Abstract: A die for superplastically forming a blank of superplastic material to make a part includes a die base enclosing a cavity having a topography shaped like the part, and a die lid shaped and sized to fit over the die base and engage a peripheral surface of the die base around the cavity. The die lid has an underside communicating with the die cavity and a recess opening in the underside positioned in the die lid to overlie an area on the die cavity at which the blank othewise would experience insufficient thinning during superplastic forming of the blank. Gas vents are provided in the base and the lid for first delivering forming gas under pressure into the cavity to preform the blank into the lid recess to prethin the blank in the thick areas, and thereafter vent the cavity gas pressure and deliver forming gas under pressure to the lid to form the blank into the cavity in the die base.

Abstract: A process for consolidating a composite material comprises the steps of forming a workpiece including a matrix interspersed with fibers, supporting the workpiece by an electrically conductive support, inductively heating the support and thereby conductively heating the workpiece, and applying pressure to the heated workpiece. We apply the pressure by passing the support and workpiece through spaced rolls. To keep the workpiece from sticking to the support (i.e., the mandrel), we use boron nitride as a release agent.

Abstract: A ceramic composite is provided comprising ceramic fibers and microparticles bound together as a porous matrix with a ceramic binder. The ceramic composite is particularly useful for transporting cryogenic fluids.

Abstract: For forming or consolidating organic matrix composites, for example, an organic matrix composite panel is sealed in a "retort" 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: The physical properties of high performance composites can be tailored by using blends to make the composites. The resulting composites are relatively easy to make and have long-term, high performance capabilities even in harsh service conditions. The blends of the present invention include at least one oligomer having an aromatic, aliphatic, or mixed aromatic and aliphatic backbone from one chemical family and an unsaturated hydrocarbon end cap and at least one polymer from a different chemical family. Upon curing, the oligomer in the blend addition polymerize to form composites possessing advanced properties with respect to those exhibited by the pure oligomer or the pure polymer. Coreactive oligomer blends can be used instead of a pure oligomer to form composites that include addition polymers, block copolymers, and the compatible polymer, thereby further achieving a tailoring of properties in the cured composite. The blends can be prepregged and cured to form composites.

Abstract: A ceramic composite is provided comprising ceramic fibers and microparticles bound together as a porous matrix with a ceramic binder. The ceramic composite is particularly useful for transporting cryogenic fluids.

Abstract: Quality thermoplastic fusion welds are formed in prefabricated resin composite parts by aligning a susceptor along a bondline between parts with the induction coil segments of a solenoid induction coil along the centerline of the coil. Energizing the coil heats the susceptor to form the weld at the bondline. For this operation, our induction heating workcell users complementary dies that define a central cavity with an oval pattern of induction cool segments surrounding all faces of the cavity where the preform composite parts and susceptor are positioned.

Abstract: A method of producing a ceramic die for use in superplastic forming includes designing a free standing generally block-shaped ceramic monolithic die base with a bottom surface on which the die rests, and a top surface, opposite to the bottom surface, in which a forming cavity is located and which is surrounded by a contact surface. The forming cavity is shaped like the desired shape of sheet metal parts to be formed by superplastic forming in the die. A die lid is designed having a horizontal cross sectional shape and size approximately equal to the die base, and having a contact surface corresponding in size and contour to the die base contact surface, so that the lid may be placed on the base with the contact surfaces aligning and in contact.

Abstract: A method for fabricating composite parts having improved pull-off strengths between portions of the composite part. In one embodiment, a sine wave spar is formed from two U-shaped channels having opposing flanges and a central web. The U-shaped channels are joined along the webs. The triangular gap created between the edges of the two U-shaped channels along the joining surface are filled by interleaving layers of unidirectional prepreg with the layers of prepreg that form the caps or flanges of the sine wave spar. In one embodiment of the invention, the layers of prepreg used as radius filler plies become progressively narrower as they are interleaved from within the gap outward towards the outer edge of the flanges. In another embodiment, the layers of prepreg used as radius filler plies become progressively narrower as they are interleaved between the cap plies.

Abstract: A fighter aircraft achieves low aerodynamic drag and radar signature without sacrificing flight performance through a unique arrangement of the air inlets, the weapons bays, and the main landing gear. Separate main and auxiliary weapons bays permit a narrower fuselage than could be obtained with a single common bay. Also, the auxiliary weapons bays and the landing gear can be aligned outboard of the main weapons bay without needing to increase the length or width of the aircraft. The air intake ducts extend aft from each intake and curve upwardly and inwardly over the main weapons bay. The result of the design configuration is an aircraft of minimum fuselage width for optimal performance and which has a forward aspect reduced to the minimum necessary to accommodate the components that need forward visibilities, which translates to minimum aerodynamic drag and radar signature.

Abstract: A clutch for an interior latch handle of a plug-type airplane door is described which decouples the handle from the latch-operating linkage so the handle will not be backdriven into the passenger space when the exterior latch handle is operated to open the door from outside the airplane. The clutch includes a probe mounted on the base of a handle mechanism assembly in line with the handle, and a pawl pivotally mounted in the handle and disposed to engage a lug splined to the handle shaft and torsionally coupled to the latch. When the handle is in its "home" or "closed" position, the probe engages a roller on the end of an arm connected to the pawl and rotates the pawl away from the lug so that the handle shaft will not backdrive the handle into the passenger space when the exterior latch handle is operated to unlatch the door. When the handle is moved away from the probe, the pawl engages the lug to establish two-way torsional coupling between the handle and the latch.

