Abstract:
Rib and spar webs are joined in a composite wingbox to eliminate fasteners by welding the webs along bond lines defined by overlapping sections of the webs. Heat to produce the weld is generally achieved resistively by connecting a multistrip susceptor positioned along the bond line to a current source, since the geometry makes it difficult to heat these web joints inductively. The wingbox is completed without fasteners by welding skins to the rib-spar wingbox.
Abstract:
Sesceptor sheets are selected so that their magnetic permeability decreases to unity at approximately the desired operating temperature thereby limiting heating to this "Curie temperature" and providing substantial uniformity of temperature in the panel Preferably, the susceptor includes multiple layers, such as a first metal having a relatively lower Curie temperature, a thin foil of copper in contact with the surface of the first sheet, and a second metal having a relatively higher Curie temperature. Such a susceptor allows thermal control at two spaced set points defined by the Curie temperatures.
Abstract:
For forming or consolidating organic matrix composites, for example, an organic matrix composite panel is sealed between sheets of a susceptor material that is susceptible to induction heating. The susceptor sheets are heated inductively. The sheets in turn conduct heat to the organic matrix composite panel. When heated to the desired temperature, the composite panel is consolidated and/or formed. In the present invention, the susceptor sheets are selected so that their magnetic permeability decreases to unity at approximately the desired operating temperature thereby limiting heating to this "Curie temperature" and providing substantial uniformity of temperature in the panel. Of course, the concept applies to other induction heating operations for metals including SPF, brazing, annealing, heat treating, bonding, hot pressing, and the like.
Abstract:
A fiber reinforcement fabric contains a metal susceptor strip paired with each warp thread and woven with the weave thread to produce a thermoplastic welding susceptor of separated and electrically isolated, longitudinal metal strips and fiber reinforcement in the weld.
Abstract:
Our induction heating workcell permits rapid and controlled heating and cooling of a workpiece within a wide temperature range. The induction workcell allows us to combine manufacturing operations, like SPF, brazing, and annealing, into a single heating cycle to save time, energy, capital, touch labor, and factory space. Superplastic forming (SPF) and brazing occur at temperatures that differ by about 150.degree.-200.degree. F. (85.degree.-105.degree. C.) or more as do SPF and .beta.-annealing of titanium. We can combine these operations into an economical single cycle in which both operations are done during a single heating of the press Multisheet SPF parts with braze joints at selected locations are made by (a) heating a multisheet pack to its superplastic forming range below the melting point of the braze alloy, (b) superplastically forming the pack at the SPF temperature to form the sheets and to define braze joints having unmelted braze alloy, (c) increasing the temperature to the braze temperature of the braze alloy, and (d) cooling the pack below the superplastic range to freeze the braze alloy in the braze joint.
Abstract:
Apparatus and method for superplastic forming. The workpiece is held between a pair of dies that are electrically and thermally nonconductive, and is heated inductively by a coil embedded within the dies.
Abstract:
A process for brazing a metal face sheet to a honeycomb core to form a composite member. A brazing alloy is placed between the face sheet and the core. Rigid thermal insulation is used to press the face sheet against the core while heating the structure with induction heating for a time just sufficient to melt the brazing alloy. The portion being brazed is covered by an inert gas when it is at elevated temperatures. The rapid heating and cooling of the brazing alloy by induction heating joins the face sheet to the core without excessive energy consumption or the need for a complex vacuum system.
Abstract:
A composite induction consolidation apparatus includes a base mandrel and a ferromagnetic base mandrel facesheet having a specific Curie temperature carried by the base mandrel. The base mandrel facesheet is adapted to support a composite part and allow ambient air pressure to compact the composite part against the base mandrel facesheet. At least one magnetic induction coil is provided in the base mandrel.
Abstract:
In an embodiment of the disclosure, there is provided a molybdenum composite hybrid laminate. The laminate has a plurality of composite material layers. The laminate further has a plurality of surface treated molybdenum foil layers interweaved between the composite material layers. The laminate further has a plurality of adhesive layers disposed between and bonding adjacent layers of the composite material layers and the molybdenum foil layers.
Abstract:
A doubler repair apparatus includes a composite structure having a repair area, a susceptor having an adhesive film and at least one magnetic component extending within the adhesive film on the repair area, a repair doubler patch on the susceptor and a heat source having an induction coil generally above the repair doubler patch.