Abstract: A method applies one or more films of polynuclear aluminum oxide hydroxide and polynuclear chromium hydroxide to a metal substrate. A method thermally treats the metal substrate with the one or more films at a temperature of at least 250° C., the thermal treatment reducing the polynuclear aluminum oxide hydroxides and the polynuclear chromium hydroxides to at least one layer of aluminum-chromium oxide.

Abstract: In accordance with at least one aspect of this disclosure, a composite structure can be formed of or including a plurality of composite strips. The plurality of composite strips include one or more filler strips which can have at least one filler edge having a filler edge geometry between a first surface and second surface, the second surface being opposite the first surface. The filler edge geometry can be configured to prevent formation of one or more gaps between one or more adjacent composite strips.

Abstract: A drive shaft has a tubular portion extending between axial ends and is hollow. There are deformations on the tubular portions. The deformations extend for a circumferential extent that is less than 180° about a central axis of the tubular portion.

Abstract: A drive shaft for transferring torque including a tubular insert extending along an axis and defining a first layer of the drive shaft including at least one straight portion and at least one undulation, wherein the tubular insert includes a first material having a first deformation temperature, and a polymeric tubular covering defining a second layer of the drive shaft surrounding the tubular insert including a second material having a deformation temperature lower than the deformation temperature of the first material, wherein the covering includes at least one straight portion adjacent to the straight portion of the tubular insert and at least one undulation adjacent to the at least one undulation of the tubular insert.

Abstract: A gas turbine engine component includes a metal substrate and a coating system disposed on the metal substrate. The coating system includes at least one layer of aluminum-chromium oxide.

Abstract: A drive shaft for an aircraft according to an example of the present disclosure includes, among other things, an elongated core extending between a pair of opposed couplings, an energy absorption layer made of a composite comprising metal, the energy absorption layer disposed on the core, and a first composite ballistic layer disposed along a length of the core.

Abstract: In accordance with at least one aspect of this disclosure, a composite structure can be formed of or including a plurality of composite strips. The plurality of composite strips include one or more filler strips which can have at least one filler edge having a filler edge geometry between a first surface and second surface, the second surface being opposite the first surface. The filler edge geometry can be configured to prevent formation of one or more gaps between one or more adjacent composite strips.

Abstract: A sealing process includes applying a first reactant to a substrate having a porous structure, the first reactant comprising a chromium (III) precursor and a transition metal precursor and applying a second reactant to the first reactant, the second reactant comprising a rare earth element precursor and an alkaline earth element precursor to form reservoirs of trivalent chromium in pore space of the porous structure, and a physical barrier over the substrate and the reservoirs.

Abstract: A method for preparing an abradable panel for a rub strip of a fan case of a gas turbine engine includes forming an abradable material into a plurality of panels each comprising an abradable structure; curing the abradable material in the plurality of panels; and installing the plurality of panels into the fan case. The panels can be cured and assembled into a fully assembled rubstrip, and then the assembled rubstrip can be installed into the fan case.

Abstract: A method is disclosed for treating an anodized metal surface. According to the method, polynuclear clusters comprising aluminum oxide hydroxide are applied to the anodized metal surface.

Abstract: An abradable material for a rub strip of a gas turbine engine component includes a polymer matrix, and an organic or inorganic filler distributed through the matrix, wherein the abradable material has a compression spring rate profile including: less than 50,000 lb/in at ?65° F., less than 35,000 lb/in at room temperature, and less than 35,000 lb/in at 200° F.

Abstract: A composite/metal joint includes a composite member, a metallic member, a cylindrical liner, and a fastener. The composite member has a first aperture. The metallic member is disposed adjacent to the composite member and has a second aperture coaxially aligned with the first aperture. The cylindrical liner extends longitudinally from a first end to a second end. The cylindrical liner has a cylindrical outer liner surface and a longitudinally extending third aperture coaxial with the first and second apertures and defined by an inner liner surface. The cylindrical liner is disposed in the first and second apertures with the outer liner surface adjacent to aperture walls of the first and second apertures. The cylindrical liner has a plurality of grooves intersecting the outer liner surface. The fastener is disposed through the third aperture of the cylindrical liner and is configured to attach the metallic member to the composite member.

