Method of Manufacturing Aircraft Engine Parts Utilizing Reusable And Reconfigurable Smart Memory Polymer Mandrel

Abstract

A method for fabricating aircraft engine external target parts including complex geometries utilizes reusable reconfigurable shape memory polymer and conformable woven braided carbon fiber sleeves. The method includes providing a tubular three-dimensional reusable shape memory polymer mandrel assembly designed for a target part, and heating the shape memory polymer mandrel.

What is claimed is: 
     
         1 . A method for fabricating aircraft engine external target parts including complex geometries utilizing reusable reconfigurable shape memory polymer and conformable woven braided carbon fiber sleeves, the method comprising:
 providing a tubular 3-dimensional reusable shape memory polymer mandrel assembly designed for a target part (Part C);   providing conformable woven braided carbon fiber sleeves;   providing a high temperature resin system formulated for carbon fiber;   covering the shape memory polymer mandrel with a release agent;   applying a first layer of braided carbon fiber sleeve, to the shape memory polymer mandrel, using the high temperature resin system for wetting and adhesion;   using said resin system to overlay subsequent wetted layers to the shape memory polymer mandrel, to create the final formed carbon composite tube which replicates Part C; and,   heating the shape memory polymer mandrel until its temperature exceeds the glass transition temperature of the shape memory polymer, and the shape memory polymer becomes compliant and elastic, and then, removing the elastic shape memory polymer and separating it from the newly formed Part C.   
     
     
         2 . The fabrication method of  claim 1 , wherein, after separation, the shape memory polymer mandrel is cleaned, reheated, and placed in the tooling shape mold for re-forming and reuse. 
     
     
         3 . The fabrication method of  claim 1 , wherein a subsequent higher temperature resin cure is performed, on Part C, after removal of the reusable polymer tool. 
     
     
         4 . The fabrication method of  claim 1 , wherein the high temperature resin system, formulated for carbon fiber, further comprises an optional vacuum bag system to remove excess resin. 
     
     
         5 . The fabrication method of  claim 1 , wherein Part C is a low temperature tube or duct. 
     
     
         6 . The fabrication method of  claim 1 , wherein said fluid delivery parts are parts of an aerospace system. 
     
     
         7 . The fabrication method of  claim 1 , wherein said fluid delivery parts are external aircraft engine parts. 
     
     
         8 . The fabrication method of  claim 1 , wherein said fluid delivery parts are parts of a turbine. 
     
     
         9 . The fabrication method of  claim 1 , wherein the target parts include complex cylindrical and non-cylindrical tube geometries with non-uniform cross-sectional size (tapering). 
     
     
         10 . The fabrication method of  claim 1 , wherein the target part geometries include complex transitions from cylindrical to rectangular cross-sectional shapes. 
     
     
         11 . The fabrication method of  claim 1 , wherein, depending on loads and boundary conditions, multiple local properly orientated braided sleeves are applied to increase direction strength at high stress locations. 
     
     
         12 . The fabrication method of  claim 1 , wherein Part C is a mounting bracket, fan house casing, or support. 
     
     
         13 . The fabrication method of  claim 1 , wherein complex geometry tubes are formed before the thermoset resin is applied and cured, thereby obviating post-bending and joining. 
     
     
         14 . The fabrication method of  claim 1 , wherein the carbon fiber sleeves are properly sized for the target part.