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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 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

SU-E-T-420: Failure Effects Mode Analysis for Trigeminal Neuralgia Frameless Radiosurgery

Purpose: Functional radiosurgery has been used successfully in the treatment of trigeminal neuralgia but presents significant challenges to ensuring the high prescription dose is delivered accurately. A review of existing practice should help direct the focus of quality improvement for this treatment regime. Method: Failure modes and effects analysis was used to identify the processes in preparing radiosurgery treatment for TN. The map was developed by a multidisciplinary team including: neurosurgeon, radiation oncology, physicist and therapist. Potential failure modes were identified for each step in the process map as well as potential causes and end effect. A risk priority number was assigned to each cause. Results: The process map identified 66 individual steps (see attached supporting document). Corrective actions were developed for areas of high risk priority number. Wrong site treatment is at higher risk for trigeminal neuralgia treatment due to the lack of site specific pathologic imaging on MR and CT – additional site specific checks were implemented to minimize the risk of wrong site treatment. Failed collision checks resulted from an insufficient collision model in the treatment planning system and a plan template was developed to address this problem. Conclusion: Failure modes and effects analysis is an effective tool for developing quality improvement in high risk radiotherapy procedures such as functional radiosurgery.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

MO-D-213-02: Quality Improvement Through a Failure Mode and Effects Analysis of Pediatric External Beam Radiotherapy

Purpose: To conduct a failure mode and effects analysis (FMEA) as per AAPM Task Group 100 on clinical processes associated with teletherapy, and the development of mitigations for processes with identified high risk. Methods: A FMEA was conducted on clinical processes relating to teletherapy treatment plan development and delivery. Nine major processes were identified for analysis. These steps included CT simulation, data transfer, image registration and segmentation, treatment planning, plan approval and preparation, and initial and subsequent treatments. Process tree mapping was utilized to identify the steps contained within each process. Failure modes (FM) were identified and evaluated with a scale of 1–10 based upon three metrics: the severity of the effect, the probability of occurrence, and the detectability of the cause. The analyzed metrics were scored as follows: severity – no harm = 1, lethal = 10; probability – not likely = 1, certainty = 10; detectability – always detected = 1, undetectable = 10. The three metrics were combined multiplicatively to determine the risk priority number (RPN) which defined the overall score for each FM and the order in which process modifications should be deployed. Results: Eighty-nine procedural steps were identified with 186 FM accompanied by 193 failure effects with 213 potential causes. Eighty-one of the FM were scored with a RPN > 10, and mitigations were developed for FM with RPN values exceeding ten. The initial treatment had the most FM (16) requiring mitigation development followed closely by treatment planning, segmentation, and plan preparation with fourteen each. The maximum RPN was 400 and involved target delineation. Conclusion: The FMEA process proved extremely useful in identifying previously unforeseen risks. New methods were developed and implemented for risk mitigation and error prevention. Similar to findings reported for adult patients, the process leading to the initial treatment has an associated high risk.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

SU-F-R-46: Predicting Distant Failure in Lung SBRT Using Multi-Objective Radiomics Model

Purpose: To predict distant failure in lung stereotactic body radiation therapy (SBRT) in early stage non-small cell lung cancer (NSCLC) by using a new multi-objective radiomics model. Methods: Currently, most available radiomics models use the overall accuracy as the objective function. However, due to data imbalance, a single object may not reflect the performance of a predictive model. Therefore, we developed a multi-objective radiomics model which considers both sensitivity and specificity as the objective functions simultaneously. The new model is used to predict distant failure in lung SBRT using 52 patients treated at our institute. Quantitative imaging features of PET and CT as well as clinical parameters are utilized to build the predictive model. Image features include intensity features (9), textural features (12) and geometric features (8). Clinical parameters for each patient include demographic parameters (4), tumor characteristics (8), treatment faction schemes (4) and pretreatment medicines (6). The modelling procedure consists of two steps: extracting features from segmented tumors in PET and CT; and selecting features and training model parameters based on multi-objective. Support Vector Machine (SVM) is used as the predictive model, while a nondominated sorting-based multi-objective evolutionary computation algorithm II (NSGA-II) is used for solving the multi-objective optimization. Results: The accuracy for PET, clinical, CT, PET+clinical, PET+CT, CT+clinical, PET+CT+clinical are 71.15%, 84.62%, 84.62%, 85.54%, 82.69%, 84.62%, 86.54%, respectively. The sensitivities for the above seven combinations are 41.76%, 58.33%, 50.00%, 50.00%, 41.67%, 41.67%, 58.33%, while the specificities are 80.00%, 92.50%, 90.00%, 97.50%, 92.50%, 97.50%, 97.50%. Conclusion: A new multi-objective radiomics model for predicting distant failure in NSCLC treated with SBRT was developed. The experimental results show that the best performance can be obtained by combining all features.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

