Browse Topic: Ceramics

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RESEARCH OF THE EFFECTS OF INTEGRATION INTO ARMOR ON THE PERFORMANCE OF SPINTRONIC MICROWAVE DETECTORS2024-01-333411/15/2024
ABSTRACT The authors studied the effects of different types of armor on the performance of spin-torque microwave detectors (STMD). Working prototypes of novel nano-sized spintronic sensors of microwave radiation for battlefield anti-radar and wireless communications applications are being integrated into Sensor Enhanced Armor (SEA) and Multifunctional Armor (MFA) and tested in SEA-NDE Lab at TARDEC. The preliminary theoretical estimations have shown that STMD based on the spin-torque effect in magnetic tunnel junctions (MTJ), when placed in the external electromagnetic field of a microwave frequency, can work as diode detectors with the maximum theoretical sensitivity of 1000 V/W. These STNO detectors could be scaled to sub-micron size, are frequency-selective and tunable, and are tolerant to ionizing radiation. We studied the performance of a STMD in two different dynamical regimes of detector operation: in well-known traditional in-plane regime of STMD operation and in recently discovered novel out-of-plane regime.
Bankowski, Elena, Meitzler, Thomas, Pesys, Tomas
Recommended Practice for Determining Material Properties of Li-Battery Cathode Active MaterialsJ3021_202105 (Current)5/28/2021
This SAE Recommended Practice provides a set of test methods and practices for the characterization of lithium ion battery cathode active material. It is beyond the scope of this document to establish criteria for the test results, as these are usually established between the vendor and customer. It should be noted that materials properties can vary substantially between classes of materials (e.g., LNO and LFP) and caution should be exercised when attempting to directly compare their chemical and physical properties. While these distinctions are important for the manufacturer, this document focuses on the techniques to measure the materials properties and not their absolute or relative values. Future materials such as solid-state batteries and sulfides are beyond the scope of this document. It is beyond the scope of this document to examine the rheological properties of the cathode material dispersed in a coating slurry since such properties are influenced by the conductive additive, binder, and solvent, which are determined by the coating process. It is beyond the scope of this document to examine the electrochemical properties of cathode materials since these are influenced by electrode and ultimately cell design. Due to the difference in electrical and electrochemical properties of the cathode material, it is unrealistic to establish an electrode and cell design that would justly compare different cathode active materials.
Battery Materials Testing Committee
Overlap Shear Test for Automotive Type Sealant for Stationary Glass BondingJ1529_202101 (Current)1/7/2021
This SAE Recommended Practice defines a procedure for the construction and testing of glass to metal lap shears for determining shear strength of sealant adhesives for automotive stationary glass bonding. This procedure can also be used for fiber reinforced plastic (FRP) when used in place of metal.
Materials, Processes and Parts Council
New Coating Process Lights Porous Electronics and SensorsTBMG-373648/1/2020
Researchers have shown how to coat glass and plastic with porous titanium dioxide. The fabrication process is straightforward, the materials are cheap, and the ceramic’s gas sensing performance is considerably improved compared with current devices.
Alternatives to Cadmium PlatingAIR4160B (Current)3/24/2020
To document and provide access to information obtained by an industry survey.
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Celebrating Women in Engineering & Science: Renee Bernstein, CEO, Cotronics CorporationTBMG-361673/1/2020
Thermally Conductive Polymer FilmsTBMG-359772/1/2020
Polymers are commonly used for thermal insulation as they are excellent at trapping heat. Thin polymer films were developed that conduct heat — an ability normally associated with metals. The films, which are thinner than plastic wrap, conduct heat better than many metals including steel and ceramic.
