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All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

NASA LaRC Strain Gage Balance Design Concepts

The NASA Langley Research Center (LaRC) has been designing strain-gage balances for more than fifty years. These balances have been utilized in Langley's wind tunnels, which span over a wide variety of aerodynamic test regimes, as well as other ground based test facilities and in space flight applications. As a result, the designs encompass a large array of sizes, loads, and environmental effects. Currently Langley has more than 300 balances available for its researchers. This paper will focus on the design concepts for internal sting mounted strain-gage balances. However, these techniques can be applied to all force measurement design applications. Strain-gage balance concepts that have been developed over the years including material selection, sting, model interfaces, measuring, sections, fabrication, strain-gaging and calibration will be discussed.

Rhew, Ray D.↗
NASA NTRSDate not supplied

Use of Tardigrade Proteins for Enhancing Cellular Stress Tolerance on the Moon

With sights set on returning a human presence to the Moon and plans to explore even farther beyond, it is imperative we understand the impact of deep space radiation, partial gravity, and the lunar surface on biology. The need for countermeasures to protect future astronauts from the unique conditions of space is ever-pressing and an assessment of bioproduction capabilities in space is a crucial step for sustaining long-term missions. The Lunar Explorer Instrument for space biology Applications (LEIA) aims to investigate the cell’s response to the lunar environment and test strategies for enhancing cellular tolerance on the Moon, utilizing the budding yeast Saccharomyces cerevisiae as a biosensor. S. cerevisiae serves as an excellent model organism due to its widespread use as an analog for human cells, well-characterized set of genetic tools, and ability to survive desiccation. However, these cells must remain desiccated for up to one year prior to launch and the radiation-sensitive strains designed for LEIA will likely be more vulnerable to desiccation effects. In this work, we introduce tardigrade proteins known for their protective mechanisms into potential LEIA strains to test genetic strategies for improving desiccation and radiation tolerance. Tardigrades are extremotolerant animals well-known for their ability to survive in harsh environments. Notably, they can survive extreme desiccation and radiation due to the upregulation of intrinsically disordered proteins (IDPs). It has been shown that integration of these tardigrade IDPs, such as cytosolic abundant heat-soluble (CAHS) proteins, into yeast can confer increased desiccation tolerance in synergy with trehalose. Our ongoing testing and assessment of bioengineered radiation and desiccation tolerance will help us gain insight into optimizing strain design and selection for protecting LEIA’s biological payload as well as genetic engineering strategies for enhancing bioproduction potential for future missions beyond low Earth orbit.

Genetics↗
NASA NTRSDate not supplied

Use of Tardigrade Proteins for Enhancing Cellular Stress Tolerance on the Moon

With sights set on returning a human presence to the Moon and plans to explore even farther beyond, it is imperative we understand the impact of deep space radiation, partial gravity, and the lunar surface on biology. The need for countermeasures to protect future astronauts from the unique conditions of space is ever-pressing and an assessment of bioproduction capabilities in space is a crucial step for sustaining long-term missions. The Lunar Explorer Instrument for space biology Applications (LEIA) aims to investigate the cell’s response to the lunar environment and test strategies for enhancing cellular tolerance on the Moon, utilizing the budding yeast Saccharomyces cerevisiae as a biosensor. S. cerevisiae serves as an excellent model organism due to its widespread use as an analog for human cells, well-characterized set of genetic tools, and ability to survive desiccation. However, these cells must remain desiccated for up to one year prior to launch and the radiation-sensitive strains designed for LEIA will likely be more vulnerable to desiccation effects. In this work, we introduce tardigrade proteins known for their protective mechanisms into potential LEIA strains to test genetic strategies for improving desiccation and radiation tolerance. Tardigrades are extremotolerant animals well-known for their ability to survive in harsh environments. Notably, they can survive extreme desiccation and radiation due to the upregulation of intrinsically disordered proteins (IDPs). It has been shown that integration of these tardigrade IDPs, such as cytosolic abundant heat-soluble (CAHS) proteins, into yeast can confer increased desiccation tolerance in synergy with trehalose. Our ongoing testing and assessment of bioengineered radiation and desiccation tolerance will help us gain insight into optimizing strain design and selection for protecting LEIA’s biological payload as well as genetic engineering strategies for enhancing bioproduction potential for future missions beyond low Earth orbit.

Genetics↗
NASA NTRS2001

Cryogenic Tank Structure Sizing With Structural Optimization Method

Structural optimization methods in MSC /NASTRAN are used to size substructures and to reduce the weight of a composite sandwich cryogenic tank for future launch vehicles. Because the feasible design space of this problem is non-convex, many local minima are found. This non-convex problem is investigated in detail by conducting a series of analyses along a design line connecting two feasible designs. Strain constraint violations occur for some design points along the design line. Since MSC/NASTRAN uses gradient-based optimization procedures. it does not guarantee that the lowest weight design can be found. In this study, a simple procedure is introduced to create a new starting point based on design variable values from previous optimization analyses. Optimization analysis using this new starting point can produce a lower weight design. Detailed inputs for setting up the MSC/NASTRAN optimization analysis and final tank design results are presented in this paper. Approaches for obtaining further weight reductions are also discussed.