SU-F-J-223: Patterns of Failure for Laryngeal Cancer Patients Treated with Definitive IMRT: Comparing Two Different Methods for Determining the Origin of Recurrence From Follow-Up PET/CT Scans

Purpose: To determine patterns of failure in laryngeal cancer treated with definitive IMRT by comparing two different methods for identifying the recurrence epicenter on follow-up PET/CT. Methods: We identified 20 patients treated for laryngeal squamous cell carcinoma with definitive IMRT who had loco-regional recurrence diagnosed on PET/CT. Recurrence PET/CT scans were co-registered with the original treatment planning CT using deformable image registration with the VoxAlign deformation engine in MIM Software. Recurrence volumes were delineated on co-registered follow-up scans using a semi-automatic PETedge tool and two separate methods were used to identify the recurrence point of origin: a) Finding the point within the recurrence volume for which the maximum distance to the surface of the surrounding recurrence volume is smaller than for any other point. b) Finding the point within the recurrence volume with the maximum standardized uptake value (SUVmax), without geometric restrictions.For each method the failure pattern was determined as whether the recurrence origin fell within the original high-dose target volumes GTV70, CTV70, PTV70 (receiving 70Gy), intermediate-risk PTV59 (receiving 59.4Gy) or low-risk PTV54 (receiving 54.1Gy), in the original treatment planning CT. Results: 23 primary/nodal recurrences from the 20 patients were analyzed. The three-dimensional distance between the two different origins was on average 10.5mm (std.dev. 10mm). Most recurrences originated in the high-dose target volumes for both methods with 13 (57%) and 11 (48%) in the GTV70 and 20 (87%) and 20 (87%) in the PTV70 for method a) and b), respectively. There was good agreement between the two methods in classifying the origin target volumes with 69% concordance for GTV70, 89% for CTV70 and 100% for PTV70. Conclusion: With strong agreement in patterns of failure between two separate methods for determining recurrence origin, we conclude that most recurrences occurred within the high-dose treatment region, which influences potential risk-adaptive treatment strategies.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

A resilient network recovery framework against cascading failures with deep graph learning

Because of the increasing importance and dependencies of infrastructure networks and the potential for massive cascading failures in real-world network systems, maintenance optimization to effectively reduce system performance loss caused by diverse disruptions is of significant interest among researchers and practitioners. In this work, a new recovery framework was developed to rapidly identify important system components for maintenance to improve network resilience against cascading failures. Here this work provides distinct advantages to determine an optimal maintenance priority by combining real-time network structure importance with other maintenance prioritization based on customer preference. This approach adopts structural graph embedding and deep reinforcement learning to extract real-time network topology information (such as minimum vertex cover) to update the maintenance priority during the recovery process. Based on the case studies on synthetic networks and a US airport network, the proposed recovery framework with real-time network topology awareness shows better performance than other maintenance prioritization strategies regarding resilience enhancement. This work improves the understanding of how the changing network structure influences maintenance effects. It also provides insights of the practical usefulness of advanced deep learning on helping optimal maintenance prioritization to effectively reduce the intensity and extent of cascading failures.

42 ENGINEERING↗
DOE OSTI2017

Failure Diameter Resolution Study

Previously the SURFplus reactive burn model was calibrated for the TATB based explosive PBX 9502. The calibration was based on fitting Pop plot data, the failure diameter and the limiting detonation speed, and curvature effect data for small curvature. The model failure diameter is determined utilizing 2-D simulations of an unconfined rate stick to find the minimum diameter for which a detonation wave propagates. Here we examine the effect of mesh resolution on an unconfined rate stick with a diameter (10mm) slightly greater than the measured failure diameter (8 to 9 mm).

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2017

Brittle Failure of Low-Carbon Steel Structures at Low Temperatures

The brittle failure of metals at low temperature is analyzed. The temperature of ductile—brittle failure depends on the lattice parameter of the metal, while the temperature of brittle failure depends on the type of lattice, the electron structure, and the presence of impurities at the grain boundaries. Means of increasing the brittle strength of the steel at low temperature are proposed.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Cyber-physical cascading failure and resilience of power grid: A comprehensive review