Abstract: The present invention is a directional reflectometer that measures the optical bidirectional reflectance distribution function [BRDF] of a surface in situ on a finished article, e.g. a vehicle, to provide information on its surface emissivity. The light wavelength may be IR, near-IR or visible. Light, preferably focused to a small spot on the surface, is projected onto the surface at an angle adjustable in azimuth and elevation. A wide angle mirror and/or lens system transfers light scattered from the surface onto an imaging sensor, preserving scattering angle information and thereby permitting the BRDFs for a given incidence angle and all scattering angles to be measured simultaneously. A hand held or laptop computer sets the incidence angle, reads the sensor outputs and renders judgments on the quality of the surface in a factory or field environment.

Abstract: A data bus for a fault tolerant avionics digital autonomous terminal access communications system is provided with a terminating resistor for absorbing or sufficiently attenuating signals incident on it so that they are not reflected back into the transmission line at amplitudes where they would cause distortion of the data signal. The data bus and terminating resistors are designed to continue providing full operational capability even if the electrical resistance of the terminating resistor increases by about 5%. The terminating resistor has at least about twenty resistive elements connected in parallel across two conductors in the data bus at one end thereof. Each resistive element includes a non-conductive substrate having a face surface on which is deposited a conductive film to produce a primary resistor.

Abstract: A cold surface is obtained by coating a mat of ceramic particles that are bound together with a sol-gel binder and cooling the surface with a cryogen that wicks to the surface through pores in the mat.

Abstract: A conformal skate for use in an inductive welding system for creating a fusion bond along a bond line between two thermoplastic parts includes a wheel having a circumferential casing made of fluid impervious flexible material. The wheel is rotatably mounted on a fixed axle by fluid tight bearings. The axle has an axial passage for admission of pressurizing and cooling fluid, and for power leads for the coil and for leads for sensors inside the wheel. A vertical mount on the axle supports the coil for vertical motion and biases the coil downwardly so that it remains in contact with the inside surface of the casing despite unevenness or contour changes in the upper surface of the top part or changes in the wheel shape when the fluid pressure in the wheel or downward force on the axel is changed.

Abstract: A method and apparatus for accurately positioning parts precisely in a predetermined location, including a frame having a part receiving zone on which said parts are placed for movement to the predetermined location. Two positioners are mounted on linear bearings connected to the frame and are connected to a cable for opposed motion toward and away from the part on the receiving zone under control of the cable. The cable is trained around a four pulleys mounted on said frame and connected to a cable cylinder. The cable passes axially through cylinder and connects to a piston on the centerline of the piston. Movement of the piston in one direction in the cylinder is operative to move the cable and the attached positioners toward each other to center the part. Movement of the piston in the opposite direction moves the positioners away from each other to release the part.

Abstract: A ceramic composite is provided comprising ceramic fibers and microparticles bound together as a porous matrix with a ceramic binder. The ceramic composite is particularly useful for transporting cryogenic fluids.

Abstract: A conformal mask permits the manufacture of precision frequency selective surfaces (FSS) that have patterns on complexly curved surfaces. These FSSs are used in precision radomes. The mask has a transparent substrate and a patterned opaque layer on the substrate. The layer may be patterned by laser ablation. Alternatively, the patterning of the opaque layer can be accomplished by applying a layer of photosensitive material over the opaque layer and then defining temporary and permanent areas thereof. The temporary areas of the photosensitive layer and the opaque layer are removed sequentially to define the transparent portions of the mask. Parts are made by intimately mating the mask and a part body to which a layer of metal and a layer of photosensitive material have been applied, and exposing the part to radiation through the mask.

Abstract: A process for making an integrated terminating resistor on a two-conductor data bus includes making a series of individual resistor elements and assembling the resistor elements in a stack of parallel, spaced array of elements. The elements are soldered together between end portions of the two conductors of the data bus at both ends thereof by inserting the conductors into two diametrically opposed, axially aligned notches in all of the resistor elements and heating solder in the notches to reflow the solder to bond the conductor in the notches. A parallel electrical and mechanicalconnection is thereby established, connecting the elements together electrically and mechanically in a closely spaced array. The array is sealed in a shock absorbing and abrasion resistant enclosure.

Abstract: A latch for retaining printed circuit boards (PCB) or other types of daughter cards (29) in a card file (11) is disclosed. Two latch mechanisms (43a and 43b), one located adjacent the outer corner of each card, engage latch slots (35) when the cards (29) are correctly installed. Each latch mechanism (43a and 43b) includes a latch housing (45), a plunger assembly (47) mounted in the latch housing (45), and large coil springs (49a and 49b) that create a force in a direction parallel to the direction of card installation. The large coil springs (49a and 49b) urge the plunger assembly (47) away from the direction of card installation and out of alignment with an opening (77) in the latch housing (45). The plunger assembly (47) includes a plunger housing (53), a latch pin (55), a smaller coil spring (59), and a latch pin retraction lever (57).