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At least 1,387 records · Page 77

Interactive computer aided technology, evolution in the design/manufacturing process

A powerful computer-operated three dimensional graphic system and associated auxiliary computer equipment used in advanced design, production design, and manufacturing was described. This system has made these activities more productive than when using older and more conventional methods to design and build aerospace vehicles. With the use of this graphic system, designers are now able to define parts using a wide variety of geometric entities, define parts as fully surface 3-dimensional models as well as "wire-frame" models. Once geometrically defined, the designer is able to take section cuts of the surfaced model and automatically determine all of the section properties of the planar cut, lightpen detect all of the surface patches and automatically determine the volume and weight of the part. Further, his designs are defined mathematically at a degree of accuracy never before achievable.

English, C. H.↗

Product definition data interface

The development and application of advanced Computer Aided Design/Computer Aided Manufacturing (CAD/CAM) technology in aerospace industry is discussed. New CAD/CAM capabilities provide the engineer and production worker with tools to produce better products and significantly improve productivity. This technology is expanding in all phases of engineering and manufacturing with large potential for improvements in productivity. The integration of CAD and CAM systematically to insure maximum utility throughout the U.S. Aerospace Industry, its large community of supporting suppliers, and the Department of Defense aircraft overhaul and repair facilities is outlined. The need for a framework for exchange of digital product definition data, which serves the function of the conventional engineering drawing is emphasized.

Birchfield, B.↗

Temperature effect on stress concentration around circular hole in a composite material specimen representative of X-29A forward-swept wing aircraft

The theory of anisotropic elasticity was used to evaluate the anisotropic stress concentration factors of a composite laminated plate containing a small circular hole. This advanced composite was used to manufacture the X-29A forward-swept wing. It was found for composite material, that the anisotropic stress concentration is no longer a constant, and that the locations of maximum tangential stress points could shift by changing the fiber orientation with respect to the loading axis. The analysis showed that through the lamination process, the stress concentration factor could be reduced drastically, and therefore the structural performance could be improved. Both the mixture rule approach and the constant strain approach were used to calculate the stress concentration factor of room temperature. The results predicted by the mixture rule approach were about twenty percent deviate from the experimental data. However, the results predicted by the constant strain approach matched the testing data very well. This showed the importance of the inplane shear effect on the evaluation of the stress concentration factor for the X-29A composite plate.

Yeh, Hsien-Yang↗

Performance analysis of Integrated Communication and Control System networks

This paper presents statistical analysis of delays in Integrated Communication and Control System (ICCS) networks that are based on asynchronous time-division multiplexing. The models are obtained in closed form for analyzing control systems with randomly varying delays. The results of this research are applicable to ICCS design for complex dynamical processes like advanced aircraft and spacecraft, autonomous manufacturing plants, and chemical and processing plants.

Halevi, Y.↗

Overall goals

Space transportation propulsion systems symposium is discussed. The following subject areas are covered: overall goals; main issues; materials characterization; reduction of manufacturing defects; standards and certification; advanced NDE techniques; designing for inspectability; candidate programs/milestones; and NDE technology potentials.

Baaklini, George↗

Space propulsion

Lewis Research Center is developing broad-based new technologies for space chemical engines to satisfy long-term needs of ETO launch vehicles and other vehicles operating in and beyond Earth orbit. Specific objectives are focused on high performance LO2/LH2 engines providing moderate thrusts of 7,5-200 klb. This effort encompasses research related to design analysis and manufacturing processes needed to apply advanced materials to subcomponents, components, and subsystems of space-based systems and related ground-support equipment. High-performance space-based chemical engines face a number of technical challenges. Liquid hydrogen turbopump impellers are often so large that they cannot be machined from a single piece, yet high stress at the vane/shroud interface makes bonding extremely difficult. Tolerances on fillets are critical on large impellers. Advanced materials and fabricating techniques are needed to address these and other issues of interest. Turbopump bearings are needed which can provide reliable, long life operation at high speed and high load with low friction losses. Hydrostatic bearings provide good performance, but transients during pump starts and stops may be an issue because no pressurized fluid is available unless a separate bearing pressurization system is included. Durable materials and/or coatings are needed that can demonstrate low wear in the harsh LO2/LH2 environment. Advanced materials are also needed to improve the lifetime, reliability and performance of other propulsion system elements such as seals and chambers.

Kazaroff, John M.↗

Current Radiation Issues for Programmable Elements and Devices

State of the an programmable devices are utilizing advanced processing technologies, non-standard circuit structures, and unique electrical elements in commercial-off-the-shelf (COTS)-based, high-performance devices. This paper will discuss that the above factors, coupled with the systems application environment, have a strong interplay that affect the radiation hardness of programmable devices and have resultant system impacts in (1) reliability of the unprogrammed, biased antifuse for heavy ions (rupture), (2) logic upset manifesting itself as clock upset, and (3) configuration upset. General radiation characteristics of advanced technologies are examined and manufacturers' modifications to their COTS-based and their impact on future programmable devices will be analyzed.

