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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 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
NASA NTRS2020

A Brief Overview of the Effects of Impact Damage to Rocket Motor Cases

This Technical Memorandum (TM) presents pertinent results from past experimental work concerning impact damage to composite rocket motor cases. A rocket motor case in this TM refers to filament-wound pressure vessels of a substantial size intended to be used for launch vehicles, such as the new Space Launch System (SLS) rocket. In the early 1980s, as carbon fiber composites were becoming increasingly used on aircraft, concerns about the effects of foreign object impact damage grew, since the compressive strength properties of these composites could be severely affected by impact damage. The tensile properties were not as affected by foreign object impact damage which is fortunate for rocket motor cases as they are driven by tensile loads (burst strength). While great improvements to both carbon fibers and resins have resulted in far superior toughness values compared to the early generation of carbon/epoxy systems, the stigma of composite rocket motor cases being easily damaged and the burst strength compromised persists.

impact damage↗
NASA NTRSDate not supplied

Best Practices, Lessons Learned, and Examples on the Application of Damage Tolerance in Space Structures

Damage tolerance is an important consideration in space structures applications. The intent of damage tolerance is to demonstrate that the structure is robust to the presence of flaws over the service life of the space vehicle. Damage tolerance requirements in documents such as those in NASA, AIAA, and ISO can be challenging to implement. The intent of this paper is three-fold: (1) Provide best practices in the application of damage tolerance requirements for space applications, (2) Provide lessons learned for each of class of hardware, (3) Provide examples of challenging situations encountered in the application of damage tolerance. Examples cover additive manufacturing, composite overwrapped pressure vessels, pressurized structures, liquid rocket engines, thermal protection systems, and other classes of hardware. The philosophy and limitations of leak before burst and proof test logic are also discussed. Finally, a discussion on elastic-plastic fracture mechanics with comparisons to test data will be presented.

Best Practices↗
DOE OSTI2015

Comparison of Two Models for Damage Accumulation in Simulations of System Performance

A comprehensive simulation study of system performance needs to address variations in component behavior, variations in phenomenology, and the coupling between phenomenology and component failure. This paper discusses two models of this: 1. damage accumulation is modeled as a random walk process in each time history, with component failure occurring when damage accumulation reaches a specified threshold; or 2. damage accumulation is modeled mechanistically within each time history, but failure occurs when damage reaches a time-history-specific threshold, sampled at time zero from each component’s distribution of damage tolerance. A limiting case of the latter is classical discrete-event simulation, with component failure times sampled a priori from failure time distributions; but in such models, the failure times are not typically adjusted for operating conditions varying within a time history. Nowadays, as discussed below, it is practical to account for this. The paper compares the interpretations and computational aspects of the two models mentioned above.

42 ENGINEERING↗
DOE OSTI2022

Methods and apparatus for comprehensive characterization of performance attributes and damage thresholds of ultrafast laser optics

It is presently well understood that the operational performance limits of optics are determined by three fundamental attributes: the initiation of laser-induced damage, the growth of damage sites, and the transient (nondamaging) modification of optical parameters. The comprehensive characterization of the performance limitations of ultrafast optics requires consideration of all three fundamental attributes. Here, the vast majority of literature to date, however, has focused primarily on damage-initiation and testing systems that are largely focused on determining the damage-initiation threshold under single- and multipulse excitation. In this work, we discuss a testing apparatus that was designed to offer the capability to adequately characterize all three of these performance attributes under femtosecond, near-infrared laser irradiation. Key aspects of methodology are discussed, including high-dynamic-range energy control, variable beam size, wavelength tunability, B-integral management, and functional performance characterization to explore the true operational limits of the components. Example results for a metal-dielectric mirror demonstrate the test station’s operation.

42 ENGINEERING↗
DOE OSTI2016

Direct observations of damage during unconfined brittle failure of Carrara marble

