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Processing and Damage Tolerance of Continuous Carbon Fiber Composites Containing Puncture-Self-Healing Thermoplastic Matrix

Langley Research Center, Hampton, Virginia The initiation and propagation of damage ultimately results in failure of aircraft structural components. Often, impact damage is difficult to identify in-service, and hence design of continuous carbon fiber reinforced polymer (CFRP) composite structure involves up to a 50% knockdown in the undamaged failure strength allowable. If damage is identified in a composite structure, the vehicle must be grounded for structural repair. This involves the grinding away of damaged regions and drilled holes to secure patches. By providing a polymer matrix with the ability to self-heal after impact damage is incurred, vehicle safety is greatly improved by increasing the design allowable for strength, resulting in more efficient CFRP structure.

Posted in: Briefs

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Advanced Supported Liquid Membranes for CO‚2 Control in EVA Applications

This sorbent can be used in the capture of CO2 from coal-fired power plants and other power generation facilities. Lyndon B. Johnson Space Center, Houston, Texas NASA has a clear need to develop new technology in support of its future goals, including missions beyond low-Earth orbit, the possible development of lunar outposts, and the eventual exploration of Mars. As these missions develop, it is anticipated that crewmembers will spend extended time outside the spacecraft and established habitats, requiring new, robust, lightweight life support systems for extravehicular activities (EVAs). One area that is critical to life support systems is the control of CO2, and new spacesuits must be able to accommodate longer EVAs without increasing the size or weight of the current portable life support system (PLSS).

Posted in: Briefs

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Low-Density Titanium-Based Bulk Metallic Glasses with High Glass-Forming Ability

These materials can be used in gears, bearings, latches, inserts, and sheet metal. NASA’s Jet Propulsion Laboratory, Pasadena, California Ti-based bulk metallic glasses (BMGs) and matrix composites (BMGMCs) are a subset of the class of materials known synonymously as amorphous metals, liquid metals, and glassy metals, described by their majority element (in atomic percent) being that of titanium. BMGs are non-crystalline metal alloys based in a wide variety of elemental systems, including zirconium, iron, nickel, hafnium, gold, platinum, palladium, and silver, among others. The vast majority of commercially utilized BMGs are based in Zr-Ti-Cu-Ni-Be or Zr-Cu-Ni-Al due to their relatively low-cost elements and large glass-forming ability (GFA), typically greater than 1 cm. BMGs have long been considered to be a material without a clear application, as the density of BMGs fits squarely between two common, highperformance crystalline alloys that BMGs are usually thought to be replacements for: steel (density = 7.8 g/cm3) and titanium (density = 4.5 g/cm3). For example, Zr-based BMGs generally fit into the range of 6 to 6.5 g/cm3, which makes them difficult to use as direct replacements for conventional materials.

Posted in: Briefs

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Thermal Management Coating (TMC)

The coating uses micro-encapsulated phase-change material. Marshall Space Flight Center, Alabama An experimental study was conducted in conjunction with the research and development program at the NASA Marshall Space Flight Center (MSFC) on thermal protection systems (TPS) for aerospace applications, a new concept for reusable TPS material. The new system uses a micro-encapsulated phase-change material rather than an ablative material to dissipate the heat produced during supersonic flight. This new material absorbs energy as it goes through a phase change during the heating portion of the flight profile and then the energy is released as the material cools. This new TPS consists of micro-encapsulated phasechange material and a resin system to adhere the coating to the structure. The technology has been successfully tested in the hot gas tunnel (aero-thermal heating). The figure shows the test results.

Posted in: Briefs

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AeroHeating Tools (AHT) Suite

Lyndon B. Johnson Space Center, Houston, Texas This suite of computer programs, called “tools,” is used to calculate local flow angles over damage sites in the Shuttle Orbiter Thermal Protection System (TPS). It provides a quick and easy way to compute cross flow angles over points of interest on the Shuttle Orbiter TPS.

Posted in: Briefs

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EXOS Software

Lyndon B. Johnson Space Center, Houston, Texas An improved version of EXOS software allows for the modeling of fabrics, mixtures, and porous materials, and also provides the ability to accept hex mesh geometries. The code employs a novel numerical method, a hybrid particle finite element approach, as well as particles and elements in tandem, each modeling distinct aspects of the physics. Ellipsoidal particles are used to model contact-impact and volumetric thermomechanical response (Euler parameters provide a singularity-free description of particle rotations). Elements are used to model “strength” effects; namely, tensile inter-particle forces and elastic-plastic deviatoric deformation.

Posted in: Briefs, TSP, Electronics & Computers, Coatings & Adhesives

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Scientists Print in 4D

Scientists at the Wyss Institute for Biologically Inspired Engineering at Harvard University and the Harvard John A. Paulson School of Engineering and Applied Sciences have brought a fourth dimension to their microscale 3D printing technology.

Posted in: News

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