Method for making a pin reinforced, crack resistant fiber reinforced composite airfoil

Abstract

A composite article, for example a blading member of a gas turbine engine, comprising a plurality of stacked layers of in-plane reinforcing fibers bonded together with a matrix resin is provided with enhanced resistance to impact cracking, material loss and/or delamination through use of a plurality of spaced apart reinforcing pins disposed into the article at an angle to the stacked layers, in one form disposed in a selected article region generally to resist strain energy generated during operation of the region. In another form, enhanced resistance is provided through the combination of a matrix resin including properties comprising a tensile strain property of at least 5% and a K 1c toughness of at least about 850 psi·inch 1/2 , and a plurality of spaced apart reinforcing pins disposed into the article at an angle to the stacked layers. A method for making such a composite article with such resin comprises stacking the layers of in-plane reinforcing fibers into a shape and then inserting the reinforcing pins shape. The shape is cured with a matrix resin about the in-plane fibers of the stacked layers and about the reinforcing pins.

1 - 29 . (canceled)  
   
   
       30 . A method for making a pin reinforced composite airfoil of a turbine engine blading member comprising plurality of stacked layers of in-plane reinforcing fibers bonded together with a matrix resin and defining a thickness of the article comprising the steps of: 
 providing a plurality of layers of in-plane reinforcing fibers impregnated with a partially cured matrix resin that includes properties comprising a tensile capacity of greater than 5% and a K 1c  toughness of at least about 850 psi˜inch 1/2 ;    stacking the layers one upon another into a stack of layers that at least defines the airfoil;    selecting a plurality of regions about the stack of layers defining the airfoil; and, inserting a plurality of reinforcing pins into the stack of layers at an angle to the stack of layers;    the density of the plurality of reinforcing pins inserted in at least one selected region differs from the density of reinforcing pins inserted in another selected region about the stack of layers generally to balance airfoil strain energy generated during operation of the airfoil.    
   
   
       31 . The method of  claim 30  in which the plurality of selected regions together substantially covers the stack of layers.  
   
   
       32 . The method of  claim 30  in which the density of pins inserted in a selected region is in the range of about ½-5%.  
   
   
       33 . The method of  claim 32  in which the density of pins is in the range of about ½-2%.  
   
   
       34 - 35 . (canceled)  
   
   
       36 . A method for making a pin reinforced composite airfoil of a turbine engine blading member comprising a plurality of stacked layers of in-plane reinforcing fibers bonded together with a matrix resin and defining a thickness of the article comprising the steps of: 
 providing a plurality of layers of in-plane reinforcing fibers;    stacking the layers one upon another into a stack of layers that at least defines the airfoil;    selecting a plurality of regions about the stack of layers defining the airfoil; and,    inserting a plurality of reinforcing pins into the stack of layers at an angle to the stack of layers:    the density of the plurality of reinforcing pins inserted in at least one selected region differs from the density of reinforcing pins inserted in another selected region about the stack of layers generally to balance airfoil strain energy generated during operation of the airfoil.    
   
   
       37 . The method of  claim 36  in which the plurality of selected regions together substantially covers the stack of layers.  
   
   
       38 . The method of  claim 36  in which the density of pins inserted in a selected region is in the range of about ½-5%.  
   
   
       39 . The method of  claim 38  in which the density of pins is in the range of about ½-2%.