Abstract To observe and quantify the production of microfracturing from initial yield to failure, we deformed Carrara marble samples in uniaxial compression at 20, 105, and 180°C and continuously observed a region of about 1 mm 2 on an exposed face with a long‐working distance microscope. Using image processing and microscale strain‐mapping techniques, we measured local strains over a length scale of tens of micrometers. By treating the images with various filters, we identified linear damage features, as well as the magnitude of localized strain and the mode of deformation, i.e., shear versus normal deformation. In general, shear deformation is more prevalent after initial yielding, while tensile deformation dominates closer to peak stress. Independent measurements of both stress and microcrack density at different stages of each experiment provide a unique opportunity to explicitly compare the data with damage models. The model of Ashby and Sammis (1990) significantly underestimated the damage that the rock could sustain before peak stress, perhaps owing to the influence of weak grain boundaries on the damage production. In these samples, microcracks tended to form near boundaries before yield stress. During strain hardening, the damage parameters increased rapidly as longer microcracks grew along the boundaries and finally transected grains as loading neared peak stress. The microcrack density can be empirically related to the reduction of Young's modulus; stiffness ratios decay exponentially with increasing microcrack density for T ≤ 105°C.

Tal, Yuval↗
DOE OSTI2023

Nonlinear Impact-Echo Test for Quantitative Evaluation of ASR Damage in Concrete

Nonlinear acoustic methods demonstrate high sensitivity for concrete damage evaluation. Among these methods, nonlinear resonance acoustic methods have been widely used in laboratory tests on small scale test samples. In this study, a nonlinear impact-echo (IE) method for concrete damage evaluation was introduced, in which the IE frequency shift was measured at different impact force levels. The nonlinear IE test and the nonlinear impact resonance acoustic spectroscopy (NIRAS) test share similarities in the experimental setup and analysis method. However, the nonlinear IE test excites a local thickness resonance mode of a member instead of the global resonance vibration. Therefore, the analyzed mode is unaffected by member boundary conditions and is applicable to large concrete structural members. To identify the fundamental IE frequencies, multiple impacts were applied along the members. Once the fundamental IE frequencies were determined, the effectiveness of the nonlinear IE method was evaluated by testing seven concrete beam specimens with varying levels of alkali-silica reaction (ASR) damage. In conclusion, the nonlinear IE test demonstrates high sensitivity to concrete damage and allows for quantitative assessment of the damage state of concrete without a baseline measurement.

36 MATERIALS SCIENCE↗
DOE OSTI2018

A Micro-Mechanism-Based Continuum Corrosion Fatigue Damage Model for Steels

A micro-mechanism-based corrosion fatigue damage model is developed for studying the high-cycle corrosion fatigue of steel from multi-scale viewpoint. The developed physical corrosion fatigue damage model establishes micro-macro relationships between macroscopic continuum damage evolution and collective evolution behavior of microscopic pits and cracks, which can be used to describe the multi-scale corrosion fatigue process of steel. As a case study, the model is used to predict continuum damage evolution and number density of the corrosion pit and short crack of steel component in 5% NaCl water under constant stress amplitude at 20 kHz, and the numerical results are compared with experimental results. It shows that the model is effective and can be used to evaluate the continuum macroscopic corrosion fatigue damage and study microscopic corrosion fatigue mechanisms of steel.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Radiation instability of equal channel angular extruded T91 at ultra-high damage levels

Although several studies have shown that nano-grained alloys have higher radiation resistance than coarse-grained variants, with dense grain boundary structures acting as defect sinks to remove damage, the present study shows the failure of severe deformation to suppress void swelling in T91 alloy at ultra-high damage levels. Fe self-ion irradiation up to 1000 peak dpa produced significantly more swelling in extruded T91 than conventional T91 at 475 °C. Dramatic radiation-enhanced grain growth was observed in the extruded T91, manifested in two rapid grain growth stages. One stage occurs at a relatively low damage level, and the other at a higher damage level beyond 750 peak dpa. The second rapid growth stage is correlated with void swelling and starts at the end of the swelling incubation period. The study suggests that the defect sink properties of the growing grain boundaries under a coarsening process are different from that of stable boundary configurations. When void swelling becomes significant and voids act as a biased sink for vacancies, the growing grain boundaries act as a biased sink for interstitials, leading to rapid growth at higher damage levels.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Synergistically-enhanced ion track formation in pre-damaged strontium titanate by energetic heavy ions

Latent ion tracks created by energetic heavy ions (12 MeV Ti to 946 MeV Au) in single crystal SrTiO 3 are investigated in this paper using Rutherford backscattering spectrometry and scanning transmission electron microscopy. The results demonstrate that pre-existing irradiation damage, introduced via elastic collision processes, interacts synergistically with the electronic energy deposition from energetic heavy ions to enhance formation of latent ion tracks. The average amorphous cross-section increases with the level of pre-damage and is linearly proportional to the electronic energy loss of the ions, with a slope dependent on the pre-damage level. For the highest energy ions (629 MeV Xe and 946 MeV Au), the tracks are continuous over the pre-damaged depth, but become discontinuous beyond the pre-damaged region. Finally, this work provides new understanding and insights on ion-solid interactions that significantly impact the interpretation of latent track formation processes, models of amorphization, and the fabrication of electro-ceramic devices.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Influence of electronic vs nuclear energy loss in radiation damage of Ti 3 SiC 2

