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Results for “accelerated life testing”

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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

Slocum-TREC Thermal Glider

JPL is now teaming with Teledyne-Webb-Research to produce the first thermal glider that uses PCM for direct buoyancy control (not electronic pumps) and to produce all other required electricity. TWR has increased electrical production total efficiency from 0.45 to 0.61. JPL performed over 6000 cycles (2.4 years) of accelerated life testing of a piston accumulator. Design, fabrication, and testing will be performed in 2012, with deployment by Rutgers University in late 2012. The proposed goal of the ocean endurance tests was 3 months, but will be extended to at last 1 year. The piston accumulator was cycled over 6,000 times in a three-month period in order to simulate continuous glider life of about 2.4 years, The life test data suggests that we might accumulate roughly 0.5 cc of gas in the oil bladders for each cycle. PCM canisters will be fabricated with a compressed aluminum foam core, 7.5% foam selected (< 42 minutes to freeze anticipated) An Axi 5345/18 3-Phase AC alternator selected for power generation, 61% energy storage efficiency A 4-Cell A123 Energy Storage Systems battery selected for energy storage, buss voltage 14.4 to 12.5 V (13.2 V nominal) Glider deployment expected in late 2012

energy harvesting↗
NASA NTRS2012

Accelerated Aging Experiments for Capacitor Health Monitoring and Prognostics

This paper discusses experimental setups for health monitoring and prognostics of electrolytic capacitors under nominal operation and accelerated aging conditions. Electrolytic capacitors have higher failure rates than other components in electronic systems like power drives, power converters etc. Our current work focuses on developing first-principles-based degradation models for electrolytic capacitors under varying electrical and thermal stress conditions. Prognostics and health management for electronic systems aims to predict the onset of faults, study causes for system degradation, and accurately compute remaining useful life. Accelerated life test methods are often used in prognostics research as a way to model multiple causes and assess the effects of the degradation process through time. It also allows for the identification and study of different failure mechanisms and their relationships under different operating conditions. Experiments are designed for aging of the capacitors such that the degradation pattern induced by the aging can be monitored and analyzed. Experimental setups and data collection methods are presented to demonstrate this approach.

Prognostics of Electronics↗
NASA NTRS2015

Insulation Resistance Degradation in Ni-BaTiO3 Multilayer Ceramic Capacitors

Insulation resistance (IR) degradation in NiBaTiO3 multilayer ceramic capacitors has been characterized by the measurement of both time to failure (TTF) and direct current leakage current as a function of stress time under highly accelerated life test conditions. The measured leakage current time dependence data fit well to an exponential form, and a characteristic growth time tau (sub SD) can be determined. A greater value of tau (sub SD) represents a slower IR degradation process. Oxygen vacancy migration and localization at the grain boundary region results in the reduction of the Schottky barrier height and has been found to be the main reason for IR degradation in NiBaTiO3 capacitors. The reduction of barrier height as a function oftime follows an exponential relation of phi (t ) = phi (0) e (exp -2Kt), where 13 the degradation rate constant K Koe (Ek/kT) is inversely proportional to the mean TTF (MTTF) and can be determined using an Arrhenius plot. For oxygen vacancy electromigration, a lower barrier height phi (0) will favor a slow IR degradation process, but a lower phi (0) will also promote electronic carrier conduction across the barrier and decrease the IR. As a result, a moderate barrier height phi (0) (and therefore a moderate IR value) with a longer MTTF (smaller degradation rate constant K) will result in a minimized IR degradation process and the most improved reliability in NiBaTiO3 multilayer ceramic capacitors.

reliability↗
NASA NTRS2015

Leakage Currents in Low-Voltage PME and BME Ceramic Capacitors

Introduction of BME capacitors to high-reliability electronics as a replacement for PME capacitors requires better understanding of changes in performance and reliability of MLCCs to set justified screening and qualification requirements. In this work, absorption and leakage currents in various lots of commercial and military grade X7R MLCCs rated to 100V and less have been measured to reveal difference in behavior of PME and BME capacitors in a wide range of voltages and temperatures. Degradation of leakage currents and failures in virgin capacitors and capacitors with introduced cracks has been studied at different voltages and temperatures during step stress highly accelerated life testing. Mechanisms of charge absorption, conduction and degradation have been discussed and a failure model in capacitors with defects suggested.