Smart grid technologies are based on the integration of the cyber network and the power grid into a cyber-physical power system (CPPS). The increasing cyber-physical interdependencies bring about tremendous opportunities for the modeling, monitoring, control, and protection of power grids, but also create new types of vulnerabilities and failure mechanisms threatening the reliability and resiliency of system operation. A major concern regarding the interdependent networks is the cascading failure (CF), where a small initial disturbance/failure in the network results in a seemingly unexpected large-scale failure. Although there has been a significant volume of recent work in the CF research of CPPS, a comprehensive review remains unavailable. This article aims to fill the gap by providing a systematic literature survey regarding the modeling, analysis, and mitigation of CF in CPPS. The open research questions for further research are also discussed. This article allows researchers to easily understand the state of the art of CF research in CPPS and fosters future work required towards full resolutions to the remaining questions and challenges.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2021

Failure in Confined Brazilian Tests on Sandstone

Strength of rocks in the confined tension region, where the minimum principal stress is tensile, has only infrequently been measured and is not well understood. Quasi-static confined Brazilian tests under a range of confining stresses (2.76 to 27.58 MPa) where used to determine the strength of sandstone in the confined tension region. The test results indicate that the strength in the confined tension region was a strong function of the intermediate principal stress: increasing the intermediate principal stress significantly increased the strength of the sandstone. The strength data were well fit by the Mogi–Coulomb criterion, which accounts for the intermediate principal stress. Unconfined Brazilian strength data were not well fit to the Mogi–Coulomb criterion derived from the confined Brazilian test data, consistent with a transition from tensile to shear processes dominating failure with increasing confining pressure. Observations of post-failure fracture surfaces reveal more indication of shear processes with increasing confining pressure. Numerical simulations from combined finite-discrete element method are compared to the experimental results and reflect similar conditions for failure compared to the experimental tests in the confined tension region.

42 ENGINEERING↗
DOE OSTI2016

Failure Mechanisms of Hollow Fiber Supported Ionic Liquid Membranes

Hollow fiber supported ionic liquid membranes (SILMs) were tested using the bubble point method to investigate potential failure modes, including the maximum transmembrane pressure before loss of the ionic liquid from the support. Porous hollow fiber supports were fabricated with different pore morphologies using Matrimid® and Torlon® as the polymeric material and 1-hexyl-3-methylimidalzolium bis(trifluoromethylsulfonyl)imide ([C6mim][Tf2N]) as the ionic liquid (IL) component. Hollow fiber SILMs were tested for their maximum pressure before failure, with pressure applied either from the bore side or shell side. It was found that the membranes exhibited one or more of three different modes of failure when pressurized: liquid loss (occurring at the bubble point), rupture, and collapse.

rupture↗
DOE OSTI2016

MAGNETAR OUTBURSTS FROM AVALANCHES OF HALL WAVES AND CRUSTAL FAILURES

We explore the interaction between Hall waves and mechanical failures inside a magnetar crust, using detailed one-dimensional models that consider temperature-sensitive plastic flow, heat transport, and cooling by neutrino emission, as well as the coupling of the crustal motion to the magnetosphere. We find that the dynamics is enriched and accelerated by the fast, short-wavelength Hall waves that are emitted by each failure. The waves propagate and cause failures elsewhere, triggering avalanches. We argue that these avalanches are the likely sources of outbursts in transient magnetars.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1927

Duralumin - Defects and Failures

It is proposed in this paper to identify some of the defects and failures in duralumin most frequently encountered by the aircraft industry with a view to indicate their importance. The defects and failures in duralumin may be classified into the following groups: 1) defects produced during manufacture; 2) defects produced during fabrication; 3) corrosion and erosion; and 4) fatigue failures. Only the first two will be covered in this report.

DURALUMIN - DEFECTS & FAILURES↗
NASA NTRS1995

Detecting Hidden Failure Modes in Critical, Embedded Software

This experience report describes a method that has been used successfully to detect hidden failure modes in critical, embedded spacecraft software. The method is an adaptation of an earlier, controversial approach called failure modes and effects analysis. The adapted method was found to be well-suited to identifying latent software design weaknesses involving complex system interactions and dependencies in the two applications described here. This experience may be useful for other high-integrity software systems in which the possibility of hidden failure modes is a major concern.

detecting software failure design analysis↗
NASA NTRS1993

Some Observations of Solder Joint Failure Under Tensile-Compressive Stress

It has long been known that solder joints under mechanical stress are subject to failure. In early electronic systems, such failures were avoided primarily by avoiding the use of solder as a mechanical structural component. The rule was to first make sound wire connections that did not depend mechanically on solder, and only then to solder them. Careful design and miniaturization in modern electronic systems limits the mechanical stresses exerted on solder joints to values less than their yield points, and these joints have become integral parts of the mechanical structures. Unfortunately, while these joints are strong enough when new, they have proven vulnerable to fatigue failures as they age.Details of the fatigue process are poorly understood, making predictions of expected lifetimes difficult.