Wang, J. T.↗
NASA NTRS2001

Cryogenic Tank Structure Sizing With Structural Optimization Method

Structural optimization methods in MSC/NASTRAN are used to size substructures and to reduce the weight of a composite sandwich cryogenic tank for future launch vehicles. Because the feasible design space of this problem is non-convex, many local minima are found. This non-convex problem is investigated in detail by conducting a series of' analyses along a design line connecting two feasible designs. Strain constraint violations occur for some design points along the design line. Since MSC/NASTRAN uses gradient based optimization procedures, it does not guarantee that the lowest weight design can be found. In this study, a simple procedure is introduced to create a new starting point based on design variable values from previous optimization analyses. Optimization analysis using this new starting point can produce a lower weight design. Detailed inputs for setting up the MSC/NASTRAN optimization analysis and final tank design results are presented in this paper. Approaches for obtaining further weight reductions are also discussed.

Wang, J. T.↗
NASA NTRS2003

High-Frequency Testing of Composite Fan Vanes With Erosion-Resistant Coating Conducted

The mechanical integrity of hard, erosion-resistant coatings were tested using the Structural Dynamics Laboratory at the NASA Glenn Research Center. Under the guidance of Structural Mechanics and Dynamics Branch personnel, fixturing and test procedures were developed at Glenn to simulate engine vibratory conditions on coated polymer-matrix- composite bypass vanes using a slip table in the Structural Dynamics Laboratory. Results from the high-frequency mechanical bench testing, along with concurrent erosion testing of coupons and vanes, provided sufficient confidence to engine-endurance test similarly coated vane segments. The knowledge gained from this program will be applied to the development of oxidation- and erosion-resistant coatings for polymer matrix composite blades and vanes in future advanced turbine engines. Fan bypass vanes from the AE3007 (Rolls Royce America, Indianapolis, IN) gas turbine engine were coated by Engelhard (Windsor, CT) with compliant bond coatings and hard ceramic coatings. The coatings were developed collaboratively by Glenn and Allison Advanced Development Corporation (AADC)/Rolls Royce America through research sponsored by the High-Temperature Engine Materials Technology Project (HITEMP) and the Higher Operating Temperature Propulsion Components (HOTPC) project. High-cycle fatigue was performed through high-frequency vibratory testing on a shaker table. Vane resonant frequency modes were surveyed from 50 to 3000 Hz at input loads from 1g to 55g on both uncoated production vanes and vanes with the erosion-resistant coating. Vanes were instrumented with both lightweight accelerometers and strain gauges to establish resonance, mode shape, and strain amplitudes. Two high-frequency dwell conditions were chosen to excite two strain levels: one approaching the vane's maximum allowable design strain and another near the expected maximum strain during engine operation. Six specimens were tested per dwell condition. Pretest and posttest inspections were performed optically at up to 60 magnification and using a fluorescent-dye penetrant. Accumulation of 10 million cycles at a strain amplitude of two to three times that expected in the engine (approximately 670 Hz and 20g) led to the development of multiple cracks in the coating that were only detectable using fluorescent-dye penetrant inspection. Cracks were prevalent on the trailing edge and on the convex side of the midsection. No cracking or spalling was evident using standard optical inspection at up to 60 magnification. Further inspection may reveal whether these fine cracks penetrated the coating or were strictly on the surface. The dwell condition that simulated actual engine conditions produced no obvious surface flaws even after up to 80 million cycles had been accumulated at strain amplitudes produced at approximately 1500 Hz and 45g.

Bowman, Cheryl L.↗
NASA NTRS2000

Analysis and Test of Repair Concepts for a Carbon-Rod Reinforced Laminate

The use of pultruded carbon-epoxy rods for the reinforcement of composite laminates in some structures results in an efficient structural concept. The results of an analytical and experimental investigation of repair concepts of completely severed carbon-epoxy rods is presented. Three repair concepts are considered: (a) bonded repair with outside moldline and inside moldline doublers; (b) bonded repair with fasteners, and (c) bonded repair with outside moldline doubler only. The stiffness of the repairs was matched with the stiffness of the baseline specimen. The failure strains for the bonded repair with fasteners and the bonded repair with an outside moldline doubler exceeded a target design strain set for the repair concepts.

