Abstract: The strength of composite patches is improved over conventional bolted or bonded patches by including Z-pins in the patch/parent structure interface to provide a mechanical link with small stress concentration between the patch and the parent structure. In some cases, we achieve a stronger repair removing the pins to leave holes that fill with resin from the patch during the curing or bonding operation.

Abstract: Prefabricated composite detail parts use precured strips that include Z-pin reinforcement along the bond line. Each strip has Z-pin stubble protruding from opposed faces so that the pins are embedded into the detail parts when the joint forms.

Abstract: Prefabricated composite detail parts use precured strips that include Z-pin reinforcement along the bond line. Each strip has Z-pin stubble protruding from opposed faces so that the pins are embedded into the detail parts when the joint forms.

Abstract: Improved pin-reinforced sandwich structure ties the face sheets (typically on opposite sides of a foam core) together with a plurality of Z-pins that extend into each face sheet (through the core). The pins are arranged in a tetrahedral or hat section configuration in 2-dimensional or 3-dimensional arrangements to provide enhanced reinforcement, particularly in shear. We are able to improve the pulloff strength additionally by dimpling the core surrounding the pins to produce adhesive fillets along the pins.

Abstract: Thin film metal particulates are removed from FEP sheetstock cheaply and quickly by immersing the coated FEP first in a base and then in an acid. Occasionally, ultrasonic vibration of the FEP may also be required. The particulates are useful as paint pigments when isolated and conversion coated. The FEP is reusable.

Abstract: A surface treatment, especially for titanium and aluminum alloys, forms a sol-gel film covalently bonded on the metal surface to produce strong, durable adhesive bonds between the metal and an organic adhesive without using toxic chemicals and while significantly reducing or eliminating rinse water requirements of traditional anodizing or etching processes. An aqueous sol containing an alkoxyzirconium and an organosilane with an organic acid catalyst and zirconium stabilizer is applied to etched or grit blasted substrates by dipping, spraying, or drenching, to produce bonds in a single application comparable in strength and performance to standard anodize controls. Parameters affecting performance include the sol composition, the Si/Zr ratio, the ratio of sol ingredients, the concentration of the sol, the carrier solvent, solution age, catalysts, surface pretreatment, application method, curing process, and primer used.

Abstract: A surface treatment, especially for titanium and aluminum alloys, forms a sol-gel film covalently bonded on the metal surface to produce strong, durable adhesive bonds between the metal and an organic adhesive without using toxic chemicals and while significantly reducing or eliminating rinse water requirements of traditional anodizing or etching processes. An aqueous sol containing an zirconium and an organosilane with an organic acid catalyst and alkoxyzirconium stabilizer is applied to etched or grit blasted substrates by dipping, spraying, or drenching, to produce bonds in a single application comparable in strength and performance to standard anodize controls. Parameters affecting performance include the sol composition, the Si/Zr ratio, the ratio of sol ingredients, the concentration of the sol, the carrier solvent, solution age, catalysts, surface pretreatment, application method, curing process, and primer used.

Abstract: The strength of composite patches is improved over conventional bolted or bonded patches by including Z-pins in the patch/parent structure interface to provide a mechanical link with small stress concentration between the patch and the parent structure. In some cases, we achieve a stronger repair removing the pins to leave holes that fill with resin from the patch during the curing or bonding operation.

Abstract: The present invention is a method for improving the strength and quality of thermoplastic welds by annealing the weld following its formation at a temperature of at least about 500.degree. F. (i.e., about 125.degree. F. below the melt) for about 20 minutes to control cooling of the weld.

Abstract: A double shear lap joint is formed between metal and composite structure by welding Z-pins in the composite in the joint area to the metal tangs on the metal structure. The joint has modest strength but is less susceptible to shock damage than an adhesive bond or to notch effect crack propagation damage associated with fastened metal/composite joints.

Abstract: A slurry is molded from ceramic fibers and/or microparticles to form a soft felt mat which is impregnated with a sol prior to drying the mat. A catalyst for the sol is caused to diffuse into the mat by exposing the mat to the catalyst and subjecting the mat to a soak time during which the catalyst diffuses into the mat and causes the sol to gel. The sol-gel binder forms bonds so that the mat is dimensionally stabilized. The mat is dried to produce ceramic insulation.Ceramic insulation having a consistent microstructure and a fully gelled sol-gel binder through its entire thickness is also provided.

Abstract: I improve the impact shock resistance of bonds between composite elements by including Z-pin reinforcement. I prepare stubbled composite structure by using peel plys over the appropriate surface of the composite during pin insertion using conventional processes. I then use the stubbled composite structure with padups, as necessary, to produce the Z-pin reinforced joint or bond between composite elements using any of adhesive bonding, cocuring, or thermoplastic welding.

