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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Analysis of Igniter/Promoter Material Effects on Burn Length Variability in Astm G124 Standard Testing

ASTM G124 refers to the “Standard Test Method for Determining the Combustion Behavior of Metallic Materials in Oxygen Enriched Atmospheres”. Major test parameters are well defined in the standard and a detailed description of how to set up and conduct the test is also included. However, one variable - the igniter/promoter system - is not clearly restricted or specified. Due to the fact that this igniter/promoter system is not definitively specified, multiple materials have been used. This lack of specificity in igniter/promoter material was identified as a potential source of variability in test results, and as such has been selected for this study as a parameter to analyze and identify if the igniters/promoters should be standardized. For that purpose, several igniter/promoter systems have been selected (that were currently in use at various laboratories) which would be tested via ASTM G124 with Inconel 718 test rods. Testing was conducted over two phases – the first for screening promoter effects in the transition region of the material, and the second for comparing measured flammability thresholds identified through testing by each igniter/promoter type. The results of this study have found that igniter/promoter material is not a statistically significant factor in the variability of burn length in test samples. Initial results showing variability was likely due to small sample size, as the issue became less pronounced once more samples were tested and more data generated. Each of the igniter/promoter systems tested were effective at determining flammability thresholds and so it is concluded that no specific igniter/promoter needs to be identified in the ASTM G124 test standard.

oxygen compatibility↗
NASA NTRS1994

ASTM E 1559 method for measuring material outgassing/deposition kinetics has applications to aerospace, electronics, and semiconductor industries

The American Society for Testing and Materials has published a new standard test method for characterizing time and temperature-dependence of material outgassing kinetics and the deposition kinetics of outgassed species on surfaces at various temperatures. This new ASTM standard, E 1559(1), uses the quartz crystal microbalance (QCM) collection measurement approach. The test method was originally developed under a program sponsored by the United States Air Force Materials Laboratory (AFML) to create a standard test method for obtaining outgassing and deposition kinetics data for spacecraft materials. Standardization by ASTM recognizes that the method has applications beyond aerospace. In particular, the method will provide data of use to the electronics, semiconductor, and high vacuum industries. In ASTM E 1559 the material sample is held in vacuum in a temperature-controlled effusion cell, while its outgassing flux impinges on several QCM's which view the orifice of the effusion cell. Sample isothermal total mass loss (TML) is measured as a function of time from the mass collected on one of the QCM's which is cooled by liquid nitrogen, and the view factor from this QCM to the cell. The amount of outgassed volatile condensable material (VCM) on surfaces at higher temperatures is measured as a function of time during the isothermal outgassing test by controlling the temperatures of the remaining QCM's to selected values. The VCM on surfaces at temperatures in between those of the collector QCM's is determined at the end of the isothermal test by heating the QCM's at a controlled rate and measuring the mass loss from the end of the QCM's as a function of time and temperature. This reevaporation of the deposit collected on the QCM's is referred to as QCM thermogravimetric analysis. Isothermal outgassing and deposition rates can be determined by differentiating the isothermal TML and VCM data, respectively, while the evaporation rates of the species can be obtained as a function of temperature by differentiating the QCM thermogravimetric analysis data.

Garrett, J. W.↗
NASA NTRS2020

Leveraging ASTM Industry Standard F3269-17 for Providing Safe Operations of a Highly Autonomous Aircraft

This paper expands upon the ASTM industry standard F3269-17 to outline a run-time assurance (RTA) network architecture for use in ensuring safe flight operations of a highly autonomous aircraft. An RTA network architecture is proposed and critical features discussed to implement functions where automation is primarily responsible for the safety of the aircraft instead of a pilot. This shift in responsibility, made possible by the proposed architecture, is key to highly resilient automation and is a core enabler for future “pilotless” transportation concepts. The findings in this paper stem from the researcher’s experiences with ASTM in the generation of the standard and some seven years of RTA system development on various flight programs leveraging the RTA concepts outlined in the ASTM standard.

autonomous systems↗
NASA NTRS1973

Comparison of combustion characteristics of ASTM A-1, propane, and natural-gas fuels in an annular turbojet combustor

The performance of an annular turbojet combustor using natural-gas fuel is compared with that obtained using ASTM A-1 and propane fuels. Propane gas was used to simulate operation with vaporized kerosene fuels. The results obtained at severe operating conditions and altitude relight conditions show that natural gas is inferior to both ASTM A-1 and propane fuels. Combustion efficiencies were significantly lower and combustor pressures for relight were higher with natural-gas fuel than with the other fuels. The inferior performance of natural gas is shown to be caused by the chemical stability of the methane molecule.

