Mechanical Interlock Feature for Multi-Material Airfoils

Abstract

An airfoil of a first parent material and a second wrap material wherein the parent and wrap materials are of at least partially different materials and wherein an interlock region is formed between the parent and wrap materials having an interlock feature.

What we claim is: 
     
         1 . A mechanical interlock for a multi-material airfoil, comprising:
 a first airfoil portion connectable to a rotor disk, said first airfoil portion being formed of a first material;   said first airfoil portion having an interlock feature extending therefrom;   a second airfoil portion connected to said interlock feature of said first airfoil portion, said second airfoil portion extending from said first airfoil portion in a radial direction;   said second airfoil portion formed of at least a partially dissimilar material.   
     
     
         2 . The mechanical interlock for a multi-material airfoil of  claim 1  wherein said first material is a first composite. 
     
     
         3 . The mechanical interlock of  claim 2  wherein one of said interlock feature is an inverted dovetail. 
     
     
         4 . The mechanical interlock of  claim 3  wherein said first material includes a plurality of continuous fibers extending from a lower portion of said first airfoil portion into said inverted dovetail. 
     
     
         5 . The mechanical interlock of  claim 1  wherein said second airfoil portion is a second composite dissimilar from said first composite. 
     
     
         6 . The mechanical interlock of  claim 1  wherein said second airfoil portion is one of a cast-able foam or a polyurethane. 
     
     
         7 . The mechanical interlock of  claim 1  further comprising a cladding material overlapping said first airfoil portion and said second airfoil portion. 
     
     
         8 . A mechanical interlock for a multi-material airfoil, comprising:
 a leading edge, a trailing edge, a shank end and an opposed tip;   a parent connectable to a rotor disk, said parent being formed of a first material and having an interlock feature extending in a radial upward direction;   a wrap being formed of at least a partially different material than said first material, said wrap defining said opposed tip;   said wrap having a cavity for receiving said interlock feature;   said wrap extending from said parent in a radial direction.   
     
     
         9 . The mechanical interlock of  claim 8 , said interlock feature being an inverted dovetail. 
     
     
         10 . The mechanical interlock of  claim 9 , said inverted dovetail having angled surfaces. 
     
     
         11 . The mechanical interlock of  claim 9 , said inverted dovetail having a varying thickness extending along a length of said airfoil. 
     
     
         12 . The mechanical interlock of  claim 8 , said interlock feature having continuous fibers integrally formed between the parent material and the dovetail. 
     
     
         13 . The mechanical interlock of  claim 8 , said parent material and said wrap material being differing materials. 
     
     
         14 . The mechanical interlock of  claim 8  further comprising a cladding between said parent material and said wrap material. 
     
     
         15 . A mechanical interlock for a multi-material airfoil, comprising:
 a first airfoil portion formed of a first material and having an interlock feature extending in a radially upward direction;   a second airfoil portion formed of a second material wherein said second material is at least partially different than said first material, said second airfoil portion extending from said first airfoil portion in a radial direction;   said second airfoil portion having a cavity receiving said interlock feature;   said first airfoil and said second airfoil portions defining an interlock region wherein said interlock feature and said interlock cavity are disposed.   
     
     
         16 . The mechanical interlock of  claim 15 , said interlock feature being an inverted dovetail. 
     
     
         17 . The mechanical interlock of  claim 16 , said first material including continuous fibers extending from a radially lower end of said first airfoil portion into said interlock feature. 
     
     
         18 . The mechanical interlock of  claim 15 , said first material and said second material being composite materials. 
     
     
         19 . The mechanical interlock of  claim 15  further comprising a cladding extending across said interlock region. 
     
     
         20 . The mechanical interlock of  claim 15  wherein characteristics of said interlock feature may be varied in a spanwise direction.