the fluted core.   
     
     
         5 . The composite truss panel of  claim 1 , wherein the first and second facesheets diverge relative to each other. 
     
     
         6 . The composite truss panel of  claim 1 , wherein:
 the fluted core includes walls extending between the first and second facesheets, and   the at least one stiffener member is sandwiched between adjacent ones of the walls.   
     
     
         7 . The composite truss panel of  claim 1 , wherein:
 the fluted core includes a plurality of hollow flutes joined together and allowing a gas to pass therethrough.   
     
     
         8 . The composite truss panel of  claim 1 , wherein the at least one stiffener extends substantially parallel to the first and second facesheets. 
     
     
         9 . The composite truss panel of  claim 1 , wherein the at least one stiffener extends in a direction from the first facesheet to the second facesheet. 
     
     
         10 . A composite truss panel, comprising:
 a first sandwich including first and second facesheets and a fluted core sandwiched between and joined to the first and second facesheets; and   a second sandwich disposed within the first sandwich, the second sandwich including at least one structural foam stiffener.   
     
     
         11 . The composite truss panel of  claim 10 , wherein:
 the at least one structural foam stiffener is formed from a high temperature foam having a density between approximately 2 and 6 pounds per cubic foot.   
     
     
         12 . The composite truss panel of  claim 10 , wherein:
 the fluted core includes walls extending between the first and second facesheets, and   the second sandwich includes adjacent ones of the walls of the fluted core.   
     
     
         13 . The composite truss panel of  claim 10 , wherein:
 the at least one stiffener is sandwiched between the fluted core and one of the first and second facesheets.   
     
     
         14 . A composite truss panel, comprising:
 first and second composite facesheets;   a fluted core sandwiched between the first and second facesheets, the fluted core including a plurality of composite flutes, the flutes being generally hollow and having walls extending traverse to the first and second facesheets; and   low density structural foam stiffeners between the walls of adjacent ones of the flutes; and,   a low density structural foam stiffener between the fluted core and at least one of the first and second facesheets.