Event Of Catastrophic Failure Research Articles

A multiscale discrete fiber model of failure in heterogeneous tissues: Applications to remodeled cerebral aneurysms

Damage-accumulation failure models are broadly used to examine tissue property changes caused by mechanical loading. However, damage accumulation models are purely phenomenological. The underlying justification in using this type of model is often that damage occurs to the extracellular fibers and/or cells which changes the fundamental mechanical behavior of the system. In this work, we seek to align damage accumulation models with microstructural models to predict alterations in the mechanical behavior of biological materials that arise from structural heterogeneity associated with nonuniform remodeling of tissues. Further, we seek to extend this multiscale model toward assessing catastrophic failure events such as cerebral aneurysm rupture. First, we demonstrate that a model made up of linear elastin and actin and nonlinear collagen fibers can replicate bot the pre-failure and failure tissue-scale mechanics of uniaxially-stretched cerebral aneurysms. Next, we investigate how mechanical heterogeneities, like those observed in cerebral aneurysms, influence fiber and tissue failure. Notably, we find that failure occurs and the interface between regions of high and low material stiffness, suggesting that spatial mechanical heterogeneity influences aneurysm failure behavior. This model system is a step toward linking structural changes in growth and remodeling to failure properties.

Localized Stress Effects on the Single Event Effects Sensitivity of Microelectronics

Understanding the single event effects (SEE) sensitivity of microelectronic devices and circuits is essential for long-term mission success in ionizing radiation environments. SEEs occur when a single ionizing particle strikes a device with enough energy to cause anomalous malfunction or even a catastrophic failure event. It is conventionally viewed as an electrical phenomenon, whereas this study investigates the possible role of multi-physics. Specifically, we show that localized mechanical stress in electronic devices significantly impacts the degree of SEE sensitivity. We present a technique that indirectly maps both electrical and mechanical field localization to spatially map SEE sensitivity without any need for radiation test sources. It is demonstrated on the operational amplifier LM124 under both pristine and stressed conditions. To validate our hypothesis, our experimental results are compared with those obtained from the well-established pulsed laser SEE technique. Excellent agreement between these results supports our hypothesis that SEE susceptibility may have fundamental roots in both electrical and mechanical fields. Therefore, the ability to map the localizations in these fields may indirectly map the SEE sensitivity of large area electronics, which is very expensive in time and resources.

A Comprehensive Seismic Monitoring of the Pillar Threatening the World Cultural Heritage Site Chauvet‐Pont d'Arc Cave, Toward Rock Damage Assessment

AbstractFragile geological features must undergo frequent structural health assessments to prevent catastrophic failure events. The mechanical behavior of natural sites is largely guided by vibrations of the earth and environmental exposure, but damage is rarely assessed, except empirically. The Chauvet‐Pont d’Arc cave, a UNESCO World Heritage Site, represents a shining example of fragility that would benefit from monitoring. It is overhung by a rock column known as Abraham's pillar that extends out from the cliff like a natural tuning fork. For this study, we monitored dancing movements of this pillar for over 2 years to analyze its elastic response to weather conditions. Using ambient‐seismic‐noise‐based methods, we identified the pillar's first two natural resonance modes. Through extensive monitoring of the site, we observed the striking temporal evolution of these two resonance frequencies on hourly, daily, seasonal, and pluriannual scales in response to changes in air temperature and insolation. Based on thermo‐acousto‐elastic modeling with a simplified 3D geometric structure, we determined how thermally‐induced stress stiffening affects the rock material, by applying convective and radiative heat fluxes to the model. From the results obtained, we suggest a novel quantitative method based on daily observations that can estimate the level of damage within the rock material. Our work provides a foundation for distinguishing between reversible processes and damage for hazard studies in the frame of climate change. Such knowledge is crucial not only for the preservation of heritage sites but also for enhancing risk assessment protocols and informing conservation efforts worldwide.

