Textile joint reinforcement and associated method

#The present invention relates to composite textiles assembly, and, more particularly, to reinforcing three dimensional textile joints and support structures in a composite panel.

#The use of composite structures in the aerospace industry has become more and more prevalent due to the desirable properties of composites, especially low weight, high strength and stiffness, resistance to corrosion, and damping characteristics among other properties. Composite materials are now being used for aircraft wings, horizontal and vertical stabilizers, nose and tail cones, and other aircraft structural elements. The advantageous properties of composites have increased aircraft performance benefits, including increased range, decreased fuel consumption, and greater payload. Added performance benefits guide the use of composites throughout the aerospace industry. However, the primary shortcoming of composites has been high cost, which has prohibited the use of composite materials in low cost applications. Cost is now the primary barrier to the use of composite materials in additional applications and the aerospace industry is continuing to explore ways to improve the cost of composite manufacturing while maintaining the performance benefits of composite materials. In particular, assembly of composite structures, especially three dimensional composite structures, has been a significant cost burden in the aerospace industry.

#The assembly of a composite aircraft wing provides an example of the current cost burden. The outer skin of an aircraft wing is typically an assembly of composite panels. Composite panels typically include adhesively bonded lamina of textile fiber and other core materials. The panels are sometimes pre-impregnated with the organic resin matrix (prepreg) and cured in an autoclave, or dry fibers assembled and laid up in a resin transfer mold (RTM) or a vacuum assisted resin transfer mold (VARTM) process, infused with the organic resin and cured in an oven. The composite panels are typically assembled prior to curing, while they are in their flexible textile form. In the final cured product they become an integral rigid structure.

#Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

#FIGS. 1 and 2 are end views of a “T” shaped joint reinforcement stapled to a composite panel according to one embodiment of the present invention;

#FIGS. 3 and 4 are end views of a “pi” shape joint reinforcement stapled to composite panel according to one embodiment of the present invention;

#The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

#According to the present invention, an apparatus and method for composite textile joint reinforcement is provided. As known to those skilled in the art, composite textile structures are strengthened against out of plane forces by three dimensional support structures in a variety of manners. Support structures that are often used to reinforce composite structures include spars, ribs, intercostals, and stringers. Likewise, a variety of joint reinforcement structures are used for reinforcing the connection between the support structure and the composite structure. The present invention is suitable for connecting numerous types of joint reinforcement structures to many different support structures.

#Referring now to FIG. 1, a three dimensional composite preform joint reinforcement 10, shaped like a “T”, is depicted positioned upon a composite panel 12 preform. The term preform refers to composite structures prior to molding and curing to the final rigid composite structure, known in the art as C-stage. The term composite refers to an organic resin matrix of textile fibers such as fibers formed of glass, carbon, boron, Kevlar®, etc. In the course of curing, the organic matrix solidifies about the fibers to form an integral rigid structure. Many curing processes are well known to those skilled in the art and require little explanation to describe the present invention. As will be apparent, however, the present invention is applicable to preforms that are impregnated with organic resin matrix prior to assembly (prepreg) and those that are assembled dry and then impregnated and cured in a resin transfer mold (RTM) process.