Abstract: A polymer-matrix fiber-reinforced composite structure includes a plurality of polymer composite layers having at least one polymer composite layer that includes a first polymer-matrix and a first fluorescent agent interspersed through the first polymer-matrix. Damage to the polymer composite structure results in a change in fluorescence at the point of damage. A method for detecting damage in the polymer composite structure described above including the steps of applying light having a wavelength selected to induce fluorescence in the first fluorescent agent to the polymer composite structure, detecting a detected fluorescence pattern, and comparing the detected fluorescence pattern to a predetermined normal fluorescence pattern.

Abstract: A drive shaft for transferring torque including a tubular insert extending along an axis and defining a first layer of the drive shaft including at least one straight portion and at least one undulation, wherein the tubular insert includes a first material having a first deformation temperature, and a polymeric tubular covering defining a second layer of the drive shaft surrounding the tubular insert including a second material having a deformation temperature lower than the deformation temperature of the first material, wherein the covering includes at least one straight portion adjacent to the straight portion of the tubular insert and at least one undulation adjacent to the at least one undulation of the tubular insert.

Abstract: A method of applying a trivalent chromium or chromium-free conversion coating to a metallic substrate including mixing a dye compound that interacts with electromagnetic radiation outside the human visual spectrum but not electromagnetic radiation that is within the human visual spectrum to produce an observable emission into the trivalent chromium or chromium-free conversion coating mixture to allow for inspection of the coating after applied with a correlating electromagnetic radiation source.

Abstract: A composite shaft includes a shaft body formed from a plurality of polymer impregnated fiber-reinforced material layers having an annular outer surface and an annular inner surface defining a passage. A plurality of internal support members extend along the passage. Each of the plurality of internal support members includes a support body formed from molded plastic having an outer surface that abuts the annular inner surface of the support body, a first end, an opposing second end, and a circular end wall arranged at one of the first end and the opposing second end.

Abstract: A method of making cerium citrate includes combining cerium carbonate and citric acid to produce cerium citrate and carbon dioxide. The cerium citrate is substantially free of negative ions other than citrate. The cerium citrate can be used in a corrosion inhibitor composition.

Abstract: The present disclosure provides assemblies, systems and methods of quality control and service inspection for metallic electro-mechanical components. More particularly, the present disclosure provides assemblies, systems and methods of quality control and service inspection for metallic electro-mechanical components (e.g., stator components) utilizing fluorescent agents. The present disclosure provides both (i) surface/assembly designs, and (ii) methods of their inspection. In the present disclosure, fluorescent agents can be mixed with protective and/or added layers to serve as bright contrast media under a light source (e.g., ultraviolet (“UV”) light source). It is noted that in a case of imperfect coating or service corrosion, gaps in reflection can serve as clear indications of either inadequate quality or excessive corrosion-driven degradation of the components.

Abstract: A mechanical part configured to be placed under torque. The mechanical part includes an inner tube having, a corrugated web, and an outer shell. The inner tube has an outer tube circumference, a tube axial direction, and a tube length. The corrugated web has a plurality of peaks and a plurality of troughs, a height measured as a difference between one of the peaks and one of the troughs, and a web length perpendicular to the height and in the tube axial direction. The outer shell has an inner shell circumference, an outer shell circumference, and a shell length. The plurality of troughs is affixed to the outer circumference of the inner tube. The plurality of peaks is affixed to the inner shell circumference of the outer shell. The web length is aligned with the tube length and the shell length.

Abstract: In accordance with at least one aspect of this disclosure, a composite structure can be formed of or including a plurality of composite strips. The plurality of composite strips include one or more filler strips which can have at least one filler edge having a filler edge geometry between a first surface and second surface, the second surface being opposite the first surface. The filler edge geometry can be configured to prevent formation of one or more gaps between one or more adjacent composite strips.