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

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 - 23 . (canceled)  
   
   
       24 . A method for making a pin reinforced composite article 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 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;    selecting at least one article region of the stack of layers in which a plurality of reinforcing pins are to be disposed; and,    inserting the plurality of reinforcing pins into the stack of layers at an angle to the stack of layers.    
   
   
       25 . The method of  claim 24  in which the pins are disposed within a selected region at a density of pins that resists strain energy generated during operation of the region.  
   
   
       26 . The method of  claim 25  in which the pins are disposed substantially uniformly across a region.  
   
   
       27 . The method of  claim 24  in which: 
 the in-plane reinforcing fibers in a layer substantially are aligned with one another; and,    the reinforcing pins are inserted substantially completely through the thickness of the article.    
   
   
       28 . The method of  claim 25  in which: 
 the layers of the in-plane reinforcing fibers are stacked in a supporting fixture to provide a stack of layers;    the reinforcing pins are inserted into the stack of layers to provide a preform;    the preform is placed in a curing mold cavity;    the mold cavity is closed;    a vacuum is provided within the mold cavity about the preform of the layers and the reinforcing pins; and,    the matrix resin is cured about the in-plane fibers and reinforcing pins.    
   
   
       29 . The method of  claim 28  in which the partially cured matrix resin is cured at a temperature in the range of about 350-400° F.  
   
   
       30 - 39 . (canceled)