base metal electrode capacitor (BME)↗
NASA NTRS2015

Insulation Resistance Degradation in Ni-BaTiO3 Multilayer Ceramic Capacitors

Insulation resistance (IR) degradation in Ni-BaTiO3 multilayer ceramic capacitors has been characterized by the measurement of both time to failure and direct-current (DC) leakage current as a function of stress time under highly accelerated life test conditions. The measured leakage current-time dependence data fit well to an exponential form, and a characteristic growth time SD can be determined. A greater value of tau(sub SD) represents a slower IR degradation process. Oxygen vacancy migration and localization at the grain boundary region results in the reduction of the Schottky barrier height and has been found to be the main reason for IR degradation in Ni-BaTiO3 capacitors. The reduction of barrier height as a function of time follows an exponential relation of phi (𝑡)=phi (0)e(exp -2Κt), where the degradation rate constant 𝐾=𝐾o𝑒(𝐸𝑘/𝑘𝑇) is inversely proportional to the mean time to failure (MTTF) and can be determined using an Arrhenius plot. For oxygen vacancy electromigration, a lower barrier height phi(0) will favor a slow IR degradation process, but a lower phi(0) will also promote electronic carrier conduction across the barrier and decrease the insulation resistance. As a result, a moderate barrier height phi(0) (and therefore a moderate IR value) with a longer MTTF (smaller degradation rate constant 𝐾) will result in a minimized IR degradation process and the most improved reliability in Ni-BaTiO3 multilayer ceramic capacitors.

dielectric degradation↗
NASA NTRS2017

Additive Manufacturing (AM) Activities and Non-Destructive Evaluation (NDE) at GSFC

NASA personnel will be meeting with a delegation from the Japan Aerospace Exploration Agency (JAXA) Office of Safety and Mission Assurance (OSMA) at Langley Research Center on 2217 through 3217. The purpose of the meeting is a technical interchange between NASA and JAXA to discuss Non-Destructive Evaluation (NDE) of Additive Manufacturing (AM) parts and the HALT process (relates to accelerated life testing). The visitors will be a small group of Japanese citizens. Goddard Space Flight Center (GSFC) has been asked to participate in the meeting, either in person or via teleconference. This presentation covers NDE efforts at GSFC and provides a cursory overview of AM and lab capabilities.

additive manufacturing↗
NASA NTRS2011

Reliability Evaluation of Base-Metal-Electrode (BME) Multilayer Ceramic Capacitors for Space Applications

This paper reports reliability evaluation of BME ceramic capacitors for possible high reliability space-level applications. The study is focused on the construction and microstructure of BME capacitors and their impacts on the capacitor life reliability. First, the examinations of the construction and microstructure of commercial-off-the-shelf (COTS) BME capacitors show great variance in dielectric layer thickness, even among BME capacitors with the same rated voltage. Compared to PME (precious-metal-electrode) capacitors, BME capacitors exhibit a denser and more uniform microstructure, with an average grain size between 0.3 and approximately 0.5 micrometers, which is much less than that of most PME capacitors. The primary reasons that a BME capacitor can be fabricated with more internal electrode layers and less dielectric layer thickness is that it has a fine-grained microstructure and does not shrink much during ceramic sintering. This results in the BME capacitors a very high volumetric efficiency. The reliability of BME and PME capacitors was investigated using highly accelerated life testing (HALT) and regular life testing as per MIL-PRF-123. Most BME capacitors were found to fail· with an early dielectric wearout, followed by a rapid wearout failure mode during the HALT test. When most of the early wearout failures were removed, BME capacitors exhibited a minimum mean time-to-failure of more than 10(exp 5) years. Dielectric thickness was found to be a critical parameter for the reliability of BME capacitors. The number of stacked grains in a dielectric layer appears to play a significant role in determining BME capacitor reliability. Although dielectric layer thickness varies for a given rated voltage in BME capacitors, the number of stacked grains is relatively consistent, typically between 10 and 20. This may suggest that the number of grains per dielectric layer is more critical than the thickness itself for determining the rated voltage and the life expectancy of the BME capacitor. Since BME capacitors have a much smaller grain size than PME capacitors, it is reasonable to predict that BME capacitors with thinner dielectric layers may have an equivalent life expectancy to that of PME capacitors with thicker dielectric layers.