Mechanical and Corrosion Behaviour of Al 7075 Composite Reinforced with TiC and Al 2 O 3 Particles2019-28-009410/11/2019
Various research regarding new types of fabrication and modifications of Aluminium alloy to improve the existing properties are going on. The wide range application of aluminium alloy is in aerospace and Automobile Industries. The demand for this material improved by mechanical properties with little to zero increment in weight. The current work is based on the fabrication of hybrid aluminium metal matrix composites with the addition of TiC (Titanium Carbide) and Al2O3 (Aluminium Oxide) reinforcement particle using stir casting technique. Three types of hybrid composite samples were prepared based on the weight percentage 5% Al2O3+0% TiC (sample-1), 8% Al2O3 + 12% TiC (sample-2), 20% Al2O3+15% TiC (sample-3). The objective of the study is to analyze the mechanical and corrosion properties of the hybrid composite with the influence of the reinforcement and varying the weight fraction of the particles. Overall, It is observed that a gradual increase in the hardness value in sample-1(83 BHN), Sample-2 (88 BHN) and sample-3 (96 BHN). This trend can be explained by the particulate strengthening of TiC over the soft ductile Al7075 during stir casting. The microstructure also provides a convincing explanation of the increased hardness. The tensile test shows that an increasing trend of yield strength in sample-1 to 3, and a decreasing trend of UTS and YS in sample-2 to 3. This is due to the high content of Al2O3. The corrosion behavior is tested by weight loss method using salt spray test. The sample-3 with the highest content of Al2O3 have the least weight loss and highest corrosion resistance than the other samples.
Jaiswal, Subham, Rajamurugan, Govindasamy, Krishnasamy, Prabu, Shaswat, Yashwardhan, Kaushik, Mishra
Ceramic Bound Materials: A Suitable Solution for Light Brakes2019-01-21099/15/2019
A ceramic bound matrix has been investigated to be used as a friction material. The materials were produced by means of ceramic technology using frits containing silicates, and ceramic friction modifiers such as tin oxide, zircon, iron oxide, magnesium oxide. Four formulations were tested by means of a tribometer (pin-on-disc tester) using a gray cast iron counterpart. Test section included speeds between 1 and 12 ms-1, and loads between 25 and 400 N. The coefficient of friction of the tested specimens were between 0.7 and 0.4, and exhibited sensitivity to speed at low loads (25 N), while they are quite stables at high loads (400N). The characterization of the tribolayers was carried out by means of scanning electron microscopy. The four developed materials were named A, B, C, and D. They exhibited different wear rates and coefficients of friction. All the materials exhibited sensitivity to speed, while showed a lower sensitivity to load. The coefficient of friction level seems to be suitable for brake applications, oscillating between 0.6 and 0.4, depending on the test section. This kind of materials with further efforts can be possibly useful in future electric vehicles that will not demand large and expensive brakes.
Dante, Roberto C., Cotilli, Edoardo, Conforti, Michael, Cotilli, Mario, Serrano-Posada, José Carlos, Schramm, Tobias, Ostermeyer, Georg-Peter, Dastrù, Marco
Thermal Conductivities of Some Polymers and Composites19AERP08_098/1/2019
Assessing the performance of polymers used in structural armor and filament winding applications. Army Research Laboratory, Aberdeen Proving Ground, Maryland Thermoset polymers are good electrical insulators that are used in applications ranging from electronics to composite armor. They are rather poor thermal conductors, however. For encapsulation of electronic components and devices, there is a huge amount of literature on filled polymers, particularly epoxies. One source provides a recent review of thermal conductivity (Kt) of filled polymers with emphasis on carbon nanotube loading. As an example of a low Kt polymer, a Kt of 0.3 watts per meter per degree kelvin (W/MK) for unfilled polyurethane from an unidentified source has been cited, with higher values for filled resin. Measurements have also been reported on particle-filled polypropylene with a neat resin Kt of 0.27 W/MK. These thermal conductivities are higher than those of most epoxies, and much lower than those of metals and crystalline ceramics.
Thermal Conductivities of Some Polymers and CompositesTBMG-348688/1/2019
Thermoset polymers are good electrical insulators that are used in applications ranging from electronics to composite armor. They are rather poor thermal conductors, however.
High-Temperature Dielectric NanocompositeTBMG-348998/1/2019
A nanocomposite was developed that could be a superior high-temperature dielectric material for flexible electronics, energy storage, and electric devices. The nanocomposite combines one-dimensional polymer nanofibers and two-dimensional boron nitride nano-sheets. The nanofibers reinforce the self-assembling material while the white graphene nanosheets provide a thermally conductive network that allows it to withstand the heat that breaks down common dielectrics, the polarized insulators in batteries, and other devices that separate positive and negative electrodes.
Wristbands Do Health Check During WorkoutTBMG-345646/1/2019
Next-generation fitness sensors could give deeper insights into human health through noninvasive testing of bodily fluids. A stretchy patch developed at KAUST could help this approach by making it easier to analyze sweat for critical biomarkers.