Baker, Donald J.↗
NASA NTRS1991

Minimum-weight design of laminated composite plates for postbuckling performance

Minimum-weight design of simply-supported, symmetrically laminated, thin, rectangular, specially orthotropic laminated plates for buckling and postbuckling strength is investigated. The postbuckling analysis is based on an Marguerre-type energy method. The failure load of laminates is calculated by the maximum strain failure criterion based on the in-plane strains. Design variables are individual layer thicknesses with specified fiber orientations. Optimization with discrete valued design is achieved by introducing additional penalty terms to the regular pseudoobjective function of sequential unconstrained minimization technique. The proposed optimization technique is applied to the design of rectangular laminates with various aspect ratios loaded by axial compressive loads.

Shin, Dong KU↗
NASA NTRS1999

Haloanaerobium kushneri sp. nov., an obligately halophilic, anaerobic bacterium from an oil brine

Three strains, designated VS-751T, VS-511 and VS-732, of a strictly anaerobic, moderately halophilic, Gram-negative, rod-shaped bacterium were isolated from a highly saline (15-20%) brine from an oil reservoir in central Oklahoma, USA. The optimal concentration of NaCl for growth of these three strains was 2 M (12%), and the strains also grew in the presence of an additional 1 M MgCl2. The strains were mesophilic and grew at a pH range of 6-8. Carbohydrates used by all three strains included glucose, fructose, arabinose, galactose, maltose, mannose, cellobiose, sucrose and inulin. Glucose fermentation products included ethanol, acetate, H2 and CO2, with formate produced by two of the three strains. Differences were noted among strains in the optimal temperature and pH for growth, the maximum and minimum NaCl concentration that supported growth, substrate utilization and cellular fatty acid composition. Despite the phenotypic differences among the three strains, analysis of the 16S rRNA gene sequences and DNA-DNA hybridizations showed that these three strains were members of the same genospecies which belonged to the genus Haloanaerobium. The phenotypic and genotypic characteristics of strains VS-751T, VS-511 and VS-732 are different from those of previously described species of Haloanaerobium. It is proposed that strain VS-751T (ATCC 700103T) be established as the type strain of a new species, Haloanaerobium kushneri.

NASA Discipline Exobiology↗
NASA NTRS2000

Rhodoferax antarcticus sp. nov., a moderately psychrophilic purple nonsulfur bacterium isolated from an Antarctic microbial mat

A new species of purple nonsulfur bacteria isolated from an Antarctic microbial mat is described. The organism, designated strain ANT.BR, was mildly psychrophilic, growing optimally at 15-18 degrees C with a growth temperature range of 0-25 degrees C. Cells of strain ANT.BR were highly motile curved rods and spirals, contained bacteriochlorophyll a, and showed a multicomponent in vivo absorption spectrum. A specific phylogenetic relationship was observed between strain ANT.BR and the purple bacterium Rhodoferax fermentans FR2T, and the two organisms shared several physiological and other phenotypic properties, with the notable exception of growth temperature optimum. Tests of genomic DNA hybridization, however, showed Rfx. fermentans FR2T and strain ANT.BR to be genetically distinct bacteria. Because of its unique set of properties, especially its requirement for low growth temperatures, we propose to recognize strain ANT.BR as a new species of the genus Rhodoferax, Rhodoferax antarcticus, named for its known habitat, the Antarctic.

NASA Discipline Exobiology↗
NASA NTRS1992

Advanced wing design survivability testing and results

Composite wings on current operational aircraft are conservatively designed to account for stress/strain concentrations, and to assure specified damage tolerance. The technology that can lead to improved composite wing structures and associated structural efficiency is to increase design ultimate strain levels beyond their current limit of 3500 to 4000 micro-in/in to 6000 micro-in/in without sacrificing structural integrity, durability, damage tolerance, or survivability. Grumman, under the sponsorship of the Naval Air Development Center (NADC), has developed a high-strain composite wing design for a subsonic aircraft wing using novel and innovative design concepts and manufacturing methods, while maintaining a state-of-the-art fiber/resin system. The current advanced wing design effort addressed a tactical subsonic aircraft wing using previously developed, high-strain wing design concepts in conjunction with newer/emerging fiber and polymer matrix composite (PMC) materials to achieve the same goals, while reducing complexity. Two categories of advanced PMC materials were evaluated: toughened thermosets; and engineered thermoplastics. Advanced PMC materials offer the technological opportunity to take maximum advantage of improved material properties, physical characteristics, and tailorability to increase performance and survivability over current composite structure. Damage tolerance and survivability to various threats, in addition to structural integrity and durability, were key technical issues addressed during this study, and evaluated through test. This paper focuses on the live-fire testing, and the results performed to experimentally evaluate the survivability of the advanced wing design.

