Lockheed Martin Corporation

Lockheed Corporation

Ronald P Schmidt

Ross A Benson

Larry R Bersuch

Elbert Lee McKague, Jr

Linas N Repecka

Harry R Miller

Todd H Ashton

David Uhl

Gregory W Lundeen

David A Kalser

Richard R Batzer

Amir Islam

John C Macguire

David A Kaiser

Elbert Lee Mckague

GW Lundeen

A three-dimensional, woven metal fiber preform and metal braze matrix forms a high temperature metallic structural joint. The preform is used with a braze alloy matrix to join a structural skin to a flangeless frame. This same basic joint can be used to create large complex structures with very little tooling. The three-dimensional woven metal preform is a flexible element that conforms to match the skin and flangeless frame, thereby avoiding high costs associated with precision fixturing. A high temperature braze metal is used as a matrix for the wire and to join the woven preform to the skin and the frame. The edges of the preform are tapered to a feather edge to avoid stress concentrations and stiffness mismatch.

System, method, and apparatus for three-dimensional woven metal preform structural joint

Composite tooling is fabricated with low cost dry fabrics and a neat resin instead of expensive prepregs. Dry, three-dimensional woven joint preforms are placed on a dry tool substrate and dry, 3D preforms are also placed between pre-cured egg crate-like junctions. The entire tool substrate and substrate-to-support structure joints are then resin-infused simultaneously through the use of rota-molded tooling aids, providing an additional reduction in cost. Tight control of resin content and distribution with vacuum infusion is thereby provided. This process eliminates the primary cause of structural weakness and cooling distortion, which typically occur at the attachment interface when existing methods are used. The preforms provide significantly greater pull-off strengths at interfaces than do hand-laid tie plies. Issues with tool surface durability are addressed through the use of ceramic-filled face coat.

System, method, and apparatus for production-worthy, low cost composite tool fabrication

A method provides for full or partial infusion of resin into three-dimensional, woven textile preforms. Resin film is placed at selected locations adjacent the preform, and the resin film may be separated from other areas of the preform using separator sheets or other materials. The preform is heated and may be vacuum-bagged to apply pressure, or may be rolled or fed through a die. The heat and pressure cause the resin to infuse into the selected areas of the preform adjacent the resin films. The amount of resin in the partial infusion is the same as is necessary to fully infuse the preform, but the resin remains localized in the selected areas until heated again at cure to cause the resin to flow throughout the preform. The method may also be used to fully infuse the preform with resin by providing sufficient temperature and time at that temperature during the initial infusion.

Methods of hot-melt impregnation of 3-D, woven, textile preforms

A preform for structural joints has a three-dimensional weave architecture with fill fibers woven to provide layer-to-layer interlocking of layers of warp fiber as well as interlocking of fibers within each layer. At least two legs extend from a base, the base and legs each having at least two layers of warp fibers. The legs are connected at a symmetrical, distributed-column intersection, with an odd number of columns of warp fibers being located being the legs. The outer ends of the base and legs preferably have tapers formed from terminating layers of warp fibers in a stepped pattern. Tracer fibers that include a colored strand and an x-ray opaque strand are woven into the preform at selected locations as a warp fiber. The tracer fibers allow for identification of a selected location or a selected portion of the preform through visual inspection or by x-ray image.

Woven preform for structural joints

A system and method for forming structural assemblies with 3-D woven joint pre-forms. The method of the present invention forms complex structural assemblies with pre-formed structures. Adhesive is applied between the preformed structures and uncured 3-D woven textile pre-forms. Then together the preformed structures and uncured resin impregnated 3-D woven textile are cured with heat and/or pressure to form the larger complex structural assemblies.

System and method of forming structural assemblies with 3-D woven joint pre-forms

A method for using a three-dimensional, woven preform to assemble two components. The woven preform is infused with an adhesive, and at least one surface of the preform is bonded to at least one surface of one of the components using the adhesive within the preform. The other of the components is attached to the preform, and this may occur with fasteners after the adhesive is cured or by bonding the second component to the preform with the adhesive. Use of an adhesive, instead of a resin, creates a stronger joint, especially with fiber-reinforcement of the adhesive. The thickness of the compressible, three-dimensional weave provides for a larger dimensional tolerance at each bond line.