Reliable Structures and Wearable Systems Call for Multiphysics SimulationTBMG-344425/1/2019
The increasing demand for miniaturized electronics and Internet of Things (IoT) devices has created new challenges for the specialists who design microdevices such as actuators, controllers, drivers, sensors, and transmitters. From responsive equipment and wearable monitors to energy efficient lighting in the office and automation in the factory, engineers need to bridge the microscopic components of semiconductors and our macroscopic world with reliable and innovative products. This shift has inspired engineers to find new solutions by exploring their ideas in the virtual world of numerical simulation.
Metallic Hollow Nanoparticle FabricationTBMG-341564/1/2019
NASA Langley Research Center has developed new methods for fabricating hollow nanoparticles using dendrimer molecules. Dendrimers are used as templates to control the size, stability, and solubility of these metallic nanoparticles ranging in metal lining thicknesses from less than 5 nm to several tens of nm.
Failsafe Linear Magnetic BrakesTBMG-341134/1/2019
Linear permanent magnet brakes, also known as eddy current brakes, are a failsafe, power-free deceleration system that is used in conjunction with a metal reaction plate. Ceramic or rare earth magnets are bonded to a steel back iron plate; no input power is required.
5 Ws of 3D-Printing Piezoelectric MaterialsTBMG-339203/1/2019
Piezoelectric materials are used in everything from cellphones and wearables, to robotics, energy harvesting, and tactile sensors.
Process Developed to 3D Print Piezoelectric MaterialsTBMG-340223/1/2019
The piezoelectric materials that inhabit everything from our cell phones to musical greeting cards may be getting an upgrade thanks to work discussed in the journal Nature Materials. Xiaoyu “Rayne” Zheng, assistant professor of mechanical engineering in the College of Engineering and a member of the Macromolecules Innovation Institute, and his team have developed methods to 3D print piezoelectric materials that can be custom designed to convert movement, impact, and stress from any directions to electrical energy.
Contaminant-Free SteelTBMG-336081/1/2019
For many highly stressed engineering applications like bearings and gears, contaminated steel parts can lead to devastating outcomes such as an emergency shutdown or the end of a mission. Ensuring that these critical components are as homogeneous as possible and free from porosity and other flaws is vital to performance, yet conventional steelmaking processes have multiple pathways of entry for unwanted contamination.
Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate 29Fe - 22Cr - 21Ni - 18.5Co - 3.2Mo - 2.8W - 0.78Ta - 0.30Al - 0.05Zr - 0.05La - 0.20N Solution Heat TreatedAMS5874C (Historical)10/10/2018
This specification covers a corrosion and heat-resistant alloy in the form of sheet, strip, and plate.
AMS F Corrosion Heat Resistant Alloys Committee
High-Kinetic-Energy Penetrator Shielding and High-Wear-Resistance Materials Fabricated with Boron Nitride Nanotubes and BNNT Polymer CompositesTBMG-328319/1/2018
In recent years, anti-penetration materials have been more widely used for armor, bulletproof vests, and micrometeoroid and orbital debris protection layers for space-suits, space vehicles, and structures. Micrometeoroids develop very high kinetic energies as they travel through space, and pose a significant hazard to spacecraft and astronauts. The velocities of micrometeorites can reach 20 kilometers per second prior to impact on the lunar surface. Therefore, a new protective system utilizing new materials is needed to effectively shield the space vehicles and structures against the high-kinetic-energy penetrators as well as provide penetration-resistant spacesuits. In order to maximize the protection ability against high-kinetic-energy penetrators, the following two major material properties should be considered: high hardness for rebounding and/or gross mechanical deformation of the penetrator, and high toughness for effective energy absorption during the mechanical deformation (and heating) of the protecting materials.
Fabrication and Mechanical Properties of Alumina Nanoparticle Reinforced Magnesium Metal Matrix Composite by Stir Casting Method2018-28-00987/9/2018
In the present experimental investigation magnesium based alloy was prepared by mixing magnesium powder and aluminium powder in the ratio 65:35. The prepared magnesium alloy is used as the matrix material. Metal matrix composites were prepared by stir casting route. The composite was prepared by reinforcing 50 nm alumina nanoparticle so that the final composite contains 5, 10 and 15 wt.% alumina. Mechanical properties such as tensile strength, yield strength, impact strength and hardness were evaluated. Significant improvement was observed in impact strength and hardness value. The result showed that magnesium alloy with 5 wt.% alumina nanoparticle has a maximum impact strength of 25.2 J and hardness value 63.86 Hv respectively. Tensile strength and yield strength shows marginal increase in value.
