Abstract: A method and apparatus for irrigating perforations in the surface of a perforated material during surface treatment operations. The apparatus includes a three-layer substrate of predetermined length including a first fluid-interactive layer, a second resilient layer, and a third rigidifying layer. In the method, the substrate is placed beneath the perforated surface to be treated with the perforated material overlying the first layer. Thereafter, the surface treatment tool is used to apply and remove pressure to and from the surface during performance of the surface treatment operation. In this way, as the surface is treated, fluid applied to the surface during the operation is caused to pass back and forth to and from the first layer and through the perforations to irrigate the perforations and thereby keep them from becoming clogged.

Abstract: A method and apparatus for effecting superplastic forming of metal workpieces at temperatures greater than 1000.degree. C., wherein both oxidation and creep deformation of the tooling are minimized. The process is achieved by heating forming surfaces of ceramic forming dies to temperatures in excess of 1000.degree. C., and using metal housings to impart high loading conditions to seal the workpiece within a chamber for superplastic forming. More specifically, the metal housings are used not only for load bearing purposes, but also for creating an evacuated chamber within which superplastic forming can take place. The ceramic dies, on the other hand, are positioned on opposing sides of the workpiece region to be superplastically formed, and are insulated from, while being contained within, the metallic dies.

Abstract: The invention is a failure detecting system including fiber optic cables of different lengths disposed in the vicinity of a secured region between two or more adherends, and an electro-optical analysis circuit for analyzing signals detected by the fiber optic cables. The fiber optic cables extend transversely across the connected adherends, with each cable extending a different length so that the width of the structure is divided into discrete regions. In this way, the measurable strain can be integrated over the entire length of the fiber where the fiber remains bonded to the material. The cables are coupled to laser circuitry, detector circuitry and network analyzer circuitry, and signals from the cables are processed in the network analyzer circuitry using a Fast Fourier Transform to reduce complex frequency information to time domain representation of reflection pulses. Thereafter, they are compared with reference signals to indicate the presence and degree of disbond.

Abstract: A fastener system for securing a multi-layer panel having a first surface adapted to be secured to a substructure, a second surface awash in a fluid flowing thereacross, and a plurality of spaced fastener-receiving holes arranged in a predetermined array in the second surface. Each fastener includes a threaded shank having a diameter smaller than any of the fastener-receiving holes, a load-bearing flange located adjacent the shank having a diameter greater than the shank diameter for pressing the first surface of the panel against the substructure, an unthreaded shank extending away from the load-bearing flange and having a diameter smaller than the threaded shank diameter, and a second flange having a diameter greater than the diameter of the load-bearing flange. The second flange is located on the side of the unthreaded shank opposite the load-bearing flange, and functions to seat against a recessed region of the second surface of the panel.

Abstract: A method and apparatus for applying heat sufficient to permit plastic deformation of intermetallic material. The heat is applied to a fractional region of a workpiece, and then manipulations capable of causing the workpiece to deform are applied using conventional sheet metal forming equipment. The invention utilizes elevated forming temperatures to heat the fractional region of the intermetallic workpiece so that the fractional region has sufficient ductility to permit a plastic deformation required for the forming operation. The apparatus is a sheet metal-working machine which has been modified to provide the localized heating required to carry out the process of the present invention.

Abstract: A retort for use in diffusion bonding preselected areas of a stack of metallic sheets during a process of fabricating metallic sandwich structures. The retort facilitates a contamination-free, evacuated environment in which a plurality of sheets of titanium aluminide can be joined to one another at selected areas to form a pack. The process of joining embraces a technique of elevated temperature gas diffusion bonding. Subsequent superplastic expansion of the bonded blanks is employed to form desired sandwich structures.

Abstract: Optimum strengthening of a superplastically formed aluminum-lithium alloy structure is achieved via a thermal processing technique which eliminates the conventional step of solution heat-treating immediately following the step of superplastic forming of the structure. The thermal processing technique involves quenching of the superplastically formed structure using static air, forced air or water quenching.

Abstract: A boundary layer control device including a rotating cylinder mounted on a shaft disposed along the trailing edge of the wing of an aircraft and a flap structure secured to the shaft on which the rotating cylinder is mounted. In the preferred embodiment, the flap structure is coupled to the shaft by brackets, each of which having one end pivoted about the shaft and an opposite end to which the flap is pivotally supported. This arrangement facilitates rotation of the flap structure between a first "cruise" position in which the flap structure is disposed substantially horizontally at the trailing edge of the wing, and a second "VTOL" position in which the flap is disposed either above or below the wing in a "stowed" or aerodynamically hidden position. Various other embodiments are disclosed.