Katz, R.↗

Next Generation Space Telescope Ultra-Lightweight Mirror Program

The Next Generation Space Telescope is currently envisioned as a eight meter diameter cryogenic deployable telescope that will operate at the earth sun libration point L2. A number of different designs are being examined within NASA and under industry studies by Ball Aerospace, Lockheed-Martin and TRW. Although these designs differ in many respects, they all require significant advancements in the state-of-the-art with respect to large diameter, ultra-lightweight, mirrors. The purpose of this paper is to provide insight into the current status of the mirror development program NGST is a tremendously ambitious undertaking that sets the mark for new NASA missions. In order to achieve the weight, cost and performance requirements of NGST, the primary mirror must be made lighter, cheaper and better than anything that has ever been done. In order to accomplish this an aggressive technology program has been put in place. The scope of the program was determined by examining historically what has been accomplished; assessing recent technological advances in fabrication and testing; and evaluating the effect of these advances relative to enabling the manufacture of lightweight mirrors that meet NGST requirements. As it is currently envisioned, the primary mirror for NGST is on the order of eight meters in diameter, it is to be diffraction limited at a wave length of 2 microns and has an overall weight requirement of 15 kilograms per square meter. Two large scale demonstration projects are under way along with a number of smaller scale demonstrations on a variety of mirror materials and concepts. The University of Arizona (UA) mirror concept is based around a 2mm thick Borosilicate glass face sheet mounted to a composite backplane structure via actuators for mirror figure correction. The Composite Optics Inc.(COI) concept consists of a 3.2mm thick Zerodur face sheet bonded to a composite support structure which in turn is mounted to a composite backplane structure via actuators for mirror phasing. These mirrors are due to be performance tested in ambient conditions in the fall of '98, and cryogenically tested in the spring of '99. The smaller scale efforts include the following: Beryllium is being investigated at Ball Aerospace, Electroform nickel is being investigated in-house at MSFC, Chemical Vapor Deposition (CVD) Silicon Carbide (SiC) is being investigated at Morton International Silicon mirrors are being investigated at Schafer, Carbon Fiber Reinforced Silicon Carbide (CSIC) is being investigated at IABG. SiC at SSG, Composite mirrors at COI, pyrolyzed graphite mirrors at Ultramet, reaction bonded SiC mirrors at Xinetics, along with techniques for lightweighting using waterjets at Waterjet Technology Inc. are all being investigated under the Small Business innovative Research Program SBIR program. A procurement for a third large scale demonstration (nominally 1.5m in diameter) is being planned for release this fall.

Bilbro, James W.↗

Spinoff 2002: Fortieth Anniversary Technology Utilization Program

Since its inception 40 years ago, NASA's Technology Transfer Program has led the way for our nation to benefit from cutting-edge aerospace technologies. In addition to contributing to U.S. economic growth, these technologies are improving the quality of life on Earth while finding new ways to protect and preserve it. NASA's research and development efforts have advanced areas in medicine, communications, manufacturing, computer technology, and homeland security. These breakthroughs, translated into commercial products, are enhancing the lives of Americans everywhere. When a congressional mandate led NASA to develop the Scientific and Technical Information (STI) Program, the Agency began a wide dissemination of its research and development results. In doing so, NASA recognized that many of its technologies were transferable to industry for the development of commercial products. As a result, the Technology Utilization Program was born in 1962. The successful program went through several changes over the years, as its philosophy, mission, and goals adapted into the Technology Transfer Program we know today. The program strives to make the latest technologies available to industry as soon as they are developed. Each year, NASA's Spinoff publication showcases new products and services resulting from commercial partnerships between NASA and private industry. In the 2002 issue, the NASA field centers reflect upon the growth that has made these innovations available to the public. The Research and Development section examines past achievements, current successes, and future goals for each of the ten NASA centers. The Commercial Benefits section proudly highlights 51 new spinoff products, including a heart pump for patients needing a heart transplant, as well as an air purifier that destroys anthrax spores. The Technology Transfer and Outreach section describes the outreach achievements and educational successes made possible through the NASA Commercial Technology Network. Each section of Spinoff 2002 provides compelling evidence of the Technology Transfer Program's success and value. With commercial products and successes spanning from work on the Apollo missions to the International Space Station, the 40th anniversary of the Technology Transfer Program invites us to celebrate our history while planning the future.