Bruno, J.↗
NASA NTRS1993

Test results from large wing and fuselage panels

This paper presents the first results in an assessment of the strength, stiffness, and damage tolerance of stiffened wing and fuselage subcomponents. Under this NASA funded program, 10 large wing and fuselage panels, variously fabricated by automated tow placement and dry-stitched preform/resin transfer molding, are to be tested. The first test of an automated tow placement six-longeron fuselage panel under shear load was completed successfully. Using NASTRAN finite-element analysis the stiffness of the panel in the linear range prior to buckling was predicted within 3.5 percent. A nonlinear analysis predicted the buckling load within 10 percent and final failure load within 6 percent. The first test of a resin transfer molding six-stringer wing panel under compression was also completed. The panel failed unexpectedly in buckling because of inadequate supporting structure. The average strain was 0.43 percent with a line load of 20.3 kips per inch of width. This strain still exceeds the design allowable strains. Also, the stringers did not debond before failure, which is in contrast to the general behavior of unstitched panels.

Madan, Ram C.↗
NASA NTRS2022

Discovery of Chlorophyll d : Isolation and Characterization of a Far-Red Cyanobacterium from the Original Site of Manning and Strain (1943) at Moss Beach, California

We have isolated a chlorophyll-d-containing cyanobacterium from the intertidal field site at Moss Beach, on the coast of Central California, USA, where Manning and Strain (1943) originally discovered this far-red chlorophyll. Here, we present the cyanobacterium’s environmental description, culturing procedure, pigment composition, ultrastructure, and full genome sequence. Among cultures of far-red cyanobacteria obtained from red algae from the same site, this strain was an epiphyte on a brown macroalgae. Its Q y in vivo absorbance peak is centered at 704–705 nm, the shortest wavelength observed thus far among the various known Acaryochloris strains. Its Chl a /Chl d ratio was 0.01, with Chl d accounting for 99% of the total Chl d and Chl a mass. TEM imagery indicates the absence of phycobilisomes, corroborated by both pigment spectra and genome analysis. The Moss Beach strain codes for only a single set of genes for producing allophycocyanin. Genomic sequencing yielded a 7.25 Mbp circular chromosome and 10 circular plasmids ranging from 16 kbp to 394 kbp. We have determined that this strain shares high similarity with strain S15, an epiphyte of red algae, while its distinct gene complement and ecological niche suggest that this strain could be the closest known relative to the original Chl d source of Manning and Strain (1943). The Moss Beach strain is designated Acaryochloris sp. (marina) strain Moss Beach.

chlorophyll d↗
NASA NTRS1996

Novel Composites for Wing and Fuselage Applications: Novel Wing Design Concepts - Task 1

Design trade studies were conducted to arrive at advanced wing designs that integrated new material forms with innovative structural concepts and cost-effective fabrication methods. A representative spar was selected for design, fabrication, and test to validate the predicted performance. Textile processes, such as knitting, weaving and stitching, were used to produce fiber preforms that were later fabricated into composite span through epoxy Resin Transfer Molding (RTM), Resin Film Infusion (RFI), and consolidation of commingled thermoplastic and graphite tows. The target design ultimate strain level for these innovative structural design concepts was 6000 mu in. per in. The spars were subjected to four-point beam bending to validate their structural performance. The various material form /processing combination Y-spars were rated for their structural efficiency and acquisition cost. The acquisition cost elements were material, tooling, and labor.

Suarez, J. A.↗
NASA NTRS1969

Design of a strain-gage probe

Strain-gage spacer probe uses the deflection of a leaf spring to measure strain in a long, slender beam nondestructively. The selected gage is of the smallest practical size, as thin as possible and yet of a standard type.

Kolba, V. M.↗
NASA NTRS1999

First International Symposium on Strain Gauge Balances

The first International Symposium on Strain Gauge Balances was sponsored and held at NASA Langley Research Center during October 22-25, 1996. The symposium provided an open international forum for presentation, discussion, and exchange of technical information among wind tunnel test technique specialists and strain gauge balance designers. The Symposium also served to initiate organized professional activities among the participating and relevant international technical communities. Over 130 delegates from 15 countries were in attendance. The program opened with a panel discussion, followed by technical paper sessions, and guided tours of the National Transonic Facility (NTF) wind tunnel, a local commercial balance fabrication facility, and the LaRC balance calibration laboratory. The opening panel discussion addressed "Future Trends in Balance Development and Applications." Forty-six technical papers were presented in 11 technical sessions covering the following areas: calibration, automatic calibration, data reduction, facility reports, design, accuracy and uncertainty analysis, strain gauges, instrumentation, balance design, thermal effects, finite element analysis, applications, and special balances. At the conclusion of the Symposium, a steering committee representing most of the nations and several U.S. organizations attending the Symposium was established to initiate planning for a second international balance symposium, to be held in 1999 in the UK.

John S Tripp↗