Adhesive-infused 3-D woven textile preforms for structural joints

A preformed component or &ldquo;preform&rdquo; for a structural member has a planar base with two longitudinal legs extending in parallel from the base. A channel is defined between the legs for insertion of a flat plate that forms the first member of the structural member. The base of the preform is bonded to a composite panel. The preform is a composite material having continuous filaments of woven or braided fiber. The preform is impregnated with a thermoset resin that bonds the first member to the second member of the structural member. The preform may have filaments in the legs having a coefficient of expansion to match the plate, and filaments in the base having a coefficient of expansion to match the panel.

Apparatus and method for joining dissimilar materials to form a structural support member

A three-dimensional weave architecture for weaving preforms has fill fibers woven to provide layer-to-layer interlocking of layers of warp fiber as well as interlocking of fibers within each layer. The woven preform transfers out-of-plane loading through directed fibers to minimize inter-laminar tension. The preform has a base and at least one leg extending from the base, the base and leg each having at least two layers of warp fibers. The fill fibers follow a weave sequence which carries them through part of the base, then into the legs, then through the other portion of the base, and back through the base to return to the starting point of the fill tow. The leg may be connected at a single- or distributed-column intersection, and the intersection may be radiussed. The outer ends of the base and legs may have tapers formed from terminating layers of warp fibers in a stepped pattern.

Three-dimensional weave architecture

Methods of hot-melt resin impregnation of 3-D, woven, textile preforms

A support structure flange preform resembles the Greek letter &ldquo;pi&rdquo; and has a base with two legs extending therefrom. The preform is composed of a composite material that is formed from tows of woven or braided fiber. The tows are oriented to extend throughout each the base and legs. The preform may be either impregnated with a suitable thermoset resin, or may be unimpregnated so that resin may be infused at a later step of the overall manufacturing process. Two of the preforms are joined to a sine wave-shaped web of the structural beam. The web is formed from uncured, thermoset resin sheets that are reinforced with oriented fibers. The web has two outer laminates that sandwich a syntactic or foamed resin layer in between. The legs of each preform straddle one edge of the web and are shaped to both sides to the precise contours of the web. A laminate strip is positioned against the base of each preform to create a pair of flanges for the structural support member. The assembled structure is then heated and cured. The web and/or flanges of the structure also may be configured with alternating beads, tapered in either the vertical or horizontal direction, or inclined at non-orthogonal angles.

Composite material support structures with sinusoidal webs and method of fabricating same

A method and apparatus are disclosed for providing an aircraft thermal protection system for hypersonic cruise and space launch vehicles. A flexible outer skin formed from a metal super alloy is designed to flex and accommodate thermal growth in the vehicle structure. The flexible super alloy skin is made from a plurality of hexagonal shaped cups which are welded together at the edges in a honeycomb type of array with thermal expansion gaps provided between the outermost surfaces of the hexagonal cups. Gap covers extend across the thermal expansion gaps to reduce aerodynamic drag. The flexible outer skin extends over hexagonal shaped, high temperature ceramic blocks, which provide both an insulation layer and support for the outer skin. The flexible outer skin distributes airloads across various ones of the rigid ceramic blocks. A strain isolation pad extends across the ends of the blocks, opposite the flexible outer skin, to absorb strains induced by thermal expansion of the ceramic blocks and the materials beneath. A closed cell foam sheeting extends adjacent to the strain isolation pads, opposite the ceramic blocks, to provide a moisture barrier for preventing liquid formation and freezing on cryogenic fuel tanks. A thin super alloy backing foil extends along the closed cell foam sheeting, opposite the strain isolation pads. The flexible outer skin is secured to the backing foil by super alloy rods.

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Fort Worth, TX, United States of America

Ronald P Schmidt