We report the thermal conductivity and stability of MAX phases has led to irradiation studies of these materials for their possible application in the hostile environments of high temperature and radiation. Numerous neutron and ion irradiation studies have been conducted that demonstrate that radiation induced modifications consists of lattice strain and increased formation of TiC. Ion beams have been used to simulate damage created by neutrons; however, what is not clear is the effect of varying electronic to nuclear energy loss on the damage evolution within this material. In the present work, changes in c/a within Ti 3 SiC 2 are monitored as a function of energy deposition at constant damage dose following high fluence 9 MeV Ti ion irradiations at room temperature. The results reveal that there is an apparent threshold in the electronic energy loss, above which the c/a ratio and TiC concentration starts to increase with increasing electronic energy loss. Interestingly, this change is independent of the damage dose in displacements per atom. In conclusion, this suggests that inelastic energy dissipation is of paramount importance when selecting ions for simulating damage by energetic neutrons.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Hydroxysafflor yellow A attenuates high glucose-induced pancreatic β-cells oxidative damage via inhibiting JNK/c-jun signaling pathway

Highlights: • High glucose-induced oxidative stress can lead to pancreatic β-cells damage. • HSYA can reduce pancreatic β-cells apoptosis by attenuating oxidative damage. • HSYA can scavenge oxidative stress and inhibit apoptosis through JNK/c-Jun signaling pathway. Pancreatic β-cells apoptosis and dysfunction induced by glucose toxicity were attributed to the formation of excess oxidative damage. Some studies have found that hydroxysafflor yellow A has strong effects to scavenge oxidative stress and inhibit apoptosis. In order to explore the influence of HSYA on oxidative stress induced by high glucose and the potential mechanisms, we set up a high glucose damage model and induced oxidative stress in INS-1 rat insulinoma cells. N-acetylcysteine was added as a group of oxidative stress scavenger. After 72 h of cultivation, the related indexes of oxidative stress (reactive oxygen species, catalase, glutathione peroxidase, lipid peroxidation, and superoxide dismutase), apoptosis (caspase3, parp) and the function of glucose stimulated insulin secretion were determined. In addition, the signaling pathway proteins of C-Jun NH2 -terminal kinases (JNK), phosphorylated JNK, C-jun, phosphorylated C-jun were evaluated. Fluorescence microscopy, qRT-PCR, western blotting were the main methods used in the experiment. Our results showed that hydroxysafflor yellow A reduced pancreatic β-cells apoptosis by attenuating oxidative damage, and JNK/c-Jun signaling pathway was involved. It indicated a significant mechanism for the positive impacts of HSYA on oxidative stress induced by high glucose, and provide important basis for using HSYA in diabetic prevention and therapy.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Real-time visualization of impact damage in monolithic silicon carbide and fibrous silicon carbide ceramic composite

Impact resistance from foreign debris is a critical requirement for brittle ceramic and ceramic composite materials intended for use in the hot-section of gas turbine engines. A design to mitigate against such impact failures necessitates a detailed understanding of the driving failure mechanisms. The present study introduces a unique time-resolved experimental method which advances the latter effort. Specifically, a pulsed synchrotron X-ray source, in phase contrast imaging (PCI) configuration, is used as a medium, to visually characterize the evolution of damage inside the target materials during impact. As a proof of concept, two types of ceramic materials were tested: monolithic silicon carbide and fibrous silicon carbide composite. Impact was performed using a light-gas gun and 1.5 mm diameter spheres of partially stabilized zirconia (PSZ) and silicon nitride (Si 3 N 4 ). The retrieved dynamic X-ray image sequences provided clear outlines of the damage features. In the case of the monolithic ceramic, the impact by a PSZ projectile initially produced a cone crack and complete failure resulted by extension of a median crack. By contrast, the fibrous composite deformed readily prior to cone crack formation. Nearly identical damage features were observed in the monolith for the Si 3 N 4 projectile, with the exception of the added vertical tensile crack. For this same projectile, the fibrous ceramic showed very limited surface deformation and enhanced cone cracking and kinking of laminates along the crack path. The latter response is attributed to the change in projectile properties. Some of the target materials were recovered, and post-mortem analysis via scanning electron microscopy (SEM) showed correlation with observed X-ray damage profiles. Furthermore, simple Hertzian contact was used to estimate damage for the elastic portion of impact. This approach was found to yield a reasonable match with experimental results for the surface displacement near the contact interface.

