Results for “building materials” — Page 32

NASA NTRS1983

Designing Glass Panels for Economy and Reliability

Analytical method determines probability of failure of rectangular glass plates subjected to uniformly distributed loads such as those from wind, earthquake, snow, and deadweight. Developed as aid in design of protective glass covers for solar-cell arrays and solar collectors, method is also useful in estimating the reliability of large windows in buildings exposed to high winds and is adapted to nonlinear stress analysis of simply supported plates of any elastic material.

Moore, D. M.↗

NASA NTRS1983

Hot-Melt Adhesive Attachment System

Adhesive system is as effective on Earth as in space. Fiberglass cloth mounted in head assembly. When adhesive reaches melt temperature head is attached to metals composites, ceramics, and other materials. Once attached, head cooled rapidly for quick stick. Used to tether tools or attach temporary scaffolding to walls, buildings, or beams.

Fox, R. L.↗

NASA NTRS1991

Stirling engine: Available tools for long-life assessment

A review is presented for the durability approaches applicable to long-time life assessment of Stirling engine hot-section components. The crucial elements are experimental techniques for generating long-time materials property data (both monotonic and cyclic flow and failure properties); analytic representations of slow strain rate material stress-strain response characteristics (monotonic and cyclic constitutive relations) at high temperatures and low stresses and strains; analytic creep-fatigue-environmental interaction life prediction methods applicable to long lifetimes at high temperatures and small stresses and strains; and experimental verification of life predictions. Long-lifetime design criteria for materials of interest are woefully lacking. Designing against failures due to creep, creep-rupture, fatigue, environmental attack, and creep-fatigue-environmental interaction will require considerable extrapolation. Viscoplastic constitutive models and time-temperature parameters will have to be calibrated for the hot-section materials of interest. Analysis combined with limited verification testing in a short-time regime will be required to build confidence in long-lifetime durability models.

Halford, Gary R.↗

NASA NTRS1991

Stirling engine - Available tools for long-life assessment

A review is presented for the durability approaches applicable to long-time life assessment of Stirling engine hot-section components. The crucial elements are experimental techniques for generating long-time materials property data (both monotonic and cyclic flow and failure properties); analytic representations of slow strain rate material stress-strain response characteristics (monotonic and cyclic constitutive relations) at high temperatures and low stresses and strains; analytic creep-fatigue-environmental interaction life prediction methods applicable to long lifetimes at high temperatures and small stresses and strains; and experimental verification of life predictions. Long-lifetime design criteria for materials of interest are woefully lacking. Designing against failures due to creep, creep-rupture, fatigue, environmental attack, and creep-failure-environmental interaction will require considerable extrapolation. Viscoplastic constitutive models and time-temperature parameters will have to be calibrated for the hot-section materials of interest. Analysis combined with limited verification testing in a short-time regime will be required to build confidence in long-lifetime durability models.

Halford, Gary R.↗

NASA NTRS1995

Numerical Solution of Multi-Dimensional Hyperbolic Conservation Laws on Unstructured Meshes

The lecture material will discuss the application of one-dimensional approximate Riemann solutions and high order accurate data reconstruction as building blocks for solving multi-dimensional hyperbolic equations. This building block procedure is well-documented in the nationally available literature. The relevant stability and convergence theory using positive operator analysis will also be presented. All participants in the minisymposium will be asked to solve one or more generic test problems so that a critical comparison of accuracy can be made among differing approaches.

Barth, Timothy J.↗

NASA NTRS2004

Reading Through Paint

Two-dimensional data matrix symbols, which contain encoded letters and numbers, are permanently etched on items for identification. They can store up to 100 times more information than traditional bar codes. While the symbols provide several advantages over bar codes, once they are covered by paint they can no longer be read by optical scanners. Since most products are painted eventually, this presents a problem for industries relying on the symbols for identification and tracking. In 1987, NASA s Marshall Space Flight Center began studying direct parts marking with matrix symbols in order to track millions of Space Shuttle parts. Advances in the technology proved that by incorporating magnetic properties into the paints, inks, and pastes used to apply the matrix symbols, the codes could be read by a magnetic scanner even after being covered with paint or other coatings. NASA received a patent for such a scanner in 1998, but the system it used for development was not portable and was too costly. A prototype was needed as a lead-in to a production model. In the summer of 2000, NASA began seeking companies to build a hand-held scanner that would detect the Read Through Paint data matrix identification marks containing magnetic materials through coatings.

