초록 ▼

An aircraft structural panel ( 10 ) of the skin-stiffener type such as is commonly used in aircraft construction, has a skin ( 15 ) supported by uniformly spaced stiffeners or frames ( 39 ). Stiffeners ( 39 ) are secured to skin ( 15 ) and extend outwardly from the associated skin ( 15 ). Each stiff

An aircraft structural panel ( 10 ) of the skin-stiffener type such as is commonly used in aircraft construction, has a skin ( 15 ) supported by uniformly spaced stiffeners or frames ( 39 ). Stiffeners ( 39 ) are secured to skin ( 15 ) and extend outwardly from the associated skin ( 15 ). Each stiffener ( 39 ) has a horizontal body ( 38 ), an inner mounting flange ( 41 ), and an outer bowed flange ( 42 ). Mounting flange ( 41 ) and bowed flange ( 42 ) have free edges and respective inturned beads or curls ( 44, 46 ) are formed thereon for stiffening of flanges ( 41 ) and ( 42 ).

대표청구항 ▼

1. An aircraft structural panel comprising:a sheet skin portion;an elongate stiffener secured to said sheet skin portion, said stiffener defining in cross section a web and a flange extending outwardly at each extreme of said web, each of the flanges having a free edge; anda tubular bead extending a

1. An aircraft structural panel comprising:a sheet skin portion;an elongate stiffener secured to said sheet skin portion, said stiffener defining in cross section a web and a flange extending outwardly at each extreme of said web, each of the flanges having a free edge; anda tubular bead extending along the free edge of each flange for reinforcing said stiffener; wherein the tubular beads are inturned and of an elliptical cross section with a minor axis that is at least about 40 percent of the major axis. 2. An aircraft structural panel as defined in claim 1, wherein one of said flanges extends at right angels to said wed to define a mounting flange, and the other of said flanges is a bowed flange. 3. An aircraft structural panel as defined in claimed claim 2, wherein the width of said bowed flange and said mounting flange is each at least about two times the outer diameter of said tubular bead extending along the free edge of the respective flange. 4. An aircraft structural panel as defined in claim 1, wherein said inturned tubular beads are a circular cross-section and extend in a circular path of at least about 210 degrees. 5. An aircraft structural panel as defined in claim 3, wherein said web has a width between two times and seven times the width of said bowed flange and the width of said mounting flange. 6. The aircraft structural panel as defined in claim 1, wherein said inturned tubular beads are of a circular cross-section and extend in a circular path of at least about 270 degrees. 7. The aircraft structural panel as defined in claim 1, further comprising:an intermediate connecting section between said web and one of said flanges, said connecting section extending from said web at an angle of at least about 25 degrees. 8. An aircraft structural panel comprising:an aircraft panel skin having a curved shape and defining an inner surface and an outer surface;a plurality of generally parallel elongate stringers each extending along the inner surface of said panel skin and extending outwardly from said panel skin;a plurality of generally parallel elongate curved stiffeners each aligned to be substantially transverse to a longitudinal axis of an elongate stringer;said stiffeners defining in cross section a web and a flange extending outwardly from each end of said web, each of the flanges having a free edge; anda tubular bead extending along the free edge of each flange for reinforcing said stiffeners, wherein the tubular beads are inturned and of an elliptical cross section with a minor axis that is at least about 40 percent of the major axis. 9. An aircraft structural panel as defined in claim 8, further comprising;a plurality of stringer ties extending between and secured to said stringers and said stiffeners. 10. An aircraft structural panel as defined in claim 8, further comprising;a plurality of shear ties extending between and secured to said aircraft panel skin and said stiffeners. 11. An aircraft structural panel as defined in claim 10, wherein said shear ties are angle shaped having a pair of legs, one of said legs being secured to said aircraft panel skin and the other leg being secured to said stiffeners. 12. An aircraft structural panel as defined in claim 9, wherein at least one flange of each stiffener is planar and extends in a perpendicular relation to said web to define a mounting flange that is adjacent to said stringers. 13. An aircraft structural panel as defined in claim 9, wherein said stringer ties are generally channel shaped including a web and opposed flanges along the web, said web being secured to said stiffeners and said flanges are secured to said stringers. 14. An aircraft structural panel as defined in claim 11, wherein said shear ties are of a curved shape in conforming to the curved shape of said aircraft panel skin and are mounted between said stringers. 15. A structural panel for use on an aircraft fuselage comprising:a plurality of generally parallel spaced elongate structural frames ;a plurality of generally parallel spaced stringers attached to said frames and extending in perpendicular relation to the longitudinal axes of said frames;a skin extending over and attached to said frames and said stringers;said frames defining in cross section a web and a flange extending outwardly at each end of said web, each of the flanges having a free edge; anda tubular bead extending along the free edge of each flange for reinforcing said frames; wherein the tubular beads are inturned and of an elliptical cross section with a minor axis that is at least about 40 percent of the major axis. 16. An aircraft structural panel comprising:a sheet skin portion;an elongate stiffener secured to said sheet skin portion, said stiffener defining in cross section a web and a flange extending outwardly at each extreme of said web, each of the flanges having a free edge; anda tubular bead extending along the free edge of each flange for reinforcing said stiffener, wherein each bead has a closed end to define an enclosed area; and a curled end portion of said bead extends within said enclosed area from said closed end to provide additional reinforcement. 17. The aircraft structural panel as defined in claim 16, wherein said curled end portion is of an elliptical cross section. 18. The aircraft structural panel as defined in claim 16, wherein said curled end portion includes a planar flange extending within said enclosed area. 19. An aircraft structural panel comprising:an aircraft panel skin having a curved shape and defining an inner surface and an outer surface, a plurality of generally parallel elongate stringers extending along the inner surface of said panel skin;a plurality of generally parallel elongate curved stiffeners aligned to be transverse to the longitudinal axes of said stringers;said stiffeners defining in cross section a web and a flange extending outwardly from each end of said web, each of the flanges having a free edge; anda tubular bead extending along the free edge of each flange for reinforcing said stiffener; wherein at least one of said flanges is a bowed flange. 20. A structural panel for use on an aircraft fuselage comprising:a plurality of generally parallel spaced structural frames;a plurality of generally parallel spaced stringers attached to said frames and extending in perpendicular relation thereto;a skin extending over and attached to said frames and said stringers;said frames defining in cross section a web and a flange extending outwardly at each end of said web, each of the flanges having a free edge; anda tubular bead extending along the free edge of each flange for reinforcing said frames; wherein at least one of said flanges is a bowed flange. 21. An aircraft structural panel comprising:a sheet skin portion;an elongate stiffener secured to said sheet skin portion, said stiffener defining in cross section a web and a flange extending outwardly at each extreme of said web, each of the flanges having a free edge; anda tubular bead extending along the free edge of each flange for reinforcing said stiffener wherein at least one of the tubular beads is inturned and of an elliptical cross section with a minor axis that is at least about 40 percent of the major axis. 22. The aircraft structural panel as defined in claim 21, further comprising;an intermediate connecting section between said web and one of said flanges, said connecting section extending from said web at an angle of at least about 25 degrees.