Bayesian learning for the robust verification of autonomous robots

Autonomous robots used in infrastructure inspection, space exploration and other critical missions operate in highly dynamic environments. As such, they must continually verify their ability to complete the tasks associated with these missions safely and effectively. Here we present a Bayesian learning framework that enables this runtime verification of autonomous robots. The framework uses prior knowledge and observations of the verified robot to learn expected ranges for the occurrence rates of regular and singular (e.g., catastrophic failure) events. Interval continuous-time Markov models defined using these ranges are then analysed to obtain expected intervals of variation for system properties such as mission duration and success probability. We apply the framework to an autonomous robotic mission for underwater infrastructure inspection and repair. The formal proofs and experiments presented in the paper show that our framework produces results that reflect the uncertainty intrinsic to many real-world systems, enabling the robust verification of their quantitative properties under parametric uncertainty.

Multi-source data analysis to assess the past and present kinematics of the Pisciotta Deep-Seated Gravitational Slope Deformation (southern Italy)

Although Deep-Seated Gravitational Slope Deformations are well-known in the literature, their evolution and kinematics are still poorly understood. Their behavior is often complex and characterized by small movements associated with steady-state creep, alternating with periods of stasis, or accelerating downslope movements that, in some cases, could result in sudden and catastrophic failure events. Therefore, a multidisciplinary approach is often required. In this work, we shed light on the complex geometry and kinematics of the Pisciotta DSGSD, a deep-seated roto-translational sliding involving structurally complex turbiditic rock mass and interacting with man-made infrastructures. To reveal the geometrical features and the spatial and temporal behavior of the analyzed phenomenon, a multidisciplinary investigation was performed. Typical DSGSD landforms were mapped employing in-situ surveys, aided by stereoscopic analysis of historical aerial images and high-resolution drone-based mapping. Structural data and ancillary ground-based surveys revealed the presence of a highly weathered and folded turbiditic sequence, with competent sandstone and calcarenite units alternated by tectonically disrupted, weak argillite and mudrock layers. Remote sensing measurements from optical imagery and Synthetic Aperture Radar satellite data assessed the DSGSD's past and current kinematics, allowing to distinguish a pre-failure period with accelerating displacement rates, a failure period with maximum displacement rates, and a current post-failure period with decelerating displacement rates. Analytical modeling established the deep reach (up to 85 m) of the studied DSGSD as it allowed the estimation of its bottom surface and volume, as verified by available boreholes and inclinometric measurements. Furthermore, numerical modeling outcomes highlighted how the progressive weakening and alteration of the DSGSD material, in conjunction with changes in groundwater dynamics, serve as the primary mechanisms driving the observed kinematics. The models also revealed the intricate interaction between the DSGSD and the neighboring infrastructures.

Yielding, shear banding, and brittle failure of amorphous materials

Widespread processes in nature and technology are governed by the dynamical transition whereby a material in an initially solid-like state then yields plastically. Major unresolved questions concern whether any material will yield smoothly and gradually (ductile behaviour) or fail abruptly and catastrophically (brittle behaviour); the roles of sample annealing, disorder and shear band formation in the onset of yielding and failure; and, most importantly from a practical viewpoint, whether any impending catastrophic failure can be anticipated before it happens. We address these questions by studying the yielding of slowly sheared athermal amorphous materials, within a minimal mesoscopic lattice elastoplastic model. Our contributions are fourfold. First, we elucidate whether yielding will be ductile or brittle, for any given level of sample annealing. Second, we show that yielding comprises two distinct stages: a pre-failure stage, in which small levels of strain heterogeneity slowly accumulate, followed by a catastrophic brittle failure event, in which a crack quickly propagates across the sample via a cooperating line of plastic events. Third, we provide an expression for the slowly growing level of strain heterogeneity in the pre-failure stage, expressed in terms of the macroscopic stress-strain curve and the sample size, and in excellent agreement with our simulation results. Fourth, we elucidate the basic mechanism via which a crack then nucleates and provide an approximate expression for the probability distribution of shear strains at which failure occurs, as determined by the disorder inherent in the sample, expressed in terms of a single annealing parameter, and the system size.