Source record↗

NASA NTRS2014

Crack Growth Behavior in the Threshold Region for High Cycle Fatigue Loading

The research results described in this paper presents a new understanding of the behavior of fatigue crack growth in the threshold region. It is believed by some crack growth experts that the ASTM load shedding test method does not produce true or valid threshold properties. The concern involves the observed fanning of threshold region da/dN data plots for some materials in which the low R-ratio data fans out or away from the high R-ratio data. This data fanning or elevation of threshold values is obviously caused by an increase in crack closure in the low R-ratio tested specimens. This increase in crack closure is assumed by some investigators to be caused by a plastic wake on the crack surfaces that was created during the load shedding test phase. This study shows that the increase in crack closure is the result of an extensive occurrence of crack bifurcation behavior in some materials, particularly in aluminum alloys, when the crack tip cyclic yield zone size becomes less than the grain size of the alloy. This behavior is related to the high stacking fault energy (SFE) property of aluminum alloys which results in easier slip characteristics. Therefore, the particular fanning behavior in aluminum alloys is a function of intrinsic dislocation property of the materials and that the fanned data represents valid material properties. However, for corrosion sensitive steel alloys used in this study the fanning was caused by a build-up of iron oxide at the crack tip from fretting corrosion.

Forman, Royce G.↗

NASA NTRS2015

3D Printing Multi-Functionality: Embedded RF Antennas and Components

Significant research and press has recently focused on the fabrication freedom of Additive Manufacturing (AM) to create both conceptual models and final end-use products. This flexibility allows design modifications to be immediately reflected in 3D printed structures, creating new paradigms within the manufacturing process. 3D printed products will inevitably be fabricated locally, with unit-level customization, optimized to unique mission requirements. However, for the technology to be universally adopted, the processes must be enhanced to incorporate additional technologies; such as electronics, actuation, and electromagnetics. Recently, a novel 3D printing platform, Multi3D manufacturing, was funded by the presidential initiative for revitalizing manufacturing in the USA using 3D printing (America Makes - also known as the National Additive Manufacturing Innovation Institute). The Multi3D system specifically targets 3D printed electronics in arbitrary form; and building upon the potential of this system, this paper describes RF antennas and components fabricated through the integration of material extrusion 3D printing with embedded wire, mesh, and RF elements.

antennas↗

NASA NTRS2017

Shape Morphing Adaptive Radiator Technology (SMART) Updates to Techport Entry

The Shape-Morphing Adaptive Radiator Technology (SMART) project builds off the FY16 research effort that developed a flexible composite radiator panel and demonstrated its ability to actuate from SMA's attached to it. The proposed FY17 Shape-Morphing Adaptive Radiator Technology (SMART) project's goal is to 1) develop a practical radiator design with shape memory alloys (SMAs) bonded to the radiator's panel, and 2) build a multi-panel radiator prototype for subsequent system level thermal vacuum tests. The morphing radiator employs SMA materials to passively change its shape to adapt its rate of heat rejection to vehicle requirements. Conceptually, the radiator panel has a naturally closed position (like a cylinder) in a cold environment. Whenever the radiator's temperature gradually rises, SMA's affixed to the face sheet will pull the face sheet open a commensurate amount - increasing the radiators view to space and causing it to reject more heat. In a vehicle, the radiator's variable heat rejection capabilities would reduce the number of additional heat rejection devices in a vehicle's thermal control system. This technology aims to help achieve the required maximum to minimum heat rejection ratio required for manned space vehicles to adopt a lighter, simpler, single loop thermal control architecture (ATCS). Single loop architectures are viewed as an attractive means to reduce mass and complexity over traditional dual-loop solutions. However, fluids generally considered safe enough to flow within crewed cabins (e.g. propylene glycol-water mixtures) have much higher freezing points and viscosities than those used in the external sides of dual loop ATCSs (e.g. Ammonia and HFE7000).

