Turbine engine with composite blade

Abstract

A blade for a turbine engine comprising a composite core defining a pressure side and a suction side extending axially between a leading edge and a trailing edge defining a chord-wise direction and extending radially between a root and a tip defining a span-wise direction. The composite core is formed from two materials with different compositions.

What is claimed is: 
     
         1 . An airfoil for a turbine engine, the airfoil comprising:
 a composite core having a pressure side and a suction side extending axially between a leading edge and a trailing edge defining a chord-wise direction and extending radially between a root and a tip defining a span-wise direction and having a span-length;   a first portion of the composite core extending radially from the root less than 100% of the span-length and formed from a first material;   a second portion of the composite core proximate the first portion and defining at least a portion of the tip and formed from a second material, having a lower strain capability than the first material and having a different composition than the first material.   
     
     
         2 . The airfoil of  claim 1  wherein the first material is a compliant material having a strain capability greater than or equal to 1% and the second material is a less compliant material having a strain capability less than or equal to 1%. 
     
     
         3 . The airfoil of  claim 1  wherein the second material has a strain capability that is less than 85% of the strain capability of the first material. 
     
     
         4 . The airfoil of  claim 1  wherein the second portion extends radially from the first portion up to 5% of the span-length. 
     
     
         5 . The airfoil of  claim 1  wherein the second material has a modulus of elasticity greater than 10 Msi. 
     
     
         6 . The airfoil of  claim 1  wherein the first material has a modulus of elasticity between 5 Msi and 20 Msi. 
     
     
         7 . The airfoil of  claim 1  further comprising a fuse between the first portion and the second portion to define a frangible zone. 
     
     
         8 . The airfoil of  claim 7  wherein the fuse is one of a scarfed, interwoven, butt, or lap joint. 
     
     
         9 . The airfoil of  claim 1  further comprising a tip cap extending along at least a portion of the tip. 
     
     
         10 . The airfoil of  claim 9  wherein the tip cap extends along at least 50% of the tip in the chord-wise direction. 
     
     
         11 . The airfoil of  claim 10  wherein the tip cap extends along 100% of the tip. 
     
     
         12 . The airfoil of  claim 1  wherein at least one of the first or second materials are composite materials. 
     
     
         13 . The airfoil of  claim 12  wherein the second material is an epoxy fiber material. 
     
     
         14 . The airfoil of  claim 1  further comprising a leading edge strip formed from at least two different materials. 
     
     
         15 . The airfoil of  claim 14  wherein the leading edge strip comprises a leading edge frangible zone. 
     
     
         16 . A blade for a turbine engine, the blade comprising:
 interior composite core having a pressure side and a suction side extending axially between a leading edge and a trailing edge defining a chord-wise direction and extending radially between a root and a tip defining a span-wise direction and having a span-length;   a first portion of the composite core extending radially from the root less than 100% of the span-length and formed from a first material;   a second portion of the composite core proximate the first portion and defining at least a portion of the tip and formed from a second material having a lower strain capability than the first material and a different composition than the first material.   
     
     
         17 . The blade of  claim 16  wherein the second material has a strain capability that is less than 85% of the strain capability of the first material. 
     
     
         18 . The blade of  claim 16  wherein the second material has a modulus of elasticity greater than 10 Msi. 
     
     
         19 . The blade of  claim 16  wherein the first material has a modulus of elasticity between 5 Msi and 20 Msi. 
     
     
         20 . The blade of  claim 16  further comprising a fuse between the first portion and the second portion to define a frangible zone. 
     
     
         21 . The blade of  claim 20  wherein the fuse is one of a scarfed, interwoven, butt, or lap joint. 
     
     
         22 . The blade of  claim 16  further comprising a tip cap extending along at least a portion of the tip. 
     
     
         23 . The blade of  claim 16  wherein at least one of the first or second materials are composite materials. 
     
     
         24 . The airfoil of  claim 16  further comprising a leading edge strip formed from at least two different materials. 
     
     
         25 . The airfoil of  claim 24  wherein the leading edge strip comprises a leading edge frangible zone. 
     
     
         26 . A method for forming a blade having composite core and extending radially between a root and a tip defining a span-wise direction and having a span-length, the method comprising:
 forming a first and a second portion of the composite core;   extending the first portion radially outward from the root less than 100% of the span-length;   extending the second portion radially inward from the tip to meet the first portion; and   joining the first portion to the second portion to form a fuse.   
     
     
         27 . The method of  claim 26  wherein forming the fuse includes one of a scarfing, interweaving, abutting, or lapping the first portion to the second portion. 
     
     
         28 . The method of  claim 26  further comprising extending a tip cap around at least a portion of the tip. 
     
     
         29 . The method of  claim 26  wherein forming the second portion includes forming the second portion from a stiff non-compliant material. 
     
     
         30 . The method of  claim 26  further comprising forming a leading edge strip having a first portion made and a second portion made from a material different than the material from which the first portion is made and having a lower modulus of elasticity than the first portion.