British Aerospace Public Limited Company

British Aerospace Plc

David Stephen

Martin H Mansbridge

John Norton

David J Irwin

Alan W Highnam

The present invention provides a method of making a domed structure using superplastic forming and diffusion bonding techniques. The dome is of a deep and/or irregular shape that cannot be achieved by creep forming. The method includes the step of forming a stack of two or more sheets made of superplastic material and the sheets of the stack being joined together in face to face contact by metallic bonds such that no sheet in the stack is bonded to more than one of its neighbouring sheets; the metallic bonds preferably lie on lines extending radially from and/or circumferentially around the said peak. The resulting stack is heated to superplastic termperatures and a pressure differential is established across the stack to form it into a domed shape. The resulting dome is placed in a mould and heated; an inert gas is injected between the sheets to inflate the stack superplastically thereby forming a space between the sheets which is divided into cells by webs formed from two of the said sheets that have been superplastically formed by the inflation process.

Domed structures and a method of making them by superplastic forming and

A structural box beam of the type formed by a method using superplastic forming and diffusion bonding techniques (SPF/DB). The basis is a SPF/DB four sheet cellular structure box beam, for particular application to a flap track beam for aircraft, said box beam including integrally formed flap track flanges and corrugated shear webs. The corrugations serve the dual purpose of reacting local track bending moments. Internal shear webs are integrally formed as part of the cellular structure. The box beam is designed to be manufactured from a flat blank assembly consisting of four chemically-etched sheets with local reinforcements placed between the core and skin sheets providing a low cost means of tailoring the beam to minimum thickness requirements.

Structural box beams

A stiffened panel of the type formed by a method including subjecting two metal sheets, both capable of superplastic deformation and diffusion bonding, which are positioned face to face, to a bending and deforming process during which the sheets are joined to one another at a series of spaced substantially continuous joint lines across their faces, and during which parts of said sheets between the joint lines are superplastically deformed in a mould to form a series of cavities between the two sheets, portions of said sheets on respective sides of a joint line being moved to form sidewalls of two neighboring cavities, these sidewalls being urged to lie adjacent one another over substantial parts of their areas, so that they become diffusion bonded one to another to form a common sidewall of neighboring cavities, and having formed spaced-apart regions where the sheets have contacted opposite mould faces is further formed with an outer lip region in which an edged region of one sheet remains generally aligned with that spaced-apart region which it forms, while an edge region of the other sheet is deformed out of alignment with that spaced-apart region which it forms to lie, firstly, generally transverse to the spaced-apart regions and, secondly, to be generally aligned with, and be attached to, said region of said one sheet.

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Bristol, United Kingdom

David Stephen