Wear, J. D.↗
NASA NTRS1973

Effect of primary-zone water injection on pollutants from a combustor burning liquid ASTM A-1 and vaporized propane fuels

A combustor segment 0.457 meter (18 in.) long with a maximum cross section of 0.153 by 0.305 meter (6 by 12 in.) was operated at inlet-air temperatures of 590 and 700 K, inlet-air pressures of 4 and 10 atmospheres, and fuel-air ratios of 0.014 and 0.018 to determine the effect of primary-zone water injection on pollutants from burning either propane or ASTM A-1 fuel. At a simulated takeoff condition of 10 atmospheres and 700 K, multiple-orifice nozzles used to inject water at 1 percent of the airflow rate reduced nitrogen oxides 75 percent with propane and 65 percent with ASTM A-1 fuel. Although carbon monoxide and unburned hydrocarbons increased with water injection, they remained relatively low; and smoke numbers were well below the visibility limit.

Ingebo, R. D.↗
NASA NTRS1986

Comparative results of autogenous ignition temperature measurements by ASTM G 72 and pressurized scanning calorimetry in gaseous oxygen

The autogenous ignition temperature of four materials was determined by ASTM (G 72) and pressurized differential scanning calorimetry at 0.68-, 3.4-, and 6.8-MPa oxygen pressure. All four materials were found to ignite at lower temperatures in the ASTM method. The four materials evaluated in this program were Neoprene, Vespel SP-21, Fluorel E-2160, and nylon 6/6.

Bryan, C. J.↗
NASA NTRS1992

Results of ASTM round robin testing for mode 1 interlaminar fracture toughness of composite materials

The results are summarized of several interlaboratory 'round robin' test programs for measuring the mode 1 interlaminar fracture toughness of advanced fiber reinforced composite materials. Double Cantilever Beam (DCB) tests were conducted by participants in ASTM committee D30 on High Modulus Fibers and their Composites and by representatives of the European Group on Fracture (EGF) and the Japanese Industrial Standards Group (JIS). DCB tests were performed on three AS4 carbon fiber reinforced composite materials: AS4/3501-6 with a brittle epoxy matrix; AS4/BP907 with a tough epoxy matrix; and AS4/PEEK with a tough thermoplastic matrix. Difficulties encountered in manufacturing panels, as well as conducting the tests are discussed. Critical issues that developed during the course of the testing are highlighted. Results of the round robin testing used to determine the precision of the ASTM DCB test standard are summarized.

Obrien, T. Kevin↗
NASA NTRS1992

The breaking load method - Results and statistical modification from the ASTM interlaboratory test program

The breaking load test provides quantitative stress corrosion cracking data by determining the residual strength of tension specimens that have been exposed to corrosive environments. Eight laboratories have participated in a cooperative test program under the auspices of ASTM Committee G-1 to evaluate the new test method. All eight laboratories were able to distinguish between three tempers of aluminum alloy 7075. The statistical analysis procedures that were used in the test program do not work well in all situations. An alternative procedure using Box-Cox transformations shows a great deal of promise. An ASTM standard method has been drafted which incorporates the Box-Cox procedure.

Colvin, E. L.↗
NASA NTRS2009

Verification of the ASTM G-124 Purge Equation

ASTM G-124 seeks to evaluate combustion characteristics of metals in high-purity (greater than 99%) oxygen atmospheres. ASTM G-124 provides the following equation to determine the minimum number of purges required to reach this level of purity in a test chamber: n = -4/log10(Pa/Ph), where "n" is the total number of purge cycles required, Ph is the absolute pressure used for the purge on each cycle and Pa is the atmospheric pressure or the vent pressure. The origin of this equation is not known and has been the source of frequent questions as to its accuracy and reliability. This paper shows the derivation of the G-124 purge equation, and experimentally explores the equation to determine if it accurately predicts the number of cycles required.