Source record↗

Space Commercialization

A robust and competitive commercial space sector is vital to continued progress in space. The United States is committed to encouraging and facilitating the growth of a U.S. commercial space sector that supports U.S. needs, is globally competitive, and advances U.S. leadership in the generation of new markets and innovation-driven entrepreneurship. Energize competitive domestic industries to participate in global markets and advance the development of: satellite manufacturing; satellite-based services; space launch; terrestrial applications; and increased entrepreneurship. Purchase and use commercial space capabilities and services to the maximum practical extent Actively explore the use of inventive, nontraditional arrangements for acquiring commercial space goods and services to meet United States Government requirements, including measures such as public-private partnerships, . Refrain from conducting United States Government space activities that preclude, discourage, or compete with U.S. commercial space activities. Pursue potential opportunities for transferring routine, operational space functions to the commercial space sector where beneficial and cost-effective.

Martin, Gary L.↗

Advanced Ablative Insulators and Methods of Making Them

Advanced ablative (more specifically, charring) materials that provide temporary protection against high temperatures, and advanced methods of designing and manufacturing insulators based on these materials, are undergoing development. These materials and methods were conceived in an effort to replace the traditional thermal-protection systems (TPSs) of re-entry spacecraft with robust, lightweight, better-performing TPSs that can be designed and manufactured more rapidly and at lower cost. These materials and methods could also be used to make improved TPSs for general aerospace, military, and industrial applications.

Congdon, William M.↗

Thermomechanical Property Prediction of Amorphous and Crystal PEKK via Molecular Dynamics

Traditionally, advanced aerospace composites have been manufactured using thermoset resins. However, recently, thermoplastics have been investigated for use in the manufacturing of composite materials due to their unique manufacturing characteristics. Thermoplastic resins can be reshaped and formed, along with the added benefit of being recyclable, which thermoset resin cannot. Thermoplastic materials undergo a crystallization process during manufacturing which affects the percent crystallinity of the material. The crystallization needs to be understood better to maximize the potential of thermoplastic resins. PEKK is a thermoplastic material with good chemical, thermal, and mechanical loading resistance. PEKK is also a material NASA is interested in for developing new bonded joint technology. The crystalline microstructure of PEKK is at the micrometer length scale, and it is of interest to model the effects of the crystallinity structure on PEKK’s bulk properties. Molecular dynamics (MD) is a simulation tool that allows for property-structure relationships between atomistic structure and nanometer-length portions of a material. This makes MD a useful tool for developing the structure-property relationship of PEKK. However, the micrometer length scale of PEKK’s crystal structure is too large for MD. Thus, a hybrid approach to modeling PEKK’s microstructure is proposed in this work where MD models are built of both the amorphous and crystalline phases of PEKK. The engineering material properties can be obtained using MD at the nanometer length scale. A micromechanics approach can then generate the micrometer length scale of the crystallinity and the effective properties can be homogenized. The objective of this paper is to show the MD model workflow and the MD-predicted properties of PEKK. The properties can then be homogenized with different crystalline percentages to build design graphs that can be used to tailor PEKK for specific composite applications.

poly ether ketone ketone↗

Space Based Solar Power

Space based solar power (SBSP) entails in-space collection of solar energy, transmission of that energy to one or more stations on Earth, conversion to electricity, and delivery to the grid or to batteries for storage. Experts in both the aerospace and energy sectors are debating the benefits of SBSP as more organizations globally begin SBSP technology development programs. We conducted a study to evaluate the potential benefits, challenges, and options for NASA to engage with growing global interest in SBSP. We performed a first order lifecycle study of two representative SBSP designs for 2 GW utility-scale power generation that, for the purposes of the study, are presumed to begin in 2050. We assumed baseline capabilities to develop, assemble, operate, maintain, and dispose of the SBSP systems are a mix of capabilities that are above, below, or comparable to capabilities demonstrated to date. We then compared the lifecycle cost of electricity and lifecycle GHG emission intensity of the SBSP designs to alternative terrestrial renewable electricity production technologies. Our findings indicate the SBSP designs may produce lifecycle GHG emissions per unit of electricity that are comparable to terrestrial alternatives, pending further studies of upper atmosphere responses to launch emissions. We find the SBSP designs are more expensive than terrestrial alternatives and may have lifecycle costs per unit of electricity that are 12-80 times higher. Though, we do find cost competitiveness may be achieved if a favorable combination of cost and capability improvements related to launch and manufacturing that are beyond the advancements assumed in the baseline assessment can be attained.