36 MATERIALS SCIENCE↗
DOE OSTI2018

High-temperature damage evolution in 10 keV He+ irradiated W and W-5Re

Highlights: • High-temperature damage in pure W appeared strongly dependent upon foil thickness. • Visible bubbles occurred at above a threshold fluence of ~ 4.5×10{sup 19} He{sup +}/m{sup 2}. • Dislocations with b = ½ were identified and exhibited a wavy morphology. • The bypass of bubbles by dislocations operated through simple shear. • Rhenium gave rise to ~ 10-40% increase in bubble size and a pronounced change in bubble morphology. - Abstract: High-temperature damage evolution in pure W and W-5Re has been studied by combining transmission electron microscopy and in-situ irradiations with 10 keV He{sup +} ions. The irradiations covered a temperature range of T{sub irr} = 773–1473 K and a fluence range of (4.5–15) × 10{sup 19} He{sup +}/m{sup 2}. In pure W, detailed characterizations have shown that damage evolution is highly dependent upon the foil thickness. Regions of thickness irr from 773 K to 1473 K, a pronounced bubble growth and an increased degree of bubble ordering were observed. In thicker regions (≳100 nm), 1/2<111> dislocation loops and line entanglements were found up to 1473 K, and were often seen to be decorated with helium bubbles. In W-5Re, areas of different foil thickness exhibited only small differences in damage evolution. The densities of bubbles were comparable to those seen in pure W at all temperatures, while the average size of bubbles was found to be ~10–40% higher. The damage microstructure transformed from a mixture of dislocation loops and bubbles at 773 K to dislocation line entanglements decorated with bubbles at 1473 K.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Damage detection in a laboratory-scale wellbore applying Time Reversal and Nonlinear Elastic Wave Spectroscopy (TR NEWS)

We report Time Reversal and Nonlinear Elastic Wave Spectroscopy (TR-NEWS) has been used to focus acoustic energy, and make measurements correlated with damage in a variety of industrial materials. Most studies using TR-NEWS have focused on relatively small objects and may have multiple acoustic sources. In Earth, within energy extraction and carbon sequestration settings, the structure and scale of wellbores makes acoustic focusing challenging, as has been demonstrated through numerical simulations. This paper explores the feasibility of applying TR NEWS for damage detection in wellbores by constructing a laboratory-scale wellbore, and using TR to focus and make dynamic linear and nonlinear elastic measurements on it. During successive cycles of localized mechanical damage induced in the sample, the hysteretic nonlinear elastic parameter α increased with progressive mechanical damage. In addition to these strain-dependent changes in α, the width and peak amplitude of the time reversal focused energy changed near the damage site.

58 GEOSCIENCES↗
DOE OSTI2015

Phosphoramide mustard exposure induces DNA adduct formation and the DNA damage repair response in rat ovarian granulosa cells

Phosphoramide mustard (PM), the ovotoxic metabolite of the anti-cancer agent cyclophosphamide (CPA), destroys rapidly dividing cells by forming NOR-G-OH, NOR-G and G-NOR-G adducts with DNA, potentially leading to DNA damage. A previous study demonstrated that PM induces ovarian DNA damage in rat ovaries. To investigate whether PM induces DNA adduct formation, DNA damage and induction of the DNA repair response, rat spontaneously immortalized granulosa cells (SIGCs) were treated with vehicle control (1% DMSO) or PM (3 or 6 μM) for 24 or 48 h. Cell viability was reduced (P < 0.05) after 48 h of exposure to 3 or 6 μM PM. The NOR-G-OH DNA adduct was detected after 24 h of 6 μM PM exposure, while the more cytotoxic G-NOR-G DNA adduct was formed after 48 h by exposure to both PM concentrations. Phosphorylated H2AX (γH2AX), a marker of DNA double stranded break occurrence, was also increased by PM exposure, coincident with DNA adduct formation. Additionally, induction of genes (Atm, Parp1, Prkdc, Xrcc6, and Brca1) and proteins (ATM, γH2AX, PARP-1, PRKDC, XRCC6, and BRCA1) involved in DNA repair were observed in both a time- and dose-dependent manner. These data support that PM induces DNA adduct formation in ovarian granulosa cells, induces DNA damage and elicits the ovarian DNA repair response. - Highlights: • PM forms ovarian DNA adducts. • DNA damage marker γH2AX increased by PM exposure. • PM induces ovarian DNA double strand break repair.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2024

