Composite Structure and Method for Inspecting a Pre-bond Surface of a Composite Structure

Abstract

A composite structure may include a composite substrate, the composite substrate including a surface, a peel ply, the peel ply including a surface, and an identifiable marking agent, wherein the surface of the peel ply includes the identifiable marking agent, and wherein the peel ply is connected to the composite substrate such that the identifiable marking agent is in contact with the surface of the composite substrate.

1 . A composite structure comprising:
 a composite substrate, said composite substrate comprising a surface;   a peel ply, said peel ply comprising a surface; and   an identifiable marking agent,   wherein said surface of said peel ply comprises said identifiable marking agent, and   wherein said peel ply is connected to said composite substrate such that said identifiable marking agent is in contact with said surface of said composite substrate.   
     
     
         2 . The composite structure of  claim 1  wherein said identifiable marking agent is applied onto said surface of said peel ply. 
     
     
         3 . The composite structure of  claim 2  wherein said identifiable marking agent comprises ink. 
     
     
         4 . The composite structure of  claim 3  wherein said peel ply comprises a fabric layer, and wherein said ink is applied to at least a portion of a surface of said fabric layer. 
     
     
         5 . The composite structure of  claim 3  wherein said ink comprises a resin based ink compatible with said fabric layer. 
     
     
         6 . The composite structure of  claim 3  wherein said ink comprises a thickness, said thickness being approximately between 50 nm and 100 nm. 
     
     
         7 . The composite structure of  claim 3  wherein said ink is applied onto said surface of said peel ply in a grid pattern. 
     
     
         8 . The composite structure of  claim 1  wherein said identifiable marking agent is incorporated into said surface of said peel ply. 
     
     
         9 . The composite structure of  claim 8  wherein said identifiable marking agent comprises a plurality of tracer filaments. 
     
     
         10 . The composite structure of  claim 9  wherein said peel ply comprises a fabric layer, and wherein said plurality of tracer filaments are woven into said fabric layer to define at least a portion of said surface of said peel ply. 
     
     
         11 . A peel ply structure comprising:
 a peel ply, said peel ply comprising a surface; and   an identifiable marking agent,   wherein said surface of said peel ply comprises said identifiable marking agent.   
     
     
         12 . The peel ply structure of  claim 11  wherein said identifiable marking agent is applied onto said surface of said peel ply. 
     
     
         13 . The peel ply structure of  claim 12  wherein said peel ply comprises a fabric layer, wherein said identifiable marking agent comprises ink, and wherein said ink is applied onto at least a portion of a surface of said fabric layer. 
     
     
         14 . The peel ply structure of  claim 11  wherein said identifiable marking agent is incorporated into said surface of said peel ply. 
     
     
         15 . The peel ply structure of  claim 14  wherein said peel ply comprises a fabric layer, wherein said identifiable marking agent comprises a plurality of tracer filaments, and wherein said plurality of tracer filaments are woven into said fabric layer to define at least a portion of said surface of said peel ply. 
     
     
         16 . A method for inspecting a pre-bond surface of a composite structure, said method comprising:
 providing a peel ply, said peel ply comprising a surface, and said surface of said peel ply comprising an identifiable marking agent;   placing said peel ply on a surface of a composite substrate, wherein said surface of said peel ply is in contact with said surface of said composite substrate;   co-curing said peel ply and said composite substrate;   removing said peel ply from said composite substrate to form a modified surface of said composite substrate; and   inspecting said composite substrate for said identifiable marking agent transferred to said modified surface,   wherein said identifiable marking agent is evidence of residue transferred from said peel ply to said composite substrate.   
     
     
         17 . The method of  claim 16  comprising:
 ablating said modified surface to remove said identifiable marking agent and said residue; and 
 inspecting said modified surface after said ablating step for said identifiable marking agent. 
 
     
     
         18 . The method of  claim 16  comprising applying said identifiable marking agent onto said surface of said peel ply. 
     
     
         19 . The method of  claim 18  wherein said applying step comprises applying ink onto at least a portion of a surface of a fabric layer of said peel ply. 
     
     
         20 . The method of  claim 16  comprising incorporating said identifiable marking agent into said surface of said peel ply. 
     
     
         21 . The method of  claim 20  wherein said incorporating step comprises weaving a plurality of tracer filaments into a fabric layer of said peel ply to define at least a portion of said surface of said peel ply.