Liu, David (Donghang)↗
NASA NTRS2017

Evaluation of Series T22 Wet Tantalum Capacitors

Several types of advanced wet tantalum capacitors, and series T22 in particular, are designed without internal Teflon sealing that is used for military grade, CLR style capacitors. This raises concerns regarding hermeticity of the single seal parts and their capability to withstand high internal gas pressures that might develop during operation in space. To address these issues, T22 series capacitors rated to 50 V and 125 V were subjected to highly accelerated life testing (HALT) at 125 C and rated voltage and step stress random vibration testing (RVT). To simulate conditions of storage or operation under increased internal gas pressure, the parts were stored at temperature of 150 C for 2500 hr (HTS150). Electrical characteristics of the parts were measured through the storage testing and the hermeticity leak rate was tested before and after HTS150. To assess thermo-mechanical robustness of the part, capacitors were manually soldered onto printed wired boards (PWB) and stressed by 1000 temperature cycles between -55 C and +125 C. The effect of temperature cycling was assessed by additional HALT at different temperatures. Results show that T22 series capacitors have robust design and can satisfy requirements for space applications.

Wet tantalum capacitors↗
NASA NTRS2017

Reliability Issues with PME and BME Ceramic Capacitors

This work is a review of reliability issues specific for low-voltage precious metal electrode (PME) and base metal electrode (BME) multilayer ceramic capacitors (MLCC). A special attention is given to degradation and failures in capacitors with defects, in particular with cracks. Temperature and voltage reliability acceleration factors have been calculated based on approximation of distributions of degradation rates of leakage currents using a general log-linear Weibull model. Results show a substantial difference in behavior of BME and PME capacitors with defects. Mechanisms of degradation and failures in humid and dry environments and risks of overstressing capacitors during highly accelerated life testing (HALT) are discussed.

Teverovsky, Alexander↗
NASA NTRSDate not supplied

Martian Dust Abrasion Damage on Solar Arrays: HALT Experimental Investigation and Opportunity Rover Performance Analysis

We explored the utility of ground-based highly accelerated life testing (HALT) on epitaxial lift-off (ELO) triple-junction coverglass interconnected cells (CICs) after exposure to simulated Martian dust storms. Dust storm impingement was replicated by sandblasting CICs with Mars dust simulant replicating conditions similar to the weather conditions reported by the Viking landers. We observed that even in cases when there are no observable open circuit voltage (VOC) losses, the minority carrier lifetime is reduced. Short circuit current (JSC) losses can be recovered upon cleaning, suggesting JSC losses are not linked to permanent damage, like cell cracking. This suggests a permanent degradation could be determined by quantifying the difference between recoverable and non-recoverable power loss. We mined field data from the Mars Exploration Rover, Opportunity and extracted a degradation rate to compare to our experimental data. We found exceptional agreement between 4.9 Martian years of mined field data (9.4%) and the irreversible damage observed in our HALT experiment (9.7%). We demonstrate that the laboratory method for exposing CICs to Martian dust storm conditions well represents the physical reality of long duration CIC operation on Mars.