solder joints fatigue failure thermal cycling test↗
NASA NTRSDate not supplied

Multiscale Failure Analysis of a 3D Woven Unit Cell Containing Defects

Multiscale failure simulations have been performed for a Three-dimensional woven composite unit cell considering five, or more, length scales spanning the woven composite mesoscale to the sub-microscale voids. The multiscale recursive micromechanics approach, which enables recursive integration of general micromechanics theories over an arbitrary number of length scales, has been employed within the NASA Multiscale Analysis Tool. The multiscale model uses both the generalized method of cells and Mori-Tanaka micromechanics theories, and considers failure in the constituent materials using a simple damage model. Baseline results, containing distributed voids, are compared to uniaxial experimental data for an AS4 carbon fiber/ RTM6 epoxy matrix 3D orthogonal woven composite with good agreement in terms of global stiffness and global failure stress. The simulations demonstrate that the 3D woven composite exhibits damage tolerance through sustaining increasing axial load far beyond the first initiation of damage. The multiscale model is used to examine the nonlinear response of the material to other loading conditions. Case studies, motivated by X-ray computed tomography data, are presented on the effects of manufacturing induced voids and cracks.

3D woven↗
NASA NTRSDate not supplied

Battery Failure Databank

The Battery Failure Databank contains thermal runaway results gathered from nearly 300 small format fractional thermal runaway calorimetry (S-FTRC) experiments. A majority of these experiments were conducted at synchrotron facilities where high-speed x-ray videography was conducted of the cell while tested inside of the S-FTRC. The databank is a two-component system which consists of a Microsoft ExcelTM spreadsheet which provides S-FTRC results in tabular format and a radiographic video library containing the high-speed x-ray videos. Overall, the databank provides thermal results from S-FTRC experiments conducted on a mixture of commercially available lithium-ion (Li-ion) cells and specialized Li-ion test cells with varying cell format (18650, 21700, and D-cell) and trigger mechanism (heaters, heaters plus internal short circuiting device, and nail penetration). The radiography video component provides insight into the initiation and propagation of TR in the cells, in addition to consequences of TR measured by the FTRC. Fractions of mass ejected for the cell types are separated into regimes based on the different failure modes of the cells, such as purely venting, partial ejection, and total ejection. With knowledge of the rate and characterization of the internal degradation of the cells during TR, and the amounts of mass ejected and unrecovered, the extent of TR, and therefore the mitigation of TR, is revealed relative to cell types and failure modes.

Lithium-ion battery↗
NASA NTRS2020

Popcorning Failures in Polymer and MnO2 Tantalum Capacitors

Popcorning is a well-known effect in plastic encapsulated microcircuits (PEM) and it occurs in chip tantalum capacitors. The sensitivity of components to the presence of moisture during soldering is characterized by the moisture sensitivity level (MSL); however, contrary to PEMs, there is no standard procedure for establishing MSL for tantalum capacitors.The effect of absorbed moisture on soldering related degradation and failures in tantalum capacitors have not been studied properly yet, and there is no sufficient information regarding the difference in the sensitivity to soldering between polymer and MnO2 capacitors. In this work, 16 types of polymer and 9 types of MnO2 tantalum capacitors with different moisture content have been tested before and after reflow soldering. The level of moisture release during soldering has been estimated and thermo-mechanical analysis used to assess deformation of capacitorsduring soldering simulations. Results show that moisture uptake in similar parts is approximately two times greater in polymer than in MnO2 capacitors. Cracking of the case and degradation of parameters can occur in both types of parts, but MnO2 capacitors are much more likely to fail catastrophically with a short circuit and possible ignition during the first power-on cycle. This type of failure in MnO2 capacitors is lot-related, can occur even at derated voltages and relatively low levels of moisture sorption that corresponds to room conditions. Baking before soldering is an effective measure to prevent failures even in lots susceptible to popcorning damage.

Capacitor↗
NASA NTRS2021

NASA Engineering and Safety Center Technical Bulletin No. 21-05: Industry Recommendations from Arecibo Observatory Zinc Spelter Socket Joint Failure Analysis

A structural analysis and forensic investigation concluded that the Arecibo Observatory M4N socket joint failure in August 2020 was primarily due to cumulative damage caused by initially low structural design margins and a high percentage of sustained load, resulting in zinc creep deformation, progressive internal socket wire damage, and eventual loss of joint capacity. Open spelter sockets of this type are used throughout industry in stay cables. Recommendations are proposed to prevent failures of similar socket joints, including verification of positive stress margins in socket joint wires for all failure modes, periodic visual inspections with pass/fail criteria for zinc extrusion that are tied to structural qualification, and revisiting codes/ industry standards to capture lessons learned.

Arecibo Observatory↗