Mechanical & Fluid Systems

Wallops Flight Facility 6U Advanced CubeSat Ejector (ACE)

Goddard Space Flight Center, Greenbelt, Maryland Six-unit (6U) CubeSats are recognized as the next nanosatellite to be considered for standardization. The CubeSat standard established by California Polytechnic University (Cal Poly), which applies to 1U–3U sizes, has proven to be a valuable asset to the community. It has both provided design guidelines to CubeSat developers and a consistent, low-risk interface to launch service providers. This has ultimately led to more flight opportunities for CubeSats. A similar path is desired for the 6U CubeSat. Through this process of standardization, a consistent, low-risk interface for the 6U needs to be established.

Posted in: Briefs, TSP

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Improved Attachment Design for Ceramic Turbine Blades Via Hybrid Concepts

This approach facilitates increased precision and ease of handling the blades during assembly. John H. Glenn Research Center, Cleveland, Ohio This innovation is a hybrid metal-ceramic matrix composite (CMC) turbine blade in which a SiC/SiC CMC airfoil section is bonded to a single-crystal superalloy root section in order to mitigate risks associated with an all-CMC blade inserted in a superalloy disk. This will allow current blade attachment technology (SX blade with a dovetail attachment to a slotted Ni disk) to be used with a ceramic airfoil. The bond between the CMC and single crystal will be primarily mechanical in nature, and enhance with clamping arising from thermal expansion mismatch. Two single-crystal root sections will be bonded to each other using diffusion bonding at temperatures near 1,200 °C. The single crystals will form a clamshell around the CMC, with little or no gap between the metal and ceramic. Upon cooling, the metal will shrink around the CMC to firmly clamp it. It is envisioned that this will allow the blade root to operate at temperatures up to about 800 °C. Single crystals will resist stress relaxation at this temperature, thus maintaining clamping loads for long lives. The hybrid concept plus the method of manufacture is new technology.

Posted in: Briefs, TSP

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Powdered Copper Cryogenic Heat Exchanger

This technology provides a high level of thermal performance while dramatically simplifying the chore of determining safety factors. John F. Kennedy Space Center, Florida This work involved designing a liquid nitrogen cold-plate heat exchanger with a high thermal mass using code-standard, high-pressure tubing. High thermal mass requires a substantial amount of material, so heat exchangers of this type are usually fabricated from a solid piece of metal (such as copper) with fluid paths machined into the component. However, standard tubing was desired for the fluid path due to its pressure rating and predictability. The key problem was how to embed copper tubing into a larger mass while maintaining good heat transfer properties.

Posted in: Briefs, TSP

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Friction Reduction: Finding New Gains in Powertrain Efficiency

In conjunction with SAE International Facing the super-stringent U.S. and European CO2 emission requirements for 2020 and beyond, powertrain engineers need to squeeze every last tenth of a mile-per-gallon of efficiency out of new engines, transmissions, and drivelines. Reducing internal friction on rotating and reciprocating components, as well as across systems, is now a major design and engineering priority. New technology solutions in the critical areas of powertrain systems design, bearings, and seals are appearing as a result. This webcast’s panel of experts will examine these issues and offer solutions. Webcast attendees will be invited to interact with the experts during the Q&A portion of the 60-minute webcast.

Posted in: On-Demand Webinars

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The Ultimate Shaft-To-Hub Connection

Polygon Shapes - Multi-Faceted Problem Solvers Kinematically ground polygonal shapes have been used as drive connections for more than 45 years. What is now referred to as Polygon Systems was developed by Fortunawerke, Stuttgart, West Germany, who patented a grinding machine capable of producing matched polygonal shaft and bore diameters.

Posted in: Mechanics, White Papers, White Papers

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Heavy Duty Shaft Coupling Strategies

Heavy-duty shaft couplings have traditionally had a couple of defining design characteristics. For one, these couplings usually rely on keyed shaft connections. For another, they tend to be overengineered with regard to stiffness. Keyed connections and excessively rigid coupling designs do have some under-recognized limitations— especially in large industrial, material handling, construction and mining machines.

Posted in: White Papers

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Diminutive Assembly for Nanosatellite deploYables (DANY) Miniature Release Mechanism

New deployment mechanism offers improved reliability with minimum space and weight penalty. Goddard Space Flight Center, Greenbelt, Maryland CubeSat appendices such as solar panels and antennas often need to be constrained by a release mechanism during launch. These appendices are then deployed once the desired orbit is reached. The usual constraint method used is a combination of an unpredictable/ unreliable fishing line and burning wire. If a proper release mechanism is used, it utilizes a considerable amount of CubeSat internal space, making the internal packaging of the satellite more difficult. These two methods have adverse effects on CubeSat performance.

Posted in: Briefs, TSP

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