One-piece inner shell for full barrel composite fuselage

Abstract

A mandrel for manufacturing a unitary seamless section of an aircraft fuselage comprises a thin lay-up mandrel element disposed onto the outer shell surface of an inner mandrel shell, forming a mandrel with a substantially continuous lay-up surface. A unitary pre-cured section of an aircraft fuselage is formed by laying up a plurality of resin impregnated skin fibers onto the mandrel's lay-up surface while the mandrel rotates.

1 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage comprising:
 a inner mandrel shell having an outer shell surface;   a thin lay-up mandrel element disposable onto said outer shell surface to form a mandrel with a substantially continuous lay-up surface such that when a plurality of resin impregnated skin fibers are laid up onto said lay-up surface, a unitary pre-cured section of an aircraft fuselage is formed.   
     
     
         2 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 1 , wherein said thin lay-up mandrel element comprises a plurality of caul plates. 
     
     
         3 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 1 , further comprising:
 a plurality of stiffener channels formed in said thin lay-up mandrel element, said plurality of stiffener channels adapted to receive a plurality of resin impregnated stiffener fibers.   
     
     
         4 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 3 , further comprising:
 a plurality of rubber mandrels configured to fit into each of said plurality of stiffener channels after laying up said plurality of resin impregnated stiffener fibers.   
     
     
         5 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 1 , further comprising:
 at least one support ring engaged to said thin lay-up mandrel element, said at least one support ring supporting said thin lay-up mandrel element while said cylindrical inner mandrel shell is removed.   
     
     
         6 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 1 , wherein:
 said cylindrical inner mandrel shell comprises a first shell end having a larger shell outer dimension and a second shell end having a smaller shell outer dimension;   said thin lay-up mandrel element comprises a first plate end having a smaller plate inner dimension and a second plate end having a larger plate inner dimension, said thin lay-up mandrel element complementing said cylindrical inner mandrel shell to produce a substantially uniform dimension lay-up surface;   wherein said cylindrical inner mandrel shell and said thin lay-up mandrel element are complemented to facilitate removal of said cylindrical inner mandrel shell.   
     
     
         7 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 1 , further comprising:
 an air source in communication with said cylindrical mandrel inner shell such that said air source forces air in between said thin lay-up mandrel element and said cylindrical inner mandrel shell to facilitate removal of said cylindrical inner mandrel shell.   
     
     
         8 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 1 , further comprising:
 a vibrational source in communication with said cylindrical mandrel inner shell such said vibrational source applies a vibrational load to said thin lay-up mandrel element to facilitate removal of said cylindrical inner mandrel shell.   
     
     
         9 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage comprising:
 a one-piece inner mandrel shell having an outer shell surface;   a plurality of caul plates disposable onto said outer shell surface to form a mandrel with a lay-up surface, said caul plates arranged longitudinally parallel to the longitudinal axis of said one-piece inner mandrel shell and comprising a plurality of longitudinal stiffener channels formed into a caul outer surface; and   a plurality of resin impregnated stiffener fibers disposable within said plurality of stiffener channels such that top ends of said stiffener fibers form a flush mandrel surface, wherein when a plurality of resin impregnated skin fibers are laid up onto said lay-up surface, a unitary pre-cured section of an aircraft fuselage is formed.   
     
     
         10 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 9 , further comprising:
 a plurality of rubber mandrels configured to fit into each of said plurality of stiffener channels after laying up said plurality of resin impregnated stiffener fibers.   
     
     
         11 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 9 , further comprising:
 at least one support ring engaged to said caul plates, said at least one support ring supporting said caul plates while said inner mandrel shell is removed.   
     
     
         12 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 9 , wherein:
 said cylindrical inner mandrel shell comprises a first shell end having a larger shell outer dimension and a second shell end having a smaller shell outer dimension;   said each of said caul plates comprises a first plate end having a smaller plate inner dimension and a second plate end having a larger plate inner dimension, said caul plates complementing said inner mandrel shell to produce a substantially uniform dimension lay-up surface;   wherein said inner mandrel shell and said caul plates are complemented to facilitate removal of said inner mandrel shell.   
     
     
         13 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 9 , further comprising:
 an air source in communication with said inner mandrel shell such that said air source forces air in between said caul plates and said inner mandrel shell to facilitate removal of said inner mandrel shell.   
     
     
         14 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 9 , further comprising:
 a vibrational source in communication with said inner mandrel shell such that said vibrational source applies a vibrational load to said caul plates to facilitate removal of said inner mandrel shell.   
     
     
         15 . A mandrel for use in laying up a unitary pre-cured seamless section of an aircraft fuselage comprising:
 a cylindrical one-piece inner mandrel shell having an outer shell surface;   a plurality of caul plates disposable onto said outer shell surface, said caul plates abutted end-to-end around said outer shell surface to form a contiguous lay-up surface having a plurality of longitudinal stiffener channels formed therein; and   a plurality of resin impregnated stiffener fibers disposable within said plurality of stiffener channels such that top ends of said stiffener fibers are flush with said lay-up surface.   
     
     
         16 . A mandrel for use in laying up a unitary pre-cured seamless section of an aircraft fuselage as described in  claim 15 , wherein the plurality of caul plates are arranged longitudinally parallel to the longitudinal axis of said one-piece inner mandrel shell. 
     
     
         17 . A mandrel for use in laying up a unitary pre-cured seamless section of an aircraft fuselage as described in  claim 15 , wherein said plurality of stiffener channels are adapted to receive a plurality of resin impregnated stiffener fibers. 
     
     
         18 . A mandrel for use in laying up a unitary pre-cured seamless section of an aircraft fuselage as described in  claim 17 , further comprising a plurality of rubber mandrels configured to fit into each of said plurality of stiffener channels after laying up said plurality of resin impregnated stiffener fibers. 
     
     
         19 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 15 , further comprising:
 at least one support ring engaged to said caul plates, said at least one support ring supporting said caul plates while said inner mandrel shell is removed.   
     
     
         20 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 15 , wherein:
 said cylindrical inner mandrel shell comprises a first shell end having a larger shell outer dimension and a second shell end having a smaller shell outer dimension;   said each of said caul plates comprises a first plate end having a smaller plate inner dimension and a second plate end having a larger plate inner dimension, said caul plates complementing said inner mandrel shell to produce a substantially uniform dimension lay-up surface;   wherein said inner mandrel shell and said caul plates are complemented to facilitate removal of said inner mandrel shell.   
     
     
         21 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 15 , further comprising:
 an air source in communication with said inner mandrel shell such that said air source forces air in between said caul plates and said inner mandrel shell to facilitate removal of said inner mandrel shell.   
     
     
         22 . A mandrel for use in manufacturing a unitary seamless section of an aircraft fuselage as described in  claim 15 , further comprising:
 a vibrational source in communication with said inner mandrel shell such that said vibrational source applies a vibrational load to said caul plates to facilitate removal of said inner mandrel shell.