Collapsible Mandrel Tools and Associated Methods for Fabrication of Wound Composite Articles

Abstract

Mandrels of various configuration, and action, including collapsible mandrels, to be used in forming composite articles with preselected three dimensional shapes and construction are disclosed and described. In one aspect, such a mandrel may have a plurality of discrete segments coupled about a longitudinal axis and collectively forming an enclosure with a substantially continuous exterior working surface. The working surface can have a network of intersecting grooves formed therein, and such grooves can cooperatively establish a substantially continuous interconnected lattice corresponding to the three dimensional geometric configuration to be imparted to a composite article formed. The mandrel may optionally include a removable core assembly to aid in collapse of the mandrel.

1 . A mandrel comprising:
 a plurality of soft discrete segments formed of a polymer and having a substantially flat configuration coupled about a longitudinal axis and collectively forming an enclosure with a substantially continuous exterior working surface, said working surface having a network of intersecting grooves formed therein, said grooves cooperatively establishing a substantially continuous interconnected lattice corresponding to a three dimensional geometric configuration to be imparted to a composite article formed using the mandrel; and   a removable core assembly occupying an interior volume of the enclosure and coupling the segments together to form the enclosure, wherein said plurality of soft discrete segments conform to said removable core.   
     
     
         2 . The collapsible mandrel of  claim 1 , wherein the exterior working surface of the enclosure forms a predetermined shape that matches a shape intended for the composite article. 
     
     
         3 . The collapsible mandrel of  claim 2 , wherein the shape includes a cross-section perpendicular to the longitudinal axis with a geometric form selected from the group consisting of: a circle, an oval, an ellipse, a crescent, a triangle, a square, a rectangle, a pentagon, a hexagon, a heptagon, an octagon, a polygon, a star, and combinations thereof. 
     
     
         4 . (canceled) 
     
     
         5 . (canceled) 
     
     
         6 . (canceled) 
     
     
         7 . The collapsible mandrel of  claim 1 , wherein the shape includes a cross-section perpendicular to the longitudinal axis with a geometric form of a cylinder. 
     
     
         8 . The collapsible mandrel of  claim 1 , wherein the network of intersecting grooves includes intersection of longitudinal grooves with lateral grooves. 
     
     
         9 . The collapsible mandrel of  claim 1 , wherein the network of intersecting grooves includes intersection of longitudinal grooves with helical grooves. 
     
     
         10 . The collapsible mandrel of  claim 1 , wherein the network of intersecting grooves includes intersection of lateral grooves with helical grooves. 
     
     
         11 . The collapsible mandrel of  claim 1 , wherein the network of intersecting grooves includes intersection of longitudinal, lateral, and helical grooves at a single intersection. 
     
     
         12 . The collapsible mandrel of  claim 1 , wherein the grooves each have a predetermined cross-section shape corresponding to a cross-section shape intended for individual supports contained in the composite article. 
     
     
         13 . (canceled) 
     
     
         14 . (canceled) 
     
     
         15 . The collapsible mandrel of  claim 12 , wherein the cross-section shape is widest at a top portion of the groove and a narrowest at a bottom portion of the groove. 
     
     
         16 . (canceled) 
     
     
         17 . (canceled) 
     
     
         18 . The collapsible mandrel of  claim 15 , wherein the bottom portion of the groove is rounded. 
     
     
         19 . The collapsible mandrel of  claim 15 , wherein the groove shape is a member selected from the group consisting of: a T shape with a flange at the top portion of the groove, a rectangle, a square, a triangle with a single vertex at the bottom portion of the groove, a half circle, a trapezoid with two obtuse angles at the bottom portion of the groove, a half pentagon with two obtuse angles at the bottom portion of the groove, a half hexagon with two obtuse angles at the bottom portion of the groove, and a half octagon with three obtuse angles at the bottom portion of the groove. 
     
     
         20 . The collapsible mandrel of  claim 19 , wherein the angles of the shapes at the bottom of the grooves are rounded rather than having a sharp vertex. 
     
     
         21 . (canceled) 
     
     
         22 . The collapsible mandrel of  claim 1 , wherein the interconnected lattice of grooves is a broken lattice extending around only a portion of the enclosure. 
     
     
         23 . (canceled) 
     
     
         24 . (canceled) 
     
     
         25 . (canceled) 
     
     
         26 . (canceled) 
     
     
         27 . (canceled) 
     
     
         28 . (canceled) 
     
     
         29 . (canceled) 
     
     
         30 . (canceled) 
     
     
         31 . The collapsible mandrel of  claim 1 , further comprising a lubricant coating coated over at least a portion of the working surface. 
     
     
         32 . (canceled) 
     
     
         33 . The collapsible mandrel of  claim 1 , wherein the removable core assembly is a single piece. 
     
     
         34 . The collapsible mandrel of  claim 1 , wherein the removable core assembly comprises a multiple integrated pieces. 
     
     
         35 . (canceled) 
     
     
         36 . (canceled) 
     
     
         37 . (canceled) 
     
     
         38 . (canceled) 
     
     
         39 . A method of shaping a fiber-based composite material to be consolidated into a three dimensional structure, comprising:
 providing a mandrel as recited in  claim 1 ;   filling the grooves with a composite material;   consolidating the composite perform material into a three dimensional structure substantially corresponding to the geometric configuration cooperatively established by the grooves; and   removing the mandrel from within the consolidated structure.   
     
     
         40 . A shaped fiber-based composite material assembly comprising:
 a mandrel as recited in  claim 1 ; and   a fiber-based composite material filling the grooves of the interconnected lattice.