Robbins, Katherine E.↗
NASA NTRS2016

Improved ASTM G72 Test Method for Ensuring Adequate Fuel-to-Oxidizer Ratios

The ASTM G72/G72M-15 Standard Test Method for Autogenous Ignition Temperature of Liquids and Solids in a High-Pressure Oxygen-Enriched Environment is currently used to evaluate materials for the ignition susceptibility driven by exposure to external heat in an enriched oxygen environment. Testing performed on highly volatile liquids such as cleaning solvents has proven problematic due to inconsistent test results (non-ignitions). Non-ignition results can be misinterpreted as favorable oxygen compatibility, although they are more likely associated with inadequate fuel-to-oxidizer ratios. Forced evaporation during purging and inadequate sample size were identified as two potential causes for inadequate available sample material during testing. In an effort to maintain adequate fuel-to-oxidizer ratios within the reaction vessel during test, several parameters were considered, including sample size, pretest sample chilling, pretest purging, and test pressure. Tests on a variety of solvents exhibiting a range of volatilities are presented in this paper. A proposed improvement to the standard test protocol as a result of this evaluation is also presented. Execution of the final proposed improved test protocol outlines an incremental step method of determining optimal conditions using increased sample sizes while considering test system safety limits. The proposed improved test method increases confidence in results obtained by utilizing the ASTM G72 autogenous ignition temperature test method and can aid in the oxygen compatibility assessment of highly volatile liquids and other conditions that may lead to false non-ignition results.

Juarez, Alfredo↗
NASA NTRS2016

Improved ASTM G72 Test Method for Ensuring Adequate Fuel-to-Oxidizer Ratios

The ASTM G72/G72M-15 Standard Test Method for Autogenous Ignition Temperature of Liquids and Solids in a High-Pressure Oxygen-Enriched Environment is currently used to evaluate materials for the ignition susceptibility driven by exposure to external heat in an enriched oxygen environment. Testing performed on highly volatile liquids such as cleaning solvents has proven problematic due to inconsistent test results (non-ignitions). Non-ignition results can be misinterpreted as favorable oxygen compatibility, although they are more likely associated with inadequate fuel-to-oxidizer ratios. Forced evaporation during purging and inadequate sample size were identified as two potential causes for inadequate available sample material during testing. In an effort to maintain adequate fuel-to-oxidizer ratios within the reaction vessel during test, several parameters were considered, including sample size, pretest sample chilling, pretest purging, and test pressure. Tests on a variety of solvents exhibiting a range of volatilities are presented in this paper. A proposed improvement to the standard test protocol as a result of this evaluation is also presented. Execution of the final proposed improved test protocol outlines an incremental step method of determining optimal conditions using increased sample sizes while considering test system safety limits. The proposed improved test method increases confidence in results obtained by utilizing the ASTM G72 autogenous ignition temperature test method and can aid in the oxygen compatibility assessment of highly volatile liquids and other conditions that may lead to false non-ignition results.

Juarez, Alfredo↗
NASA NTRS2016

ASTM Committee C28: International Standards for Properties and Performance of Advanced Ceramics-Three Decades of High-Quality, Technically-Rigorous Normalization

Physical and mechanical properties and performance of advanced ceramics and glasses are difficult to measure correctly without the proper techniques. For over three decades, ASTM Committee C28 on Advanced Ceramics, has developed high-quality, technically-rigorous, full-consensus standards (e.g., test methods, practices, guides, terminology) to measure properties and performance of monolithic and composite ceramics that may be applied to glasses in some cases. These standards contain testing particulars for many mechanical, physical, thermal, properties and performance of these materials. As a result these standards are used to generate accurate, reliable, repeatable and complete data. Within Committee C28, users, producers, researchers, designers, academicians, etc. have written, continually updated, and validated through round-robin test programs, 50 standards since the Committee's founding in 1986. This paper provides a detailed retrospective of the 30 years of ASTM Committee C28 including a graphical pictogram listing of C28 standards along with examples of the tangible benefits of standards for advanced ceramics to demonstrate their practical applications.

