Fibre reinforced polymer composite pipes

Abstract

A fiber reinforced polymer composite pipe includes first and second ends and defines a central axis running in a longitudinal direction from the first end to the second end, and the pipe including at least one non-linear portion along the central axis between the first end and the second end. A first material extends continuously from the first end to the second end, the first material being a fiber reinforced polymer material comprising fiber reinforcement in a polymer matrix and having an electrical resistivity determined by an electrically conductive fiber reinforcement and/or an electrically conductive additive in the polymer matrix; and a second material arranged at the at least one non-linear portion and extending discontinuously between the first end and the second end, and has an elastic modulus greater than the elastic modulus of the first material in the longitudinal direction.

What is claimed is: 
     
         1 . A method of making a fiber reinforced polymer composite pipe comprising:
 providing a mold cavity shaped to form a pipe having a first end, a second end, and at least one non-linear portion between the first end and the second end;   placing one or more fiber preforms in the mold cavity to form the fiber reinforcement of a first material extending continuously from the first end to the second end;   placing one or more carbon fiber preforms in the mold at the at least one non-linear portion to form the fiber reinforcement of a second material extending discontinuously between the first end and the second end; and   filling the mold cavity with a polymer matrix material to form the first material as a fiber reinforced polymer material comprising fiber reinforcement in a polymer matrix and the second material as a carbon fiber reinforced polymer material comprising carbon fiber reinforcement in a polymer matrix.   
     
     
         2 . The method of  claim 1 , wherein the first material has an electrical resistivity determined by an electrically conductive fiber reinforcement or an electrically conductive additive in the polymer matrix. 
     
     
         3 . The method of  claim 1 , wherein an elastic modulus of the second material is greater than an elastic modulus of the first material in the longitudinal direction. 
     
     
         4 . The method of  claim 1 , wherein the first material is formed by automated fiber placement (AFP). 
     
     
         5 . The method of  claim 1 , wherein the first material is formed by filament winding of the fiber reinforcement. 
     
     
         6 . The method of  claim 1 , wherein the first material is formed by resin transfer moulding (RTM), using a braided preform for the fiber reinforcement. 
     
     
         7 . The method of claim, further comprising:
 forming the second material by filament winding of the carbon fiber reinforcement.   
     
     
         8 . The method of  claim 1 , comprising forming the second material by automated fiber placement (AFP). 
     
     
         9 . The method of  claim 1 , comprising forming the second material by braiding continuous carbon fiber reinforcement so as to achieve one or more desired fiber angles. 
     
     
         10 . The method of  claim 9 , further comprising:
 interweaving groups of continuous carbon fibers into a triaxially braided tube comprising a first group of continuous carbon fibers extending substantially along the central axis of the pipe, a second group of continuous carbon fibers extending at an angle of +50-85 degrees relative to the central axis of the pipe, and a third group of continuous carbon fibers extending at an angle of −50-85 degrees relative to the central axis of the pipe.   
     
     
         11 . The method of  claim 1 , comprising forming the second material at the same time as the first material. 
     
     
         12 . The method of  claim 11 , comprising forming both the first material and the second material in a single RTM process. 
     
     
         13 . The method of  claim 1 , wherein the first material takes the form of an inner pipe or an outer pipe. 
     
     
         14 . The method of  claim 1 , wherein the second material is formed as a layer on the inside or the outside of the first material. 
     
     
         15 . The method of  claim 1 , wherein the mould cavity is shaped to form a pipe with a plurality of non-linear portions between the first end and the second end, and the method comprises placing carbon fiber preforms in the mould at each of the non-linear portions.