Incremental Stretch Forming.
Abstract
The incremental stretch forming concept involves the forming of large titanium aircraft panels to compound curvatures by applying tension to their long direction and traversing a heat source along them while they are strained over a die. The method has inherent economic advantages over alternative forming methods. The objective of this program was to determine the suitability of the method on actual aircraft panels and to define the limits of panel complexity for which it is applicable. Because early feasibility work shown that contour deviations in the nature of buckles and excessive curvature would commonly result, it was necessary to focus attention on process control parameters by analytical studies before conducting forming trials. A forming process model was developed and provided guidance in the design and construction of the ISF equipment. The model was also the basis for the selection of process control conditions and the developemnt of a forming plan that would make maximum use of the limited number of panels available. Phase I trails involved panels formed over a 6-foot ceramic die with widths up to 22 inches. Tapered, stiffened, pocketed, as well as simple rectangular cross section panels were formed. Generally, satisfactory contours were achieved due to their low senstivity to buckling by thermal stresses. The larger Phase II panels, which had a width of 36 inches and were formed over a 12-foot die, required a higher level of thermal control to minimize contour deviations. With present equipment, control was adequate to prevent buckling but not to eliminate overforming. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1972
- Accession Number
- AD0902943
Entities
People
- Elmer J. Seese
- Harold Switzky
- Theodore A. Renshaw