초록 ▼

A method of forming an aircraft nacelle nose lip segment. The method includes bending a sheet of metal into a substantially U-shaped workpiece having a spanwise axis, opposed first and second ends, and opposed first and second edges. The method further includes placing the workpiece over a substant

A method of forming an aircraft nacelle nose lip segment. The method includes bending a sheet of metal into a substantially U-shaped workpiece having a spanwise axis, opposed first and second ends, and opposed first and second edges. The method further includes placing the workpiece over a substantially flexible first mandrel, stretching the workpiece in a spanwise direction between the first and second ends, and wrapping the workpiece and first mandrel together about a curved die while stretching the workpiece. The workpiece is thereby plastically deformed to have a first shape. The method may further include removing the workpiece from the first mandrel, and placing the workpiece over a substantially rigid second mandrel that substantially corresponds in shape to the first shape of the workpiece. The workpiece is stretched over the second mandrel in a chordwise direction that is substantially transverse to the spanwise axis of the workpiece, thereby further plastically deforming the workpiece.

대표청구항 ▼

What is claimed is: 1. A method of forming an aircraft nacelle inlet noselip segment, the method comprising: (a) shaping a sheet of metal into a substantially U-shaped workpiece having a spanwise axis, opposed first and second ends, and opposed first and second edges; (b) placing the shaped workpie

What is claimed is: 1. A method of forming an aircraft nacelle inlet noselip segment, the method comprising: (a) shaping a sheet of metal into a substantially U-shaped workpiece having a spanwise axis, opposed first and second ends, and opposed first and second edges; (b) placing the shaped workpiece on a substantially flexible first mandrel; (c) stretching the workpiece in a spanwise direction between the first and second ends while bending the workpiece and first mandrel together about a die, whereby the workpiece is plastically deformed to have a first shape; (d) removing the workpiece from the first mandrel; (e) placing the workpiece over a substantially rigid second mandrel that substantially corresponds in shape to the first shape of the workpiece; and (f) stretching the workpiece over the second mandrel between the first and second edges in a chordwise direction that is substantially transverse to the spanwise axis of the workpiece, whereby the workpiece is further plastically deformed to have a second shape. 2. A method according to claim 1, and further comprising annealing the workpiece before placing the workpiece over the substantially rigid second mandrel and before stretching the workpiece over the second mandrel. 3. A method according to claim 1, and further comprising crimping the first end of the workpiece to form a first gripping portion, and crimping the second end of the workpiece to form a second gripping portion. 4. A method according to claim 1 and further comprising: (a) crimping the first end to form a first gripping portion, and crimping the second end to form a second gripping portion; and (b) removing the first and second gripping portions from the workpiece before stretching the workpiece over the second mandrel. 5. A method according to claim 1, comprising stretching the workpiece over the first mandrel having a plurality of interconnected segments. 6. A method according to claim 1, comprising stretching the workpiece over a bendable and substantially incompressible first mandrel. 7. A method according to claim 1 comprising stretching the first workpiece in the spanwise direction on a skin press machine. 8. A method according to claim 1, and further comprising trimming the workpiece to a final shape. 9. A method according to claim 1, wherein: (a) the first mandrel comprises a polymeric material; (b) the first mandrel substantially corresponds in shape to the first shape when the first mandrel is in an unrestrained state; and (c) wherein the method further comprises reshaping the first mandrel to substantially correspond in shape to the U-shaped workpiece before placing the workpiece over the first mandrel. 10. A method according to claim 1 and further comprising age hardening the workpiece after stretching the workpiece over the second mandrel. 11. A method of forming compound curvatures in a metal sheet, the method comprising: (a) bending the metal sheet about a first mandrel having a spanwise axis to form a channel; (b) plastically stretching the channel in a spanwise direction while substantially simultaneously bending the channel and first mandrel about a second mandrel, the second mandrel having a curvature that is non-parallel to the spanwise axis of the first mandrel. 12. A method according to claim 11 and further comprising further plastically stretching the channel in a direction that is substantially transverse to the spanwise direction. 13. A method according to claim 11, and further comprising annealing the channel after plastically stretching the channel. 14. A method according to claim 12, and further comprising age hardening the channel after further plastically stretching the channel. 15. A method according to claim 11 wherein the first mandrel comprises a plurality of interconnected segments. 16. A method according to claim 11, wherein the first mandrel comprises a flexible polymeric material. 17. A method according to claim 11, wherein the first mandrel comprises a bendable and substantially incompressible material. 18. A method according to claim 11 wherein the spanwise stretching is performed on a skin press machine. 19. A method according to claim 12 wherein further plastically stretching the channel in a direction that is substantially transverse to the spanwise direction comprises stretching the channel about a third mandrel. 20. A stretch-forming method for producing metal skin segments having compound curvatures, the method comprising: (a) forming a sheet of metal into a curved channel having a spanwise first axis of curvature; (b) plastically stretching the channel in a spanwise direction while substantially simultaneously bending the channel about a second axis of curvature; and (c) plastically stretching the channel in a direction that is substantially transverse to the spanwise first axis after plastically stretching the channel in a spanwise direction. 21. A method according to claim 20, and further comprising annealing the channel after plastically stretching and bending the channel. 22. A method according to claim 20, and further comprising age hardening the channel after stretching the channel in a direction that is substantially transverse to the spanwise first axis. 23. A method according to claim 20, wherein the method yields an aircraft nacelle inlet nose lip segment.