Materials

Hydrolytic Stability of Polyurethane-Coated Fabrics Used for Collapsible Fuel Storage Containers

Collapsible fabric fuel tanks have provided critical tactical bulk petroleum storage for military operations for over 50 years. Beginning in the 1940s with the 900 to 3,000-gallon pillow tanks, collapsible fabric tanks have evolved into the primary tactical fuel storage vessels now used by all of the military services.

Posted in: Briefs, Aerospace, Defense, Coatings & Adhesives, Materials, Containers, Storage, Coatings Colorants and Finishes, Fabrics, Fuel tanks, Military vehicles and equipment
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Materials Design Principles for the Dynamic Fracture of Laminar Composite Structures

Crack bridging (e.g., from stitches or pins) and friction have profound and potentially very useful effects on delamination crack growth, controlling growth rates (damage levels) and the energy absorbed. However, the implications for structural design principles have remained quite obscure. The difficulty is that no simple analogue of crack toughness, which underpins static structural design, exists for dynamic cases with large-scale bridging effects. The external shape of the structure and the loading configuration dictate stress waves, frictional contact zones, and crack tip stress intensity factors in a way that is very difficult to approach, other than by brute case-specific numerical simulation. The problem is compounded by the common occurrence of multiple cracking, a complexity that is rarely entertained in laboratory fracture specimen design. Physically sound material models for the important structural problem of multiple, nonlinear cracking in laminated structures with large-scale bridging due to friction and reinforcement had previously remained undeveloped, in spite of the technological importance of these systems.

Posted in: Briefs, Aerospace, Defense, Electronics & Computers, Information Technology, Materials, Finite element analysis, Composite materials
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Development of Hydrophobic Coatings for Water-Repellent Surfaces Using Hybrid Methodology

Coatings that impart hydrophobic properties are of considerable interest. For applications such as aircraft windows, optical components, protective eyewear, and clothing, this type of surface is desired for the material to be soil-repellent and waterresistant. A prime model of a surface with these characteristics can be found in nature – the leaves of the lotus flower have super-hydrophobic properties as a means of self-cleaning.

Posted in: Briefs, Aerospace, Defense, Coatings & Adhesives, Materials, Windows and windshields, Optics, Coatings Colorants and Finishes, Protective equipment
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Carbon-Fiber Concept Trailer From Great Dane Cuts Weight by 4000 lb

The Walmart Advanced Vehicle Experience is a prototype tractor-trailer developed to demonstrate the possibilities of future transport, and the truck is not the only place where innovation reigns. The trailer body is built almost exclusively with carbon fiber, and it incorporates other technologies such as advanced adhesives and low-profile LED lighting. Read more at http://articles.sae.org/13507.

Posted in: Articles, Aerospace, Defense, Coatings & Adhesives, Materials, Transportation
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Fabricating Porous Systems for Super-Dense Memories and Sensors

This project was dedicated to solving basic scientific issues and developing the scientific basis that underlies the improvement of super-dense memories, towards the terabit-per-square-inch goal and the engineering of chemical and biological sensors. Both applications rely on porous materials. Among them, porous alumina has demonstrated to provide major improvements in these two diverse applications.

Posted in: Briefs, Materials, Computer software / hardware, Sensors and actuators, Fabrication, Aluminum alloys
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Toward Smarter Manufacturing and Materials

At the U.K.’s new Advanced Manufacturing Research Center, engineers and innovators have at their disposal some of the world’s most advanced design and manufacturing assets for precision engineering.

by Richard Gardner

For well over a century the word “Sheffield” has been synonymous with high-quality steel products, ranging from cutlery to heavy engineering products for bridges, railways, and aircraft. Following many years of industrial decline as much traditional large-scale manufacturing departed in the direction of low-wage Asian economies, the region suffered accordingly.

Posted in: Articles, Aerospace, Defense, Materials, Production engineering, Composite materials
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More Electric, Integrated Fuel Systems

Global warming and environmental friendliness considerations have recently been key for multiple global industries. In the commercial aviation industry, reduction of aircraft emissions, including CO2 and noise, is an urgent priority. Both aircraft and aircraft engine manufacturers are striving to improve design to accommodate the needs of commercial airlines. Engine manufacturers in particular have worked long and hard to improve each engine component, e.g., compressors, turbines, combustors, etc.

Posted in: Articles, Aerospace, Defense, Materials, Emissions control, Electric motors, Engine components, Fuel pumps, Commercial aircraft
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Optically Transparent EMI Shielding for Defense and Aerospace Applications

Modern electronic devices and computing equipment are often integrated with wireless capabilities which utilize multi-bands for high speed communication, as well as high speed circuits and high definition graphical displays that operate at a wide range of frequencies. As such, hardware systems are becoming increasingly complex, resulting in products that are highly sensitive to electromagnetic interference (EMI). The vulnerability to EMI is further heightened when multiple components are packed close together within the device due to space, size and weight constraints. As such, traditional shielding methods that employ materials like thick metal Faraday cages are not always practical due to their heavy weight and bulkiness. Despite its complexity, managing this interference and increasing the resilience of components, interconnects and subsystems within the device is crucial to ensuring reliability and functionality.

Posted in: Articles, Aerospace, Defense, Materials, Avionics, Electromagnetic compatibility, Electronic equipment, Optics, Displays, Military aircraft
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Pumped Two-Phase Cooling for Thermal Management of High Heat Flux Electronics

Pumped two-phase cooling provides a compact, low pumping power option for thermal management in high heat flux applications (300-500W/cm2). Compared to single-phase convection, significantly higher heat transfer coefficients can be achieved at substantially lower flowrates. Two-phase cooling also provides a high degree of isothermality, which is important in many applications such as lasers whose emission wavelengths are temperature-dependent.

Posted in: Articles, Aerospace, Defense, Materials, Electronic equipment, Thermal management, Coatings Colorants and Finishes
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Thermal Simulation and Testing of Expanded Metal Foils for Lightning Protection

With the implementation of major aircraft structures fabricated from carbon fiber reinforced plastic materials, lightning protection has become a more complicated issue for designers and engineers to solve.

Cracking of coatings and surface layers is evident on a variety of structures including buildings, automobiles, and aircraft. In some situations, the appearance of the coated or painted surface is degraded and the aesthetic appeal is lessened. However, in others, such as composite aircraft structures, paint cracking is both aesthetically undesirable and potentially deleterious from the electromagnetic effects aspect.

Posted in: Articles, Aerospace, Defense, Materials, Test & Measurement, Computer simulation, Coatings Colorants and Finishes, Composite materials, Lightning protection, Thermal testing
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