Erickson, Lisa↗

NASA NTRS2018

Fatigue Characteristics of Additively Manufactured Aerospace Materials

This presentation documents the fatigue properties of three additive manufactured (AM) metallic systems (Ti-6-4, GRC op-84, and Alloy 718) used by NASA in various aerospace applications. These alloys were produced using the powder bed method, with the titanium alloy using an electron beam melting (EBM) and the other two alloys using selective laser melting systems (SLM). For each material a large matrix of fatigue tests were conducted and the fatigue characteristics compared to their conventionally manufactured counterparts. Build orientations and resulting microstructures are discussed with respect to the tested mechanical properties.

Lerch, Brad↗

NASA NTRS2019

NASA Centennial Challenge: 3D Printed Habitat, Phase 3 Final Results

NASA's Centennial Challenges program uses prize competitions with the goal of accelerating innovation in the aerospace industry. Competitions in the Centennial Challenges portfolio have previously focused on advancements in space robotics, regolith excavation, bio-printing, astronaut suit design, small satellites, and solar-powered vehicles. NASA's Three Dimensional (3D) Printed Habitat Centennial Challenge represents a partnership between NASA and the non-profit partner: Bradley University, with co-sponsors Caterpillar, Bechtel, Brick and Mortar Ventures, the American Concrete Institute, and the United States Army Corps of Engineers (USACE) Engineer Research and Development Center (ERDC) to spur development in automated additive construction technologies. The challenge asks teams to design and construct a scaled and simulated Martian habitat using indigenous materials and large scale 3D automated printing systems. Phase 1 of the competition, held in 2015, was an architectural design competition for habitat concepts that could be 3D printed. Phase 2, completed in 2017, asked teams to develop feedstocks from indigenous materials and hydrocarbon polymer recyclables, and demonstrate automated printing systems to manufacture these feedstocks into test specimens to assess mechanical strength. This paper will discuss the Phase 3 competition, focusing on technology outcomes that can potentially be infused into both terrestrial and planetary construction applications. The Phase 3 competition was divided into two sub-competitions: 1) virtual construction, where teams created a high fidelity building information model (BIM) of their 3D-printed habitat design and 2) the construction competition, which required teams to 3D print a structural foundation and subject materials samples to freeze/thaw testing and impact testing (level 1), produce a habitat element and complete a hydrostatic test (level 2), and additively manufacture a 1:3 scale habitat onsite in a head to head competition at Caterpillar, inc.'s Edwards Demonstration & Learning Center near Peoria, Illinois over the course of three days (level 3). While the Phase 2 competition focused primarily on the development of novel feedstocks and robotic printing systems, Phase 3 emphasized the scale-up of these systems and autonomous operation (demonstrating the capability to operate systems on precursor missions prior to the arrival of crew, or terrestrially in field operation settings where human tending of a manufacturing system may be limited). The Phase 3 virtual construction levels yielded a number of novel habitat designs, including both modular habitats and vertically-oriented habitat concepts. The Phase 3 construction competition also challenged teams to autonomously place penetrations and interfacing elements in additively manufactured structures. The paper will emphasize potential applications for the new materials and technologies developed under the umbrella of the competition within NASA's portfolio and in Earth-based applications such as disaster response and infrastructure improvement.

