Sandwich structure and associated pressure-based forming method

Abstract

A formed sandwich structure manufactured by a pressure-based forming method that includes steps of (1) positioning a sandwich structure into a cavity of a die assembly, the sandwich structure including a core positioned between a first liner sheet and a second liner sheet, the core including a honeycomb structure having a plurality of cells, and (2) after the positioning, pressurizing the core to expand the sandwich structure into engagement with the die assembly.

What is claimed is: 
     
         1 . A formed sandwich structure manufactured by a pressure-based forming method comprising:
 positioning a sandwich structure into a cavity of a die assembly, said sandwich structure comprising a core positioned between a first liner sheet and a second liner sheet, said core comprising a honeycomb structure comprising a plurality of cells; and   after said positioning, pressurizing said core to expand said sandwich structure into engagement with said die assembly.   
     
     
         2 . The formed sandwich structure of  claim 1  wherein said core comprises a plurality of apertures, and wherein said plurality of apertures provide fluid communication between said plurality of cells of said honeycomb structure. 
     
     
         3 . The formed sandwich structure of  claim 1  wherein said sandwich structure comprises a fluid port in fluid communication with an open volume defined by said core. 
     
     
         4 . The formed sandwich structure of  claim 1  wherein said pressurizing said core comprises introducing a fluid into said core. 
     
     
         5 . The formed sandwich structure of  claim 1  wherein said pressure-based forming method further comprises heating said sandwich structure to a temperature of at least 100° C. 
     
     
         6 . The formed sandwich structure of  claim 5  wherein said temperature is at least 400° C. 
     
     
         7 . The formed sandwich structure of  claim 5  wherein said heating said sandwich structure is performed concurrently with said pressurizing said core. 
     
     
         8 . The formed sandwich structure of  claim 5  wherein said sandwich structure is formed from a metallic material having a recrystallization temperature, and wherein said temperature is at least said recrystallization temperature. 
     
     
         9 . The formed sandwich structure of  claim 1  wherein said pressure-based forming method further comprises mechanically deforming said sandwich structure prior to positioning said sandwich structure into said cavity. 
     
     
         10 . The formed sandwich structure of  claim 9  wherein said pressure-based forming method further comprises annealing said sandwich structure after said mechanically deforming said sandwich structure. 
     
     
         11 . A formed sandwich structure comprising:
 a core comprising a first major side and a second major side, said core further comprising a honeycomb structure comprising a plurality of cells, wherein said core has been rendered superplastic and stretched while superplastic;   a first liner sheet connected to said first major side of said core; and   a second liner sheet connected to said second major side of said core.   
     
     
         12 . The formed sandwich structure of  claim 11  wherein each cell of said plurality of cells is tubular and extends continuously through said core from said first liner sheet to said second liner sheet. 
     
     
         13 . The formed sandwich structure of  claim 11  wherein each cell of said plurality of cells extends along an axis that is generally perpendicular to a plane coincident with an outer surface of said first liner sheet. 
     
     
         14 . The formed sandwich structure of  claim 11  wherein each cell of said plurality of cells has a hexagonal cross-sectional shape. 
     
     
         15 . The formed sandwich structure of  claim 11  wherein a cross-sectional thickness of said core is at least 2 times thicker than a cross-sectional thickness of said first liner sheet. 
     
     
         16 . The formed sandwich structure of  claim 11  wherein said core comprises a plurality of apertures, and wherein said plurality of apertures provide fluid communication between said plurality of cells of said honeycomb structure. 
     
     
         17 . The formed sandwich structure of  claim 16  wherein said core further comprises an open volume defined by said plurality of cells and said plurality of apertures. 
     
     
         18 . The formed sandwich structure of  claim 11  wherein said first major side of said core is uniformly bonded to said first liner sheet and said second major side of said core is uniformly bonded to said second liner sheet. 
     
     
         19 . The formed sandwich structure of  claim 18  wherein each cell of said plurality of cells is enclosed by both said first liner sheet and said second liner sheet. 
     
     
         20 . The formed sandwich structure of  claim 11  wherein said core has been pneumatically stretched while superplastic.