An integrated benefit-risk assessment of cobalt-containing alloys used in medical devices: Implications for regulatory requirements in the European Union

In 2017, the European Union (EU) Committee for Risk Assessment (RAC) recommended the classification of metallic cobalt (Co) as Category 1B with respect to its carcinogenic and reproductive hazard potential and Category 2 for mutagenicity but did not evaluate the relevance of these classifications for patients exposed to Co-containing alloys (CoCA) used in medical devices. CoCA are inherently different materials from Co metal from a toxicological perspective and thus require a separate assessment. CoCA are biocompatible materials with a unique combination of properties including strength, durability, and a long history of safe use that make them uniquely suited for use in a wide-range of medical devices. Assessments were performed on relevant preclinical and clinical carcinogenicity and reproductive toxicity data for Co and CoCA to meet the requirements under the EU Medical Device Regulation triggered by the ECHA re-classification (adopted in October 2019 under the 14th Adaptation to Technical Progress to CLP) and to address their relevance to patient safety. The objective of this review is to present an integrated overview of these assessments, a benefit-risk assessment and an examination of potential alternative materials. The data support the conclusion that the exposure to CoCA in medical devices via clinically relevant routes does not represent a hazard for carcinogenicity or reproductive toxicity. Additionally, the risk for the adverse effects that are known to occur with elevated Co concentrations (e.g., cardiomyopathy) are very low for CoCA implant devices (infrequent reports often reflecting a unique catastrophic failure event out of millions of patients) and negligible for CoCA non-implant devices (not measurable/no case reports). In conclusion, the favorable benefit-risk profile also in relation to possible alternatives presented herein strongly support continued use of CoCA in medical devices.

Facile and Effective Positive Temperature Coefficient (PTC) Layer for Safer Lithium-Ion Batteries

With the popularization of lithium-ion battery propelled electric vehicles, the safety requirements of lithium-ion batteries are under immense scrutiny. Minimizing catastrophic cell failure events by developing improved safety features for lithium-ion batteries is an important endeavor. Herein, we report a novel, safe cathode configuration, achieved by sandwiching a positive temperature coefficient (PTC) material layer between the Al foil and active cathode material. The PTC layer (2–3 μm thick) was a composite of the carbon-coated LiFePO4(C-LFP), poly(vinylidene fluoride) (PVDF), and Super P. Due to the structural stability, good conductivity, and limited amount of C-LFP, the PTC layer maintained good structural integrity as a supporting layer between the Al current collector and active material layer. At high temperatures (>80 °C), the PTC effect was triggered in the protective layer by PVDF volume expansion, which effectively disrupted electron flow, leading to a dramatic increase in cathode resistance, thus preventing thermal runaway from occurring. Such a PTC layer-containing cell design not only shows outstanding safety performance during overheating scenarios but also has no degradation on cell performance. Furthermore, the PTC layer has good processability and is a convenient and practical material layer for commercial applications.

Non-monotonic precursory signals to multi-scale catastrophic failures

Identifying precursory trends in acoustic/seismic observations allows the forewarning/prediction of catastrophic events. However, rupturing across multiple scales leaves it unclear whether features of small events are applicable predictors of the larger ensemble final collapse. To resolve this issue, we present a multiscale heterogeneous model that straightforwardly characterizes the duration and mechanism of multiscale catastrophic failures. Our results identify four distinct classes of failure including random single breaks, small catastrophic failure (SCF) events, large catastrophic failure (LCF) events that consist of subordinate SCF and random break events, and a culminating macroscopic catastrophic failure (MCF) event resulting from the coalescence of subordinate LCF events. Only the local response quantities, recorded at their corresponding position, show an accelerating precursory trend to an SCF event. LCF events can appear in stages both before and after the maximum load in the system. Our findings highlight that although cumulative LCF event and deformation rates for the entire system always exhibit singular accelerating precursors as MCF is approached, this is not true at all individual event points. This may explain why no clearly accelerating precursor is observed before some catastrophic events. Thus, these results suggest a methodology for recognizing and distinguishing effective precursory information from monitoring signals across scales and in eliminating false predictions.

