Materials

Composites Self-Heal at Very Low Temperatures

Scientists developed a method of allowing materials, commonly used in aircraft, to self-heal cracks at temperatures well below freezing. A healing efficiency of more than 100% at temperatures of -60 °C was obtained in a glass fiber-reinforced laminate, but the technique could be applied across a majority of self-healing composites.

Posted in: News, Defense, Composites, Materials
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Army Scientists Synthesize High-Performing Energetic Material

Scientists at the U.S. Army Research Laboratory recently synthesized a new material called bis-isoxazole tetranitrate, or BITN, with potential applications in propulsion and lethality.

Posted in: News, Aerospace, Defense, Materials, Propulsion
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Turbine Flow Meters: Technology-of-Choice for Measuring Critical Fluid Flow Applications

The aerospace industry has some of the most difficult operating conditions imaginable. Sensors of all kinds used in this industry must stand up to the environment and be able to perform under harsh conditions, fit in extremely tight spaces, and have electronics that can compensate for variable conditions in order to provide precise, repeatable results.

Posted in: Articles, Aerospace, Manufacturing & Prototyping, Materials, Computational fluid dynamics, Downsizing, Sensors and actuators
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Managing the Impact of Nanomaterials in Aerospace Manufacturing

As the aerospace industry continues to make improvements to safety, comfort and affordability of aircraft, nanomaterials are making their way into more elements of aircraft structure, electronics, glass, textiles and other components. While these materials provide tangible advantages in terms of weight, strength, speed and comfort, their effect on the humans that come into contact with them is still being studied and debated.

Posted in: Articles, Aerospace, Composites, Aircraft structures, Human factors, Materials properties, Nanomaterials
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Structural Composites with Tuned EM Chirality

Several metamaterials show promise in providing advanced radio frequency control.

Work on structural composites with tunable chiral elements has produced electronically tunable overall chiral composites, mechanically tunable chiral composites, flat lenses with soft hyperbolic focusing due to indefinite overall permittivity, a tunable flat lens based on chiral elements with adjustable focal spot based on applied mechanical deformation, and a three-phase periodic composite that demon strates positive and negative refraction, depending on the input frequency and angle of incidence. A MATLAB code directly computes the group velocity and pass bands for a given set of wave vectors, and generates an intuitive plot for quick, but thorough analysis.

Posted in: Briefs, Aerospace, Defense, Materials, Analysis methodologies, Composite materials
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Advanced, Single-Polymer, Nanofiber-Reinforced Composite

Continuous nanofibers provide unique advantages for future structural nanocomposites.

A strategic goal of the U.S. Air Force is to be able to deliver munitions to targets anywhere around the globe in less than an hour. This will require very high speeds and novel lightweight and temperature-resistant materials. Nanocomposites are promising emerging materials for structural and functional applications due to unique properties of their nanoscale constituents. However, the currently available nanocomposites based mostly on nanoparticles lack the high strength and stiffness required for structural applications.

Posted in: Briefs, Aerospace, Defense, Materials, Composite materials, Fibers, Nanomaterials, Polymers
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Quantitative Diagnostics of Multilayered Composite Structures with Ultrasonic Guided Waves

This nondestructive methodology inspects a sound-absorbing composite structural system consisting of polymeric and metallic materials.

Aging infrastructure has a major impact on safety, increasing the need to assess damage severity. Machinery, systems, and components such as airplanes, cars, pumps, and pipes in the oil and chemical industry are subject to varying cyclic service loading and environmental influences. Sometimes multilayered coatings are used, requiring a high-resolution inspection to confirm the presence of a defect such as a delamination, and accurately locate and quantify its size. Highly attenuating materials may significantly increase the inspection time while limiting defect observability. Guided waves have been recognized as having excellent potential for nondestructive inspection. However, the presence of viscoelastic coatings used for corrosion protection is one of the major obstacles for guided wave inspection.

Posted in: Briefs, Aerospace, Defense, Manufacturing & Prototyping, Materials, Diagnostics, Composite materials, Inspections, Non-destructive tests
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Reactive, Multifunctional, Micellar, Composite Nanoparticles for Destruction of Bio-Agents

Multifunctional composites have been investigated for destruction of bio-agents. These materials’ unique properties at the nano scale, including their abrasive character and high surface area leading to very close contact with cells, and their unusual surface morphology leading to high surface reactivity, make them promising biocides. Nanoparticles can also be prepared in a variety of forms such as powders, slurries, pellets, and membranes, making them more convenient and widely applicable for bio-agent destruction. Additionally, nanoparticles can generally be easily stored, which increases their flexibility.

Posted in: Briefs, Aerospace, Defense, Materials, Composite materials, Nanomaterials
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Thermal Response of Ultra-High Molecular Weight Polyethylene (UHMWPE) Materials in a Flash Flame Test

Testing was performed on Ultra-High Molecular Weight Polyethylene (UHMWPE) fabric and composite material in a flash flame environment when protected by a flame-resistant (FR) fabric outer layer. UHMWPE material has excellent ballistic protection properties, but has generally not been considered for ballistic protection garments due to its low melting point. This research was conducted to determine if UHMWPE materials could be considered for use in the recently developed protective undergarment (PUG) if worn beneath an FR uniform.

Posted in: Briefs, Aerospace, Defense, Materials, Composite materials, Fabrics, Polymers, Thermal testing
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Silicon Carbide Foam

Silicon carbide (SiC) foam from Goodfellow (Coraopolis, PA) provides the exceptional hardness, high-temperature durability and performance of solid silicon carbide, but in a lightweight foam structure. The matrix of cells and ligaments of silicon carbide foam is completely repeatable, regular and uniform throughout the material, yielding a rigid, highly porous and permeable structure with a controlled density of metal per unit volume. Characteristics of SiC foam include: exceptional hardness (Mohs 9) and resistance to wear and corrosion; can withstand temperatures up to 2200°C; high thermal and electrical conductivity; and low thermal expansion.

Silicon carbide foam is available from stock in a standard pore size of 24 pores per centimeter (60 ppi), with a bulk density of 0.29 g.cm-3, a porosity of 91% and a thickness of 10mm.

For Free Info Visit http://info.hotims.com/55588-510

Posted in: Products, Defense, Consumer Product Manufacturing, Materials
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