Abstract: A sealant membrane for preventing leakage of fluids from fluid-containing tanks and a method of application of the membrane. The membrane is deposited in a varying thickness atop surfaces of interconnected wall panels in the tank by spray application of successive coats of a sealant material, so that the coating thickness is a maximum where the greatest structural deflections can occur. The successive coats are applied with a predetermined lapse time between layers to prevent slumping of the sealant material.

Abstract: Dummy needles are used for preventing closure of gas-conveying passageways communicating the interior, and provided at the peripery, of a multi-sheet stack of titanium alloy materials during diffusion bonding. After the diffusion bonding has been carried out, the dummy needles fitted within the passageways are removed, the passageways are reamed out to ensure their circular shape, and needles adapted for superplastic forming are inserted into the newly reamed passageways.

Abstract: The invention resides in the fabrication of a structural element comprising a laminated composite having one portion or layer comprising alpha-phase titanium aluminide and another adjacent portion or layer comprising gamma-phase titanium aluminide. Preferably, the gamma-phase portion or layer is joined with the alpha-phase portion or layer by such processes as hot-spraying, diffusion bonding, or vapor deposition. The invention contemplates the utilization of the structural element in the fabrication of the wall of a container or tank for storage of the hydrogen fuel material, where the gamma-phase titanium aluminide portion or layer is oriented so as to be placed in direct contact with the hydrogen fuel material, or at the least be oriented toward any hydrogen leak path.

Abstract: A method for fabricating of intermetallic titanium aluminide sandwich structures in which blanks of titanium aluminide are bonded to one another, under vacuum in a retort, at selected areas to form a pack, and then, upon removal of the retort, expanded superplastically to form a desired sandwich structure. Bonding of the various preselected areas of the metal blanks is accomplished using elevated temperature gas diffusion bonding techniques. The invention contemplates a first thermal cycle during which the pack is diffusion bonded in an evacuated retort at one temperature within a predetermined range of temperatures, and a second thermal cycle during which subsequent superplastic forming of the pack of bonded blanks, with the retort removed, is carried out. Optionally, during the first thermal cycle, a step of superplastic preforming may be carried out whereby the pack is preformed against arcuate or other shaped forming members.

Abstract: Coupling between a control surface and a flexible wing, or other lifting member, is provided by a novel piston-cylinder hinge mechanism which allows the control surface to move, out-of-plane, while following deflections of its associated lifting surface, reducing required actuator energy and enabling more effective use of control forces.

Abstract: A clamp assembly for efficient mounting of wire bundles, hydraulic tubing and other extended service conduits is comprised of a unitary support plate having a triad of support clamp elements formed of strong, resilient metal or plastic with appropriately sized securable openings and means for attaching it to structure in confined or space critical areas or volumes.

Abstract: A hatch opener mechanism mounted flush with a skin panel having a rotatable disk with subjacent spindles and actuator rods, activated by rotating the disk with tool insertable into a socket with a spring biased cover at the center of the disk.

Abstract: A reciprocating rotary tool driver is driven by a motive source which provides power to its tool through a splined shaft while the rotating tool is oscillated in a vertical mode by means of spur gear, worm gear, and crank means.

Abstract: Steel reinforcing elements having layers of chemical conversion iron oxide coatings on the exterior surface thereof such as black iron oxide employed in admixture with castable cement products improve creep resistance and exhibit improved mechanical properties.

Abstract: A method for fabricating a ceramic prosthesis of high aluminum oxide suite for the tibial plateau of a knee joint with the superior (upper) portion of the prosthesis being of a high density Al.sub.2 O.sub.3 having a very low porosity and the inferior (lower) portion being of high density Al.sub.2 O.sub.3 having a high degree of porosity capable of accepting bone growth. The method of fabricating the prosthesis comprises mixing a powdered batch of high aluminum oxide material to produce a viscous slip, adding a foaming agent to the slip, adding a catalyst to the slip to decompose the foaming agent, infiltrating the slip into a sponge, drying the composite, producing a planar surface on the porous layer, fabricating a second denser layer, placing a slurry between the two layers, drying and sintering the laminate.