properties↗
NASA NTRS2016

ASTM Committee C28: International Standards for Properties and Performance of Advanced Ceramics, Three Decades of High-quality, Technically-rigorous Normalization

Physical and mechanical properties and performance of advanced ceramics and glasses are difficult to measure correctly without the proper techniques. For over three decades, ASTM Committee C28 on Advanced Ceramics, has developed high quality, rigorous, full-consensus standards (e.g., test methods, practices, guides, terminology) to measure properties and performance of monolithic and composite ceramics that may be applied to glasses in some cases. These standards testing particulars for many mechanical, physical, thermal, properties and performance of these materials. As a result these standards provide accurate, reliable, repeatable and complete data. Within Committee C28 users, producers, researchers, designers, academicians, etc. have written, continually updated, and validated through round-robin test programs, nearly 50 standards since the Committees founding in 1986. This paper provides a retrospective review of the 30 years of ASTM Committee C28 including a graphical pictogram listing of C28 standards along with examples of the tangible benefits of advanced ceramics standards to demonstrate their practical applications.

properties↗
NASA NTRS2018

ASTM E399 Standard Development - KIsi Analysis Method

The ASTM E399 test method is used to determine the plane‐strain fracture toughness, K (sub IC), for metallic materials. The test consists of monotonically loading a pre-cracked test specimen to failure while recording the applied load and the crack mouth opening displacement. Several test specimen types are allowable per ASTM E399; two common geometries are the compact tension (C(T)) and the single-edge bend (SE(B)) geometries. The test result is an estimate of the plane‐strain fracture toughness, K (sub q), determined by the intercept of the test record with a 95 percent secant-offset construction line. The 95 percent offset represents crack extension corresponding to approximately 2 percent of the original specimen ligament (assuming that all compliance change is the result of crack extension). If the test meets certain validity requirements based on specimen size and test behavior, the result is valid, and K (sub q) equals K (sub IC).

Tilson, William G.↗
NASA NTRS2015

Application of ASTM E-1559 Apparatus to Study H2O Desorption

The NASA James Webb Space Telescope project identified a need to measure water vapor desorption from cryogenic surfaces in order to validate predictions of spacecraft design performance. A review of available scientific literature indicated no such measurements had been reported below 131 K. Contamination control personnel at NASA Goddard Space Flight Center recognized the possibility they readily possessed the means to collect these measurements at lower temperatures using an existing apparatus commonly employed for making outgassing observations. This presentation will relate how the ASTM E-1559 Molekit apparatus was used without physical modification to measure water vapor sublimation down to 120 K and compare this data to existing equilibrium vapor pressure models.

ASTM E-1559↗
NASA NTRS2022

Ruggedness Evaluation of ASTM International Standard Test Methods for Shape Memory Materials: E3097 Standard Test Method for Mechanical Uniaxial Constant Force Thermal Cycling of Shape Memory Alloys

This paper evaluates the ruggedness testing of the newly released ASTM International E3097 Standard Test Method for Mechanical Uniaxial Constant Force Thermal Cycling of Shape Memory Alloys. The ruggedness experiment was designed with eight runs in two replicates, consisting of seven factors of strain rate (ė), heating and cooling rates (Ṫ(heat) and Ṫ(cool), respectively), upper and lower cycle temperatures (UCT and LCT, respectively), hold time (thold), and minimum load (Fmin) imparted on the samples. The results indicate that the hold time factor had no effect on any result variable. The minimum load factor, alternatively, had the greatest effect on several result variables, with the greatest influence on the strains at martensite start and finish (strain variation ~0.1 percent), and the strains at the upper and lower cycle temperatures (strain variation of 0.14 percent). The UCT was found to have a large effect on the austenite and martensite finish tangent line and data intersect, denoted by Af* and Mf*, by ~17 and 4 °C, respectively. The testing methodology, analysis techniques, and resulting conclusions on the ruggedness of the test methods are presented.

shape memory alloy↗