T, Thirugnanasambandham, J, Chandradass, Sethupathi, P Baskara, Jesu Martin, Leenus
Coefficient of Thermal Expansion and Elastic Modulus of SIC P /AL 2 O 3 Ceramic Matrix Composites Prepared by Directed Metal Oxidation Process2018-28-00477/9/2018
The present paper, it is aimed to prepare SiCp/Al2O3 ceramic matrix composites using Directed Metal Oxidation process large enough dimension specimens for the measurement of physical properties. Continuous oxidation of an Aluminum alloy with suitable dopant along with a preform of SiC has lead to the formation of alumina matrix surrounding silicon carbide particulates. SiCp/Al2O3 ceramic matrix composites fabricated by the Directed Metal Oxidation process, possess required physical properties such as coefficient of thermal expansion (CTE) and elastic modulus, all at an affordable cost of fabrication. Al2O3 matrix composites reinforced with different volume fractions of SiC particulates were investigated for physical properties such as coefficient of thermal expansion (CTE) and elastic modulus. The composites with SiC volume fraction of 0.43 were found to possess a CTE as of as 5.0 x 10−6/K and an elastic modulus of 262 GPa.
Malkapuram, Dr Devaiah
Applying an Electric Field May Lead to More Resilient Dental ImplantsTBMG-323887/1/2018
Researchers have observed a way that the brittle nature of ceramics can be overcome as they sustain heavy loads, leading to more resilient structures such as dental implants.
Products of Tomorrow: June 2018TBMG-290436/1/2018
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
Experimental Evaluation of Transmission Loss-of-Lubrication TechnologiesF-0074-2018-128605/14/2018
ABSTRACT A Joint Aircraft Survivability Program (JASP) project was awarded in 2014 in order to accelerate the research and development on military helicopter transmission loss of lubrication survivability. This JASP project, "Helicopter Transmission Loss-of-Lubrication" was a collaboration between the US Army, US Navy, and NASA and completed in 2018. The approach for the effort was to first screen emerging technologies using coupon-level methods, then test those showing the most promise at the component level, and finally to downselect and evaluate these technologies at the system level. Several concepts to reduce heat generation, increase heat rejection, increase material tolerance to higher temperatures, and increase material resistance to damage were evaluated for this effort. Included in this evaluation were: a ceramic material for bearings, four different gear steels, various levels of gear surface roughness, six gear coatings, five lubricant and lubricant additive variations, and gearbox noble gas injection. After gear testing at the component level, isotropic superfinishing and ionic liquid lubricant additive were down selected as the two most suitable technologies for the system level testing. These technologies underwent loss of lubrication testing to failure in an intermediate gearbox from a standard configuration medium lift helicopter. A baseline loss of lubrication test, without these technologies, was also performed for comparison.
Berkebile, Stephen, Colon-Rivera, Radames, Fetty, Jason, Murthy, Nikhil, Radil, Kevin, Dykas, Brian
High Temperature Ceramic Matrix Composite Materials Research for Next Generation Army Propulsion SystemF-0074-2018-128715/14/2018
ABSTRACT Aviation propulsion system structures are subjected to challenging conditions such as extremely high velocities, ultra-high/low temperatures, and excessive dust/sand/smoke/volcanic ash conditions during military operations. Therefore, the research and development of high-performance engine materials with superior characteristics such as great mechanical strength, high fatigue resistance and creep resistance, good tolerance to wide temperature variations, and excellent resistance to corrosion and oxidation is essential to the evolution of highly robust and efficient propulsion systems without a compromise on capabilities, even in hostile environments. The goal of this collaborative program within United States Army Research Laboratory (ARL) is to establish a generalized fundamental physics-based approach and probabilistic-based lifing method to extrapolate thermal loading performance and material characterization results from high performance high temperature ceramic materials such as ceramic matrix composites (CMC) based flat specimens and engine component representative specimens. High temperature structural integrity and durability and probabilistic-based lifing assessment will be evaluated both analytically and experimentally under thermal shock, thermal cycling, and combined thermo-mechanical loadings. This paper presents the ARL CMC propulsion materials strategy in each of the identified thrust areas and present some results from some of the ongoing research at ARL and its research partners.