Lyndsey McMillon-Brown↗
NASA NTRSDate not supplied

Evaluation of Automotive Grade Resistors for Space Flight

Over the past decade, electronic, electrical, and electromechanical (EEE) parts for space applications have undergone significant changes, largely driven by CubeSat and commercial space developers pushing the boundaries on the utilization of commercial parts in space. Global product shortages and shipping delays are still impacting space flight project deadlines. Many projects have turned to automotive grade resistors as an alternate to their MIL-SPEC counterparts to fulfill requirements. In addition, automotive grade resistors may offer designers a wider range of parts to consider. A recent NASA study recommended the use of high-volume manufactured commercial components for space applications provided these components show evidence of stringent fabrication controls and thorough reliability monitoring practices [1]. Automotive grade components have stringent qualification requirements per the Automotive Electronic Council (AEC). However, the end user usually does not have insight into the practices the manufacturer may use to reduce/eliminate infant mortality nor for compliance to all datasheet specifications. Screening, Life and Accelerated Life testing on a set of standard automotive-grade chip resistors is proposed to evaluate the reliability of these components. Requirements from both the AEC-Q (Automotive Electronic Council Qualification) and EEE-INST-002 (Instructions for EEE Parts Selection, Screening, Qualification, and Derating) for resistors is compared and discussed. The resistors have been tested by using a modified methodology from EEE-INST-002 to evaluate their reliability for space flight projects. The findings of this study indicate that the underlying degradation mechanisms at rated temperature and power are best represented by power law models with a fitted exponent between 0 and 1. A linear model is more conservative which compensates for potential model uncertainty given the wide range of design and materials used in automotive resistors, while still providing useful long-term resistance drift estimates. No electrical anomalies or failures were observed throughout the 1,000-hour Life Tests other than small in tolerance resistance drift aging. Degradation models were utilized to quantify and extrapolate the long-term resistance drift under operating conditions for the components. The models demonstrated that some automotive-grade resistors are likely to operate 10 years at nominal usage conditions while others might fail earlier.

Zainab Abdullahi↗
NASA NTRSDate not supplied

Evaluation of Automotive Grade Resistors for Space Flight

Over the past decade, electronic, electrical, and electromechanical (EEE) parts for space applications have undergone significant changes, largely driven by CubeSat and commercial space developers pushing the boundaries on the utilization of commercial parts in space. Global product shortages and shipping delays are still impacting space flight project deadlines. Many projects have turned to automotive grade resistors as an alternate to their MILSPEC counterparts to fulfill requirements. In addition, automotive grade resistors may offer designers a wider range of parts to consider. A recent NASA study recommended the use of high-volume manufactured commercial components for space applications provided these components show evidence of stringent fabrication controls and thorough reliability monitoring practices. Automotive grade components have stringent qualification requirements per the Automotive Electronic Council (AEC). However, the end user usually does not have insight into the practices the manufacturer may use to reduce/eliminate infant mortality nor for compliance to all datasheet specifications. Screening, Life and Accelerated Life testing on a set of standard automotive-grade chip resistors is proposed to evaluate the reliability of these components. Requirements from both the AEC-Q (Automotive Electronic Council Qualification) and EEE-INST-002 (Instructions for EEE Parts Selection, Screening, Qualification, and Derating) for resistors is compared and discussed. The resistors have been tested by using a modified methodology from EEEINST-002 to evaluate their reliability for space flight projects. The findings of this study indicate that the underlying degradation mechanisms at rated temperature and power are best represented by power law models with a fitted exponent between 0 and 1. A linear model is more conservative which compensates for potential model uncertainty given the wide range of design and materials used in automotive resistors, while still providing useful long-term resistance drift estimates. No electrical anomalies or failures were observed throughout the 1000-hour Life Tests other than small in tolerance resistance drift aging. Degradation models were utilized to quantify and extrapolate the long-term resistance drift under operating conditions for the components. The models demonstrated that some automotive-grade resistors are likely to operate 10 years at nominal usage conditions while others might fail earlier.