Construction↗

NASA NTRS2019

Nasa Centennial Challenge: Three Dimensional (3d) Printed Habitat, Phase 3

NASA's Centennial Challenges program uses prize competitions with the goal of accelerating innovation in the aerospace industry. Competitions in the Centennial Challenges portfolio have previously focused on advancements in space robotics, regolith excavation, bio-printing, astronaut suit design, small satellites, and solar-powered vehicles. NASA's Three Dimensional (3D) Printed Habitat Centennial Challenge represents a partnership between NASA and the non-profit partner: Bradley University, with co-sponsors Caterpillar, Bechtel, Brick and Mortar Ventures, the American Concrete Institute, and the United States Army Corps of Engineers (USACE) Engineer Research and Development Center (ERDC) to spur development in automated additive construction technologies. The challenge asks teams to design and construct a scaled and simulated Martian habitat using indigenous materials and large scale 3D automated printing systems. Phase 1 of the competition, held in 2015, was an architectural design competition for habitat concepts that could be 3D printed. Phase 2, completed in 2017, asked teams to develop feedstocks from indigenous materials and hydrocarbon polymer recyclables, and demonstrate automated printing systems to manufacture these feedstocks into test specimens to assess mechanical strength. This paper will discuss the Phase 3 competition, focusing on technology outcomes that can potentially be infused into both terrestrial and planetary construction applications. The Phase 3 competition was divided into two sub-competitions: 1) virtual construction, where teams created a high fidelity building information model (BIM) of their 3D-printed habitat design and 2) the construction competition, which required teams to 3D print a structural foundation and subject materials samples to freeze/thaw testing and impact testing (level 1), produce a habitat element and complete a hydrostatic test (level 2), and additively manufacture a 1:3 scale habitat onsite in a head to head competition at Caterpillar, inc.'s Edwards Demonstration & Learning Center near Peoria, Illinois over the course of three days (level 3). While the Phase 2 competition focused primarily on the development of novel feedstocks and robotic printing systems, Phase 3 emphasized the scale-up of these systems and autonomous operation (demonstrating the capability to operate systems on precursor missions prior to the arrival of crew, or terrestrially in field operation settings where human tending of a manufacturing system may be limited). The Phase 3 virtual construction levels yielded a number of novel habitat designs, including both modular habitats and vertically-oriented habitat concepts. The Phase 3 construction competition also challenged teams to autonomously place penetrations and interfacing elements in additively manufactured structures. The paper will emphasize potential applications for the new materials and technologies developed under the umbrella of the competition within NASA's portfolio and in Earth-based applications such as disaster response and infrastructure improvement.

Centennial challenge↗

NASA NTRS2018

Creating a Multifunctional Composite Stator Slot Material System to Enable High Power Density Electric Machines for Electrified Aircraft Applications

Increasing the power density and efficiency of electric machines (motors and generators) is integral to bringing Electrified Aircraft (EA) to commercial realization. However, power density and efficiency are not qualities that can be developed independently. At the heart of any electric machine are the conductors (usually copper) that carry current and generate magnetic fields. Increased power density means increased current density and increased joule heating in a smaller volume. To increase efficiency at the wire level means minimizing electrical resistance and hence power lost to joule heating. There are fundamental challenges with concomitantly increasing both power density and efficiency since the copper resistivity is very temperature sensitive at common electric machine operating conditions. Simple calculations of the linear increase in resistivity of copper as a function of temperature, reveals that a one degree Celsius increase in temperature results in a 0.39% decrease in efficiency. Conversely, a 20 degree Celsius decrease in copper temperature produces a 7.8% increase in efficiency. Therefore, improved thermal management concepts for electric machine building blocks such as stator winding are a priority for improving efficiency and power density. This paper proposing changing the view of component materials in the stator slots from individual components with singular functionality to a composite system where the components take on a multifunctional roles. In the composite framework, achievable material development goals are defined that together have maximum system impact on the thermal environment inside of high power density electric machines for aerospace applications.

thermal management↗

NASA NTRS2018

Composite Bonded Joint: Repair Development

This report documents the details of my work as a NASA KSC intern for the Fall Session from August 27th to December 14th, 2018. My efforts and contributions were with the Materials Science Branch, a staffed organization within the Laboratories, Development, & Testing (NE-L) Division of the Engineering Directorate. The principle responsibilities of the Materials Science group are to support the design, development, and operations activities for materials and processes with the purpose of providing unique solutions for flight hardware, ground support equipment, and customer requests. My role as an intern focused on assisting engineers in developing repair processes to mature bonded joint technology in support of SLS ? scale hardware. My primary goals for this internship were to become more familiar with composite materials and learn more about processes I was unfamiliar with, such as prepregs and out-of-autoclave processing. This project allowed me to learn new skills such as scarfing and curing composites. Additional goals I had were to learn more about NASA's laboratories and projects under development. This internship not only provided me with those experiences, but also allowed me to build relationships with inspiring engineers; a takeaway I will never forget.