Erica Rodgers↗

Space Based Solar Power Study

Space based solar power (SBSP) entails in-space collection of solar energy, transmission of that energy to one or more stations on Earth, conversion to electricity, and delivery to the grid or to batteries for storage. Experts in both the aerospace and energy sectors are debating the benefits of SBSP as more organizations globally begin SBSP technology development programs. We conducted a study to evaluate the potential benefits, challenges, and options for NASA to engage with growing global interest in SBSP. We performed a first order lifecycle study of two representative SBSP designs for 2 GW utility-scale power generation that, for the purposes of the study, are presumed to begin in 2050. We assumed baseline capabilities to develop, assemble, operate, maintain, and dispose of the SBSP systems are a mix of capabilities that are above, below, or comparable to capabilities demonstrated to date. We then compared the lifecycle cost of electricity and lifecycle GHG emission intensity of the SBSP designs to alternative terrestrial renewable electricity production technologies. Our findings indicate the SBSP designs may produce lifecycle GHG emissions per unit of electricity that are comparable to terrestrial alternatives, pending further studies of upper atmosphere responses to launch emissions. We find the SBSP designs are more expensive than terrestrial alternatives and may have lifecycle costs per unit of electricity that are 12-80 times higher. Though, we do find cost competitiveness may be achieved if a favorable combination of cost and capability improvements related to launch and manufacturing that are beyond the advancements assumed in the baseline assessment can be attained.

solar↗

Vacuum mechatronics

The discipline of vacuum mechatronics is defined as the design and development of vacuum-compatible computer-controlled mechanisms for manipulating, sensing and testing in a vacuum environment. The importance of vacuum mechatronics is growing with an increased application of vacuum in space studies and in manufacturing for material processing, medicine, microelectronics, emission studies, lyophylisation, freeze drying and packaging. The quickly developing field of vacuum mechatronics will also be the driving force for the realization of an advanced era of totally enclosed clean manufacturing cells. High technology manufacturing has increasingly demanding requirements for precision manipulation, in situ process monitoring and contamination-free environments. To remove the contamination problems associated with human workers, the tendency in many manufacturing processes is to move towards total automation. This will become a requirement in the near future for e.g., microelectronics manufacturing. Automation in ultra-clean manufacturing environments is evolving into the concept of self-contained and fully enclosed manufacturing. A Self Contained Automated Robotic Factory (SCARF) is being developed as a flexible research facility for totally enclosed manufacturing. The construction and successful operation of a SCARF will provide a novel, flexible, self-contained, clean, vacuum manufacturing environment. SCARF also requires very high reliability and intelligent control. The trends in vacuum mechatronics and some of the key research issues are reviewed.

Hackwood, Susan↗

Assessing Manufacturability of the Oxide Dispersion Strengthened (ODS) 14YWT Alloy Fuel Cladding Tube Using SolidStir™ Technology

The 14YWT (Fe–14Cr–3W–0.4Ti–0.3Y2O3 (wt.%)) alloy is a potential candidatematerial for fabricating fuel cladding tubes and other structural components to be used in next-generation advanced nuclear reactors. Due to inherent limitations of current processing routes, this research explored a new variant of friction stir processing, commercially referred to as SolidStir™ Extrusion (patent pending) technology from Enabled Engineering to consolidate and extrude 14YWT powder into a fuel cladding tube. Several single-layer and multiple-layer consolidation experiments were carried out in an Inconel 625 die to determine the suitable processing parameters for SolidStir™ extrusion of the 14YWT alloy cladding tube. With these processing parameters, a 16–18 mm long tube of the 14YWT alloy with no visible defects was successfully extruded using this novel technology. Microstructural characterization results obtained using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, electron backscatter diffraction, and transmission electron microscopy will be presented.

Advanced Materials and Manufacturing Technology↗

Composite transport wing technology development: Design development tests and advanced structural concepts

Numerous design concepts, materials, and manufacturing methods were investigated for the covers and spars of a transport box wing. Cover panels and spar segments were fabricated and tested to verify the structural integrity of design concepts and fabrication techniques. Compression tests on stiffened panels demonstrated the ability of graphite/epoxy wing upper cover designs to achieve a 35 percent weight savings compared to the aluminum baseline. The impact damage tolerance of the designs and materials used for these panels limits the allowable compression strain and therefore the maximum achievable weight savings. Bending and shear tests on various spar designs verified an average weight savings of 37 percent compared to the aluminum baseline. Impact damage to spar webs did not significantly degrade structural performance. Predictions of spar web shear instability correlated well with measured performance. The structural integrity of spars manufactured by filament winding equalled or exceeded those fabricated by hand lay-up. The information obtained will be applied to the design, fabrication, and test of a full-scale section of a wing box. When completed, the tests on the technology integration box beam will demonstrate the structural integrity of an advanced composite wing design which is 25 percent lighter than the metal baseline.

Griffin, Charles F.↗