Stringers made of a composite material with a bulb

Abstract

The invention relates to a stringer ( 11, 21, 31 ) made of a composite material for stiffening panels made of a composite material, particularly those used in the aeronautics industry, formed by a foot ( 15 ) for joining with the panel and a structural member ( 13, 23, 33 ) with a structural reinforcement ( 17, 27, 37 ) embedded at the end opposite to the foot ( 15 ) formed by high-modulus unidirectional fibers of the same material as the stringer or another material compatible with it. The invention also relates to a process of manufacturing the stringer.

1 . A stringer ( 11 ,  21 ,  31 ) of a composite material for stiffening panels made of a composite material formed by a foot ( 15 ) for joining with the panel and a structural member ( 13 ,  23 ,  33 ), characterized in that at the end opposite to the foot ( 15 ) and between plies of material, the structural member ( 13 ,  23 ,  33 ) includes a structural reinforcement ( 17 ,  27 ,  37 ) formed by high-modulus unidirectional fibers made of the same material as the stringer or another material that is compatible with it.  
     
     
         2 . A stringer ( 11 ) according to  claim 1 , characterized in that it has a T shape, the structural member being formed by a web ( 13 ), and in that the reinforcement ( 17 ) is arranged such that the end part ( 19 ) has a rounded bulb shape.  
     
     
         3 . A stringer ( 21 ) according to  claim 1 , characterized in that it has an I shape, the structural member ( 23 ) being formed by a web ( 24 ) and two side flanges ( 25 ,  26 ), and in that the reinforcement ( 27 ) is arranged between plies of the side flanges ( 25 ,  26 ) such that the latter have an elongated bulb shape.  
     
     
         4 . A stringer ( 31 ) according to  claim 1 , characterized in that it has a J shape, the structural member ( 33 ) being formed by a web ( 34 ) with a side flange ( 35 ), and in that the reinforcement ( 37 ) is arranged between plies of the side flange ( 35 ) such that the latter has an elongated bulb shape.  
     
     
         5 . A process of manufacturing a stringer according to  claim 1 , characterized in that it comprises the following steps: 
 a) providing a planar laminate made of a composite material formed by plies of carbon fiber or fiberglass, with thermosetting or thermoplastic resin;    b) appropriately forming the planar laminate, according to the desired stringer shape;    c) introducing the reinforcement;    d) giving the stringer its final shape.    
     
     
         6 . The process of manufacturing a stringer according to  claim 5 , characterized in that: 
 in step b) the planar laminate ( 41 ) is formed to become a T-shaped stringer defining the two parts ( 43 ,  45 ) that will form the foot ( 15 ) and the two parts ( 47 ,  49 ) that will form the web ( 13 );    in step c) the reinforcement ( 17 ) is introduced between parts ( 47 ,  49 ) of the web ( 13 );    in step d) the stringer is given its final shape with the end part ( 19 ) in a rounded bulb shape.    
     
     
         7 . A process of manufacturing a stringer according to  claim 2 , characterized in that it comprises the following steps: 
 a) providing a planar laminate made of a composite material formed by plies of carbon fiber or fiberglass, with thermosetting or thermoplastic resin;    b) appropriately forming the planar laminate, according to the desired stringer shape;    c) introducing the reinforcement;    d) giving the stringer its final shape.    
     
     
         8 . A process of manufacturing a stringer according to  claim 3 , characterized in that it comprises the following steps: 
 a) providing a planar laminate made of a composite material formed by plies of carbon fiber or fiberglass, with thermosetting or thermoplastic resin;    b) appropriately forming the planar laminate, according to the desired stringer shape;    c) introducing the reinforcement;    d) giving the stringer its final shape.    
     
     
         9 . A process of manufacturing a stringer according to  claim 4 , characterized in that it comprises the following steps: 
 a) providing a planar laminate made of a composite material formed by plies of carbon fiber or fiberglass, with thermosetting or thermoplastic resin;    b) appropriately forming the planar laminate, according to the desired stringer shape;    c) introducing the reinforcement;    d) giving the stringer its final shape.    
     
     
         10 . The process of manufacturing a stringer according to  claim 7 , characterized in that: 
 in step b) the planar laminate ( 41 ) is formed to become a T-shaped stringer defining the two parts ( 43 ,  45 ) that will form the foot ( 15 ) and the two parts ( 47 ,  49 ) that will form the web ( 13 );    in step c) the reinforcement ( 17 ) is introduced between parts ( 47 ,  49 ) of the web ( 13 ),    in step d) the stringer is given its final shape with the end part ( 19 ) in a rounded bulb shape.    
     
     
         11 . The process of manufacturing a stringer according to  claim 8 , characterized in that: 
 in step b) the planar laminate ( 41 ) is formed to become a T-shaped stringer defining the two parts ( 43 ,  45 ) that will form the foot ( 15 ) and the two parts ( 47 ,  49 ) that mill form the web ( 13 );    in step c) the reinforcement ( 17 ) is introduced between parts ( 47 ,  49 ) of the web ( 13 ),    in step d) the stringer is given its final shape with the end part ( 19 ) in a rounded bulb shape.    
     
     
         12 . The process of manufacturing a stringer according to  claim 9 , characterized in that: 
 in step b) the planar laminate ( 41 ) is formed to become a T-shaped stringer defining the two parts ( 43 ,  45 ) that will form the foot ( 15 ) and the two parts ( 47 ,  49 ) that will form the web ( 13 );    in step c) the reinforcement ( 17 ) is introduced between parts ( 47 ,  49 ) of the web ( 13 ),    in step d) the stringer is given its final shape with the end part ( 19 ) in a rounded bulb shape.