Composite Materials↗

NASA NTRS2024

Role of Oxygen Fugacity on the Melting Properties of Enstatite Chondrites and Implications for Mercury’s Magmatic Evolution

Mercury, the innermost terrestrial planet, is the most reduced planet in our solar system. Insights from MESSENGER mission data revealed the presence of several distinct geochemical terranes, evidence of complex magmatic processes and collisional processes exposing subsurface materials. Surface chemical analysis indicated elevated S (~2-3 wt%) and low FeO (~1.5 wt%) concentrations. The high sulfur concentration indicates reduced conditions with an average of 5.4 log units below the Iron-Wüstite (IW) oxygen fugacity ( O 2 ) buffer (IW-5.4). Surface compositions also show a range in redox conditions during mantle melting and eruption, with inferred log f O 2 , ranging from IW-6.5 to IW-3.5. The effects of oxygen fugacity on magmatic differentiation are poorly constrained, despite their significance in our understanding of mantle-crust differentiation in the solar system. Enstatite High-Fe (EH) chondrites are very reduced undifferentiated meteorites with elevated concentrations of Fe and volatiles like S, Cl, Na, and K as compared to other chondrites. These characteristics suggest that EH chondrites are a potential analog for Mercury’s building blocks. However, the comparison of Mercury’s surface composition with melting products of EH chondrites is necessary to determine whether Mercury surface materials may be derived from EH chondrite- like materials. Here, we investigate the role of f O 2 on EH melting properties and its implications for Mercury’s accretion and differentiation.

Mercury↗

NASA NTRS2003

Carbon Nanotube/Conductive Additive/Space Durable Polymer Nanocomposite Films for Electrostatic Charge Dissipation

Thin film membranes of space environmentally stable polymeric materials possessing low color/solar absorptivity (alpha) are of interest for potential applications on Gossamer spacecraft. In addition to these properties, sufficient electrical conductivity is required in order to dissipate electrostatic charge (ESC) build-up brought about by the charged orbital environment. One approach to achieve sufficient electrical conductivity for ESC mitigation is the incorporation of single wall carbon nanotubes (SWNTs). However, when the SWNTs are dispersed throughout the polymer matrix, the nanocomposite films tend to be significantly darker than the pristine material resulting in a higher alpha. The incorporation of conductive additives in combination with a decreased loading level of SWNTs is one approach for improving alpha while retaining conductivity. Taken individually, the low loading level of conductive additives and SWNTs is insufficient in achieving the percolation level necessary for electrical conductivity. When added simultaneously to the film, conductivity is achieved through a synergistic effect. The chemistry, physical, and mechanical properties of the nanocomposite films will be presented.

Smith, Joseph G., Jr.↗

NASA NTRS2007

Recent Advances in Photonic Devices for Optical Computing and the Role of Nonlinear Optics-Part II

The twentieth century has been the era of semiconductor materials and electronic technology while this millennium is expected to be the age of photonic materials and all-optical technology. Optical technology has led to countless optical devices that have become indispensable in our daily lives in storage area networks, parallel processing, optical switches, all-optical data networks, holographic storage devices, and biometric devices at airports. This chapters intends to bring some awareness to the state-of-the-art of optical technologies, which have potential for optical computing and demonstrate the role of nonlinear optics in many of these components. Our intent, in this Chapter, is to present an overview of the current status of optical computing, and a brief evaluation of the recent advances and performance of the following key components necessary to build an optical computing system: all-optical logic gates, adders, optical processors, optical storage, holographic storage, optical interconnects, spatial light modulators and optical materials.

Abdeldayem, Hossin↗

NASA NTRS1980

Space fabrication - The key to future large space systems

Construction techniques for large space structures are discussed. It is pointed out that in contrast to assembly in orbit and the deployment technique space fabrication offers favorable densities (transporting structural materials on reels) and can be adapted to automated construction. A space fabrication machine containing reels of flat sheet material and sets of rollers or dies is described, as is a machine for fabricating composite material (which must be heated for forming and then cooled to achieve structural strength). The use of fabrication machines to build such structures as space platforms, microwave radiometers, and satellite power systems is discussed. The versatility of the machine when operated in conjunction with the Space Shuttle and a set of jigs is illustrated by showing how large square solar panels and large hexagonal structures could be constructed. The need for a flight demonstration of the fabrication machine is stressed.

Savage, M.↗