Abstract: A surface treatment, especially for titanium and aluminum alloys, forms a sol-gel film covalently bonded on the metal surface to produce strong, durable adhesive bonds between the metal and an organic adhesive without using toxic chemicals and while significantly reducing or eliminating rinse water requirements of traditional anodizing or etching processes. An aqueous sol containing an alkoxyzirconium and an organosilane with an organic acid catalyst and zirconium stabilizer is applied to etched or grit blasted substrates by dipping, spraying, or drenching, to produce bonds in a single application comparable in strength and performance to standard anodize controls. Parameters affecting performance include the sol composition, the Si/:Zr ratio, the ratio of sol ingredients, the concentration of the sol, the carrier solvent, solution age, catalysts, surface pretreatment, application method, curing process, and primer used.

Abstract: A fibrous ceramic mat is molded from a slurry of ceramic fibers and/or ceramic microparticles and/or a metal. The mat is impregnated with a sol prior to drying. A catalyst for the sol is introduced into the mat to cause the sol to gel. The sol-gel binder forms bonds so that the mat is dimensionally stabilized. The mat is dried to produce the desired ceramic insulation that has preferably a consistent microstructure and a fully gelled sol-gel binder through its entire thickness. When a metal is used, it corrodes (i.e., oxidizes) or otherwise reacts to form a refractory binder that augments the sol and reduces the need to infuse sol incrementally to achieve strength. Using metal powder significantly reduces the cost of manufacture.

Abstract: A magnetic field sensor which can be used as an active antenna is disclosed that is capable of small size, ultrawideband operation, and high efficiency. The sensor includes a multiplicity of magnetic field transducers, e.g., superconducting quantum interference devices (SQUIDs) or Mach-Zehnder modulators, that are electrically coupled in a serial array. Dummy SQUIDs may be used about the perimeter of the SQUID array, and electrically coupled to the active SQUIDs for eliminating edge effects that otherwise would occur because of the currents that flow within the SQUIDs. Either a magnetic flux transformer which collects the magnetic flux and distributes the flux to the transducers or a feedback assembly (bias circuit) or both may be used for increasing the sensitivity and linear dynamic range of the antenna.

Abstract: I achieve positive, accurate placement of Z-pins in resin composite parts using a tool to guide the pins from the foam preform into the part. The tool has a reciprocating piston for crushing the foam to insert the pins and uses a positive stop to control penetration depth and positioning of the Z-pins. The tool also includes a plurality of bores for guiding the individual pins from the foam preform to the part while separating the part from the foam preform.

Abstract: An apparatus for thermoplastic welding together by fusion bonding an assembly of composite parts, each having a resin-rich thermoplastic surface layer, along bond lines containing a conductive susceptor includes a weld skate that can be moved along guiding and supporting tooling over the bond line to effect the weld. The skate has an induction work coil and two pressure pads, one on each side of the coil in its direction of motion in operation, for applying pressure to the parts while said induction work coil induces eddy currents in the susceptor to heat the susceptor by resistive heating and melt the thermoplastic surface layers. The skate has bearings projecting from its side into cam grooves machined into the sides of the tooling for guiding and supporting the skate during welding by the induction work coil.

Abstract: A hybrid metal webbed composite beam includes a metal I or T web section and a composite cap formed over and adhered to the I or T web. The beam incorporates the advantages of metals and composites in modern aerospace construction allowing thermoplastic welding of the beam to skins while having the strength of metal.

Abstract: A supersonic aircraft engine, either turbojet or turbofan, having a compressor, a diffuser, a combustion chamber, a turbine, and a nozzle passageway, and a turbine bypass passageway for bypassing compressor exit flow around the turbine. The bypass passageway comprises a plurality of supply pipes, and a flow control valve is mounted in each of the plurality of supply pipes. Under given flight conditions, a predetermined number of these flow control valves are fully closed, while the remaining flow control valves are opened as necessary for the given flight condition to obtain a desired rate of turbine bypass flow. The turbine bypass flow is supersonically mixed with the turbine exit flow during transonic acceleration or discharged externally of the engine housing. The turbine bypass flow is primarily composed of boundary layer air flowing along the inner and outer walls of the diffuser.

Abstract: A process for superplastically forming a part from a blank of superplastic material such as titanium alloy, including enclosing and capturing a sheet of superplastic material having uniform thickness between a die lid and a die base. The die lid has a deep recess where localized prethinning of the blank would minimize excessive thinning of the formed part elsewhere on its topography. The peripheral edges of the blank is clamped between the lid and the base by exerting a squeezing force, typically be a press, and the die is heated, along with the blank, to the superplastic temperature of the blank. The die base is pressurized to preform portions of the blank opposite the lid recess into the recess to form a prethinned bulge. After preforming, the die lid above the blank is pressurized to reverse the prethinned bulge down into the cavity and to form the blank into the cavity.