Assessment of simulated and observed cavitation-induced erosion damage in Spallation Neutron Source target vessels

Cavitation-induced erosion damage in different Spallation Neutron Source (SNS) target designs are simulated using explicit finite element–based techniques and compared with observations of erosion in targets after operation. The efficacy of the previously developed method, called saturation time, was evaluated using erosion-damaged samples from new target designs. A new metric called maximum bubble size was implemented under the rationale that larger cavitation bubbles will collapse more intensely. The maximum cavitation bubble size over 1 ms of simulated time was calculated based on the Rayleigh–Plesset equation for each element integration point and presented as a contour map at the vessel surface for assessing with erosion observations. SNS targets are now operated with helium gas injection to reduce cavitation damage. A simulation method using a material model for the mixture of mercury and gas bubbles was recently developed and used to account for the effect of small gas bubbles on the structural response of the target vessel. Furthermore, this work compares the new method's results with observed cavitation damage. Maps of the calculated maximum bubble size for targets operated with and without gas injection were compared with photographs of erosion damage observed in SNS targets. The patterns in maximum bubble size maps correlated well with observations of erosion patterns in target vessels after service. Advantages and challenges of the maximum bubble size simulation technique are provided, and differences between results from the previous and the newly proposed metric are discussed.

Jiang, Hao↗
DOE OSTI2018

Treatment-damaged hepatocellular carcinoma promotes activities of hepatic stellate cells and fibrosis through GDF15

The aim of this study was to investigate whether treatment-damaged hepatocellular carcinoma (HCC) would accelerate liver cirrhosis through promoting the activities of hepatic stellate cells (HSCs). HCC cells were exposed to chemotherapeutic agent or hypoxia to mimic the transarterial chemoembolization (TACE)-like treatment. Growth differentiation factor 15 (GDF15) expression was increased in cisplatin- or hypoxia-treated HCC cells. Treatment-induced GDF15 increase in HCC cells was mediated by p38MAPK, JNK, ERK1/2 activation. GDF15 from treatment-damaged HCC cells enhanced the proliferation and collagen synthesis of HSCs through ERK1/2- and Smad3-dependent pathways. Metformin significantly reduced the GDF15 production from treatment-damaged HCC cells by targeting JNK. The use of metformin could attenuate the in vivo fibrotic activities of HSCs promoted by treatment-damaged HCC cells and inhibit GDF15 expression. In conclusion, treatment-damaged HCC accelerates fibrosis by promoting the activities of HSCs via GDF15 secretion, which could be reversed by metformin. This provides a potential therapeutic target for alleviating TACE-aggravated liver cirrhosis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

The Moderately (D)efficient Enzyme: Catalysis-Related Damage In Vivo and Its Repair

Enzymes have in vivo life spans. Analysis of life spans, i.e., lifetime totals of catalytic turnovers, suggests that nonsurvivable collateral chemical damage from the very reactions that enzymes catalyze is a common but underdiagnosed cause of enzyme death. Analysis also implies that many enzymes are moderately deficient in that their active-site regions are not naturally as hardened against such collateral damage as they could be, leaving room for improvement by rational design or directed evolution. Enzyme life span might also be improved by engineering systems that repair otherwise fatal active-site damage, of which a handful are known and more are inferred to exist. Unfortunately, the data needed to design and execute such improvements are lacking: there are too few measurements of in vivo life span, and existing information about the extent, nature, and mechanisms of active-site damage and repair during normal enzyme operation is too scarce, anecdotal, and speculative to act on. Fortunately, advances in proteomics, metabolomics, cheminformatics, comparative genomics, and structural biochemistry now empower a systematic, data-driven approach for identifying, predicting, and validating instances of active-site damage and its repair. These capabilities would be practically useful in enzyme redesign and improvement of in-use stability and could change our thinking about which enzymes die young in vivo, and why.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