Ghoshal, Anindya, Mock, Clara, Murugan, Muthuvel, Nieto, Andy, Walock, Michael, Bravo, Luis, Pepi, Marc, Swab, Jeffrey, Hirsch, Samuel, Dowding, Robert
Ferroelectric Material Improves UltrasoundTBMG-289455/1/2018
Development of a theoretical basis for ultrahigh piezoelectricity in ferroelectric materials has led to a new material with twice the piezo response of any existing commercial ferroelectric ceramics.
Process Enables 3D Printing of Nanoscale Metal StructuresTBMG-287004/1/2018
In 3D printing — also known as additive manufacturing — an object is built layer-by-layer, allowing for the creation of structures that would be impossible to manufacture by conventional subtractive methods such as etching or milling.
Magnesium Alloy, Processes for Pretreatment and Prevention of Corrosion onAMSM3171 (Historical)2/25/2018
This specification covers general requirements for the apparatus, material, and procedures to be used in the processing of magnesium base alloys for the purpose of increasing their corrosion resistance and by producing surfaces suitable for organic paint finish systems.
AMS B Finishes Processes and Fluids Committee
Conductive, High-Toughness Oxides Deposited by Plasma Spray-Physical Vapor Deposition (PS-PVD)TBMG-283252/1/2018
Oxide coatings deposited in Glenn Research Center's Plasma Spray-Physical Vapor Deposition (PS-PVD) facility can be processed to be mechanically tough (erosion-resistant) and electrically conductive at room temperature. The electrically conductive phase contained within the oxide (MO2) coatings is a metastable suboxide (MO) that has not been formed in significant volume under any other known methods. Content of the electrically conductive phase can be varied in addition to the microstructure, which can be columnar, planar, or a combination of the two depending on the processing conditions. Upon exposing the material to moderate temperatures (>300 °C), the metastable phase is further oxidized (to MO2) and the material becomes insulating, but retains its high toughness and microstructure.
New Products & Services: December 2017 Aerospace Manufacturing & FabricationTBMG-2793912/1/2017
Processing and Characterization of Lightweight Syntactic MaterialsTBMG-2795912/1/2017
Conventional composite materials, in which a matrix material is reinforced by particulates, whiskers, and/or continuous fibers, have long been of interest as potential materials solutions to engineering needs. Typically, the benefits of these reinforcements are observed for cases of tensile loading, with only minimal improvement for cases of compressive loading. As a result, recent attention has grown in the use of hollow spheres as a potential reinforcement in metallic systems.
Flexible, Printable Electronics for Sensor ArraysTBMG-2778911/1/2017
Printable electronics — flexible circuitry that is deposited on some type of plastic substrate — has been a major area of research for decades. But the ability to print the substrate itself greatly increases the range of devices the technique can yield.
The Power of Ultrasonic Piezo Transducers for Medical ApplicationsTBMG-2771810/1/2017
ADHESIVES: The Importance of CTE for Assembly ReliabilityTBMG-2772610/1/2017
Adhesive compounds play a critical role in the fabrication of assemblies for electronic, optical, and mechanical systems. In securing multiple components into a single structure, bonding agents such as epoxies and silicones help stabilize the assembly despite the various sources of stress that can arise in the target application. Among these stress factors, differences in thermal expansion of the components of an assembly represent one of the most insidious and potentially damaging sources of stress.
Ultralight, Scalable, High-Temperature-Resilient Ceramic Nanofiber SpongesTBMG-275229/1/2017
Researchers have made ultralight, highly porous, compressible, and heat-resistant sponge-like materials from nanoscale ceramic fibers. The highly deformable material is made by tangling ceramic nanofibers into a sponge. The method used is inexpensive and scalable for making large quantities.
Composite Materials Handbook Volume 5 - Revision AR-4266/29/2017
The fifth volume of this six-volume compendium publishes technical guidance and properties on ceramic matrix composite material systems. The selected guidance on technical topics related to this class of composites includes material selection, processing, characterization, testing, data reduction, design, analysis, quality control, application, case histories, and lessons learned of typical ceramic matrix composite materials. Volume 5, which covers ceramic matrix composites, supersedes MIL-HDBK-17-5 of June 17, 2002. The Composite Materials Handbook, referred to by industry groups as CMH-17, is an engineering reference tool that contains over 1,000 records of the latest test data for polymer matrix, metal matrix, ceramic matrix, and structural sandwich composites. CMH-17 provides information and guidance necessary to design and fabricate end items from composite materials. It includes properties of composite materials that meet specific data requirements as well as guidelines for design, analysis, material selection, manufacturing, quality control, and repair. The primary purpose of the handbook is to standardize engineering methodologies related to testing, data reduction, and reporting of property data for current and emerging composite materials. It is used by engineers worldwide in designing and fabricating products made from composite materials.