Zainab Abdullahi↗
NASA NTRS1996

Mir Cooperative Solar Array Project Accelerated Life Thermal Cycling Test

The Mir Cooperative Solar Array (MCSA) project was a joint U.S./Russian effort to build a photovoltaic (PV) solar array and deliver it to the Russian space station Mir. The MCSA will be used to increase the electrical power on Mir and provide PV array performance data in support of Phase 1 of the International Space Station. The MCSA was brought to Mir by space shuttle Atlantis in November 1995. This report describes an accelerated thermal life cycle test which was performed on two samples of the MCSA. In eight months time, two MCSA solar array 'mini' panel test articles were simultaneously put through 24,000 thermal cycles. There was no significant degradation in the structural integrity of the test articles and no electrical degradation, not including one cell damaged early and removed from consideration. The nature of the performance degradation caused by this one cell is briefly discussed. As a result of this test, changes were made to improve some aspects of the solar cell coupon-to-support frame interface on the flight unit. It was concluded from the results that the integration of the U.S. solar cell modules with the Russian support structure would be able to withstand at least 24,000 thermal cycles (4 years on-orbit). This was considered a successful development test.

Hoffman, David J.↗
DOE OSTI2023

Accelerated test protocols to predict service life and durability of solid oxide fuel cells

Reliable accelerated test protocols are needed for solid oxide fuel cell research to facilitate rapid learning on key durability issues, identify potential modes of failure expeditiously, and eventually predict the calendar lifetime of an electrochemical cell. In this work, solid oxide fuel cells operated at a constant current density were compared to cells undergoing accelerated measurements, which are composed of intermittent current injection to the cell. A general accelerated test profile was developed by cycling a solid oxide fuel cell from open circuit to a predetermined operating current density that is the same as the current density during a steady-state operation, to accelerate the local redox environment. The following parameters were studied: current density, operation temperature, moist level, sintering temperature, cycling current, cycling frequency, and operation time. Up to 1,320,000 cycles were generated in this work. The cell degradation was accelerated by nearly 10 times, suggesting the feasibility of using this protocol for acceleration test to predict life performance and durability of solid oxide fuel cells.

08 HYDROGEN↗
NASA NTRS1971

Accelerated battery-life testing - A concept

Test program, employing empirical, statistical and physical methods, determines service life and failure probabilities of electrochemical cells and batteries, and is applicable to testing mechanical, electrical, and chemical devices. Data obtained aids long-term performance prediction of battery or cell.

Mccallum, J.↗
NASA NTRS2007

Computational Modeling Develops Ultra-Hard Steel

Glenn Research Center's Mechanical Components Branch developed a spiral bevel or face gear test rig for testing thermal behavior, surface fatigue, strain, vibration, and noise; a full-scale, 500-horsepower helicopter main-rotor transmission testing stand; a gear rig that allows fundamental studies of the dynamic behavior of gear systems and gear noise; and a high-speed helical gear test for analyzing thermal behavior for rotorcraft. The test rig provides accelerated fatigue life testing for standard spur gears at speeds of up to 10,000 rotations per minute. The test rig enables engineers to investigate the effects of materials, heat treat, shot peen, lubricants, and other factors on the gear's performance. QuesTek Innovations LLC, based in Evanston, Illinois, recently developed a carburized, martensitic gear steel with an ultra-hard case using its computational design methodology, but needed to verify surface fatigue, lifecycle performance, and overall reliability. The Battelle Memorial Institute introduced the company to researchers at Glenn's Mechanical Components Branch and facilitated a partnership allowing researchers at the NASA Center to conduct spur gear fatigue testing for the company. Testing revealed that QuesTek's gear steel outperforms the current state-of-the-art alloys used for aviation gears in contact fatigue by almost 300 percent. With the confidence and credibility provided by the NASA testing, QuesTek is commercializing two new steel alloys. Uses for this new class of steel are limitless in areas that demand exceptional strength for high throughput applications.

Source record↗
NASA NTRS1978

Accelerated test modeling

Cycle life regression model, cycle life prediction model, and acceleration factors are discussed. A method was presented to: (1) select a mathematical model; (2) determine model coefficients using accelerated test data; (3) test model fit of the accelerated test data; and (4) predict normal packs.

Schwartz, D.↗