Systems, tools, and methods for forming composite tubular stringers and stiffened composite structures having composite tubular stringers

摘要

Systems, tools, and methods for forming composite tubular stringers and stiffened composite structures having composite tubular stringers are disclosed. Systems include a tool, a supply of pliable blanks for forming composite tubular stringers with the tool, a supply of skin segments for forming a skin, and a layup mandrel for receiving the composite tubular stringers and the skin to form a stiffened composite structure. Tools include a wrapping mandrel for forming from a pliable blank a tubular structure with a first circumferential profile, and a transition mandrel for conforming the tubular structure to a second circumferential profile. Methods include wrapping a pliable blank around a wrapping mandrel to define a tubular structure having a first circumferential profile, and transitioning the tubular structure from having the first circumferential profile to having a second circumferential profile.

主权项

1. A method of forming a composite tubular stringer, the method comprising:
wrapping a pliable blank around a wrapping mandrel to define a tubular structure having a first circumferential profile with a continuous perimeter, wherein the pliable blank is constructed of multiple layers of pre-preg sheets of partially cured fiber reinforced composite material; following the wrapping, transitioning the tubular structure from having the first circumferential profile to having a second circumferential profile that is different from the first circumferential profile to thereby define the composite tubular stringer, wherein the transitioning includes translating the tubular structure from around the wrapping mandrel to around a cure mandrel that is separate from the wrapping mandrel, wherein the cure mandrel has a cure-mandrel outer surface with a generally uniform perpendicular cross-sectional cure-mandrel shape that corresponds to the second circumferential profile of the tubular structure, and wherein the cure mandrel is selectively positioned relative to the wrapping mandrel for receipt of the tubular structure and to selectively carry the tubular structure from relative to the wrapping mandrel to a layup mandrel for subsequent assembly and curing of a stiffened composite structure; and operatively loading the composite tubular stringer together with the cure mandrel on the layup mandrel.