Composites and Metal Bonding GlossaryAIR4844C (Historical)6/20/2017
The following terminology has been generated by the ATA/IATA/SAE Commercial Aircraft Composite Repair Committee (CACRC) and provides terminology for design, fabrication, and repair of composite and bonded metal structures.
AMS CACRC Commercial Aircraft Composite Repair Committee
Hybrid Ceramic Bearing Fatigue Testing for the Future Advanced Rotorcraft Drive System ProgramF-0073-2017-121495/9/2017
ABSTRACT Today's rotorcraft transmissions predominately utilize fully metallic bearings where both the raceways and rolling elements are metal. Ceramic bearing materials offer the potential for meeting the demand for weight reduction and increased power-to-weight ratios. Hybrid ceramic bearings incorporate both ceramic and metallic components forming an assembly that lends itself to improvements in weight, corrosion resistance, reduced friction, and improved surface characteristics. Typically, hybrid ceramic bearings consist of ceramic rolling elements and metallic raceways. Hybrid ceramic bearings have demonstrated feasibility for both remotely and non-remotely monitored applications in rotorcraft drive systems. Characterization of potential material combinations of hybrid ceramic bearings is needed to guide the design of hybrid ceramic bearings for use in future and modified rotorcraft transmissions. This research, conducted under the Future Advanced Rotorcraft Drive System (FARDS) program, examined multiple bearing material combinations and characterized them in fatigue testing. Hybrid ceramic bearing material combinations showed increased performance when compared to fully metallic bearing material combinations. Favorable results indicate that hybrid ceramic bearings can have immediate impact on rotorcraft transmission designs.
Anderson, Cody, Ponten, Lars, Fetty, Jason, Kiamanesh, Roozbeh, Baker, Treven
Ceramic Rolling Element Damage Sensitivity and Gearbox System ResponseF-0073-2017-121545/9/2017
ABSTRACT The rotorcraft industry is constantly pushing for higher temperatures, speeds, and loads, while simultaneously minimizing weight. Hybrid bearings (steel rings with ceramic rolling elements) offer improved performance over all-steel bearings plus significant weight savings. However, there are still concerns about using them within the aerospace industry. Two of the main concerns regarding hybrid bearings are that any manufacturing defects may lead to premature failure and that failures may be catastrophic in nature. In this manuscript, recent research performed on the sensitivity of hybrid bearings to preexisting damage and the sensitivity of an engine gearbox to hybrid bearing failure is presented. First, elemental testing was performed on ceramic rolling elements during which it was found that it is difficult to damage a ceramic rolling element and that they are far more tolerant of damage than was previously believed. Next, damaged balls were run in a single ball test rig at operating stresses to determine number of cycles to failure as a function of damage severity and predict time to failure in the application. Finally, the damaged rolling elements were run in a gearbox under maximum normal operating conditions and produced a soft failure within 15% of the time predicted by single ball testing.
Allison, Bryan, Kozachyn, Mark, Lunz, Tom, Monaghan, Kyle
Highly Porous and Mechanically Strong Ceramic Oxide AerogelsTBMG-268365/1/2017
NASA's Glenn Research Center (GRC) has developed and produced ultra-lightweight polymer cross-linked aerogels (X-Aerogels). These mechanically robust, highly porous, low-density materials are three times denser than native aerogels, but more than 100 times stronger. Aerogels are ultra-lightweight glass foams with extremely small pores (on the order of 10 to 50 nanometers). These materials are extremely good thermal insulators, with R values ranging from 2 to 10 times higher than polymer foams. Unlike multilayer insulation, aerogels do not require a high vacuum to maintain their low thermal conductivity, and can function as good thermal insulators at ambient pressure. In addition, they are good electrical insulators and have low refractive indices, both approaching values close to air. Aerogels are also excellent vibration-damping materials. Traditional aerogels, however, suffer fragility and poor environmental durability.
A Modeling Analysis of Fibrous Media for Gasoline Particulate Filters2017-01-09673/28/2017
With an emerging need for gasoline particulate filters (GPFs) to lower particle emissions from gasoline direct injection (GDI) engines, studies are being conducted to optimize GPF designs in order to balance filtration efficiency, backpressure penalty, filter size, cost and other factors. Metal fiber filters could offer additional designs to the GPF portfolio, which is currently dominated by ceramic wall-flow filters. However, knowledge on their performance as GPFs is still limited. In this study, modeling on backpressure and filtration efficiency of fibrous media was carried out to determine the basic design criteria (filtration area, filter thickness and size) for different target efficiencies and backpressures at given gas flow conditions. Filter media with different fiber sizes (8 - 17 μm) and porosities (80% - 95%) were evaluated using modeling to determine the influence of fiber size and porosity. A comparison of design criteria for fibrous filters and their ceramic counterparts is also discussed.
Liu, Xin, Kim, Jeong, Chanko, Timothy, Lambert, Christine, Pakko, James
Development of a New Ceramic Substrate with Gas Flow Control Functionality2017-01-09193/28/2017
Emission regulations in many countries and regions around the world are becoming stricter in reaction to the increasing awareness of environment protections, and it has now become necessary to improve the performance of catalytic converters to achieve these goals. A catalytic converter is composed of a catalytically active material coated onto a ceramic honeycomb-structured substrate. Honeycomb substrates play the role of ensuring intimate contact between the exhaust gas and the catalyst within the substrate’s flow channels. In recent years, high-load test cycles have been introduced which require increased robustness to maintain low emissions during the wide range of load changes. Therefore, it is extremely important to increase the probability of contact between the exhaust gas and catalyst. To achieve this contact, several measures were considered such as increasing active sites or geometrical surface areas by utilizing substrates with higher cell densities or larger volumes. These measures, however, led to greater consumption of precious metals and decreased vehicle power by increasing pressure losses. Therefore, a new concept substrate, which focuses on gas flow redistribution, has been developed to overcome these negatives. The key points of this development include a compound cell structure design which consists of a higher cell density area in the center portion of the substrate completely surrounded by a lower cell density area and optimization of the cell design for each portion to improve the efficiency of the catalytic converter. As a result, this newly developed honeycomb substrate shifts the trend line relationship of catalytic performance and pressure loss to a higher level. In addition, it reduces precious metal usage, as well as the volume of catalytic converters while maintaining catalytic performance equivalent to that of a conventional honeycomb substrate (400 cell density).
Yoshida, Takeru, Suzuki, Hiromasa, Aoki, Yuki, Hayashi, Naohiro, Ito, Kenichi
The Heavy Impact of Advanced Lightweight MaterialsTBMG-265143/1/2017
Historically, high-strength materials have been heavy and dense. The need for high-strength but lightweight materials has become more widespread when designing everything from vehicles and aircraft, to buildings and wind turbines. These advanced materials are enabling engines to operate efficiently at higher temperatures, use less fuel, and emit fewer pollutants, as well as finding uses in many other applications.
Method for Fabricating Diamond-Dispersed, Fiber-Reinforced Composite Coating on Low-Temperature Sliding Thrust Bearing InterfacesTBMG-263462/1/2017
Innovators at NASA's Glenn Research Center have developed a method for fabricating a fiber-reinforced diamond composite coating on the surfaces of sliding thrust bearings at low and cryogenic temperatures. The innovative composite coating is a mixture of diamond particles, organic chemicals, and fibers or fabrics. The diamond particles provide high hardness, and the fibers and binding matrix provide high-fracture toughness. Glenn's fabrication method can be tailored to meet a range of performance requirements for lightweight, low-temperature sliding thrust bearing applications. For example, the volume fraction of diamond particles can be increased to enhance the hardness of the composite coating, or the volume fraction of binding matrix can be increased to enhance its crack or fracture resistance. Glenn's method offers a diamond composite coating that is more cost-effective, wear-resistant, and fracture-tough than existing alternatives.
Multiscale, Multiphysics Computational Chemistry Methods Based on Artificial Intelligence Integrated Ultra-Accelerated Quantum Molecular Dynamics for the Application to Automotive Emission Control2016-32-006711/8/2016
On the basis of extensive experimental works about heterogeneous catalysts, we developed various software for the design of automotive catalysts such as Ultra-Accelerated Quantum Chemical Molecular Dynamics (UA-QCMD), which is 10 million times faster than the conventional first principles molecular dynamics, mesoscopic modeling software for supported catalysts (POCO2), and mesoscopic sintering simulator (SINTA) to calculate sintering behavior of both precious metals (e.g., Pt, Pd, Rh) and supports (e.g., Al2O3, ZrO2, CeO2, or CeO2-ZrO2). We integrated the previous programs in a multiscale, multiphysics approach for the design of automotive catalysts. The method was efficient for a variety of important catalytic reactions in the scope of the automotive emission control. We demonstrated the efficiency of our approach by comparing our data with experimental results including both simple laboratory experiments and chassis dynamometer exhaust gas emission control experiments. We also demonstrated that the UA-QCMD method is an efficient tool for the estimation of mesoscopic sintering activation energies for both precious metals and supports. On the basis of our successful applications of the UA-QCMD to various important chemical processes of exhaust emission controls and sintering predictions of both precious metals and support of automotive catalysts, we employed in the present study artificial intelligence to determine fundamental parameters from all electron density functional methods and thermodynamic results. This new technique was proven highly efficient for optimizing parameters necessary in our simulations.
Miyamoto, Akira, Inaba, Kenji, Ishizawa, Yukie, Sato, Manami, Komuro, Rei, Sato, Masashi, Sato, Ryo, Bonnaud, Patrick, Miura, Ryuji, Suzuki, Ai, Miyamoto, Naoto, Hatakeyama, Nozomu, Hariyama, Masanori
Development of Aluminum Composite Automotive Brake Rotors2016-01-19379/18/2016
Aluminum metal matrix composite brake rotors with a selective ceramic function reinforcement gradient (FRG) have been developed for automotive applications. This paper will highlight the design, manufacturing, and testing of the rotors. Weight saving of an aluminum composite rotor in comparison to an industry standard cast iron rotor is 50-60%. With this material change comes design considerations to manage rotor temperature, rotor surface integrity, and friction. Manufacturing methods to meet these design constraints were needed to develop a viable high performance aluminum composite rotor. High pressure squeeze casting with soluble coring techniques were developed to incorporate the selective FRG MMC rotors. Dynamometer testing was performed, concentrating on brake friction and temperature to evaluate the macro and micro interfaces in the rotors. The rotors’ testing results indicate that a functional reinforced aluminum metal matrix composite rotor is viable option for front and rear brake applications in the automotive and commercial trucking market.
Erva, Taylor, Loukus, Adam, Luskin, Luke
Flexible Ablator for Thermal ProtectionTBMG-253509/1/2016
NASA has developed a class of low-density, flexible ablators that can be fabricated into heat-shields capable of being packaged, stowed, and deployed in space. The key characteristics of this new ablative thermal protection system (TPS) are its flexibility, conformability, and tailor-ability. Flexibility allows the material to be stowed in the shroud of a launch vehicle and deployed in space, without compromising functionality. Conformability allows the material to be attached to a curved surface without precise and expensive machining. Tailor-ability allows the density and composition to be optimized for the requirements. This flexible TPS can be used to cover and thermally protect a large, blunt shape that provides aerodynamic drag during hyper-velocity atmospheric flight. It can be used with minimal modification for large aeroshells whose deployment relies mainly on mechanical means and through inflation. Such devices are called Hypersonic Inflatable Aerodynamic Decelerators (HIADs). Large blunt body aeroshells may be used to deliver large payloads (40 metric tons) to the surface of Mars.
Toughened Uni-piece Fibrous Reinforced Oxidation-Resistant Composite (TUFROC)TBMG-253539/1/2016
The Toughened Uni-piece Fibrous Reinforced Oxidation-Resistant Composite (TUFROC) allows for much more affordable and sustainable operations involving Space Launch Services and other systems that utilize Earth re-entry vehicles. TUFROC has an exposed surface design and appropriate materials combination that will allow a space vehicle to survive both the mechanical stresses during launch and the extreme heating and stress of re-entry. It provides a thermal protection tile attachment system that is suitable for not only spacecraft applications, but also could be used where there are extreme heating environments [up to 3100 °F for 5 to 10 minutes and 3600 °F, and possibly higher, for very short time intervals (one-minute or less)].
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