Meeting passivation requirements for spacecraft pressure vessels and fuel tanks

Most spacecraft have at least one pressurized vessel on board. In addition to a hole, it is possible that a pressure vessel may experience catastrophic failure (i.e., rupture) as a result of a hypervelocity impact. If a tank rupture were to occur on-orbit following a meteoroid or orbital debris particle impact, for example, not only could it lead to loss of life, but it would also generate a tremendous amount of debris that could compromise future space assets working in similar orbits. As a result, NASA and other space faring nations have put in place spacecraft design requirements to prevent additional sizable debris from being created in the event of pressure vessel rupture or catastrophic failure. In general, these requirements state that a spacecraft's stored energy devices are to be passivated at the end of a spacecraft's mission or useful life. Programs whose spacecraft designs are not able to comply with some aspects of those requirements employ an alternative, so-called “soft passivation” or “make safe”, option. This paper provides a summary of a project performed with the intent of providing some possible guidelines and considerations that can be used by satellite programs to help satisfy passivation requirements using a “soft passivation” approach, that is, when not able to perform complete, or “hard”, passivation, with specific regard to mitigating the threat posed by on-orbit meteoroid or orbital debris particle impacts.

Amorphization and Plasticity of Olivine During Low‐Temperature Micropillar Deformation Experiments

AbstractExperimentally quantifying the viscoplastic rheology of olivine at the high stresses and low temperatures of the shallow lithosphere is challenging due to olivine's propensity to deform by brittle mechanisms at these conditions. In this study, we use microscale uniaxial compression tests to investigate the rheology of an olivine single crystal at room pressure and temperature. Pillars with nominal diameters of 1.25 μm were prepared using a focused ion beam milling technique and were subjected to sustained axial stresses of several gigapascal. The majority of the pillars failed after dwell times ranging from several seconds to a few hours. However, several pillars exhibited clear evidence of plastic deformation without failure after 4–8 hr under load. The corresponding creep strain rates are estimated to be on the order of 10−6 to 10−7 s−1. The uniaxial stresses required to achieve this deformation (4.1–4.4 GPa) are in excellent agreement with complementary data obtained using nanoindentation techniques. Scanning transmission electron microscopy observations indicate that deformation occurred along amorphous shear bands within the deformed pillars. Electron energy loss spectroscopy measurements revealed that the bands are enriched in Fe and depleted in Mg. We propose that inhomogeneities in the cation distribution in olivine concentrate stress and promote the amorphization of the Fe‐rich regions. The time dependence of catastrophic failure events suggests that the amorphous bands must grow to some critical length scale to generate an unstable defect, such as a shear crack.

Emerging Issues and Methodologies for Resilient and Robust Water Distribution Systems

This editorial summarizes the 11 papers published in the Special Issue entitled “Resilient and Robust Water Distribution Systems: State-of-the-Art and Research Challenges” which were classified into five themes related to water distribution systems (WDSs): (1) state-of-the-art review on WDS resilience and robustness (ROB), (2) WDS performance quantification and recovery under earthquakes, (3) criticality analysis and visualization, (4) novel design methodologies, and (5) hydraulic parameter monitoring for WDS rapidity improvement. Following the provision of the number of views and citations of each paper in a brief manner, a paper in category (1) that reviewed recent studies on WDS robustness is summarized. Category (2) covers three papers on improving the WDS capacity to fulfil customers’ demands in the case of an earthquake, a representative catastrophic failure event, while category (3) includes papers on visualization methods to represent the system’s criticality. The studies included in themes (4) and (5) proposed novel design methods and monitoring approaches for improving WDS resilience, respectively. Contributions from each study are described in the context of WDS resilience. We hope that this Special Issue can (1) serve as a reference point from which readers review progress, recent trends, and emerging issues, and (2) shed light on the appropriate future directions of WDS resilience studies.

Time-Dependent Reliability and Redundancy of Corroded Prestressed Concrete Bridges at Material, Component, and System Levels

Due to structural deterioration, the performance of concrete bridges degrades with time and may result in catastrophic failure events, especially for nonredundant structures. This paper develops a methodology for assessing time-variant reliability and redundancy of multigirder prestressed concrete bridges at material, component, and system levels. Nonlinear analysis was performed to obtain the constitutive relationship of reinforced sections and girder components in which the adverse effects of reinforcement corrosion on structural capacity and ductility are considered. Subsequently, the nonlinear finite-element analysis was conducted to capture the time-dependent probabilistic resistance of the bridge system, considering different failure criteria (e.g., serviceability and ultimate limit states). Given the component- and system-level performance indicator, structural capacity-, reliability- and risk-informed redundancy was assessed. The feasibility and capability of the proposed approach were illustrated using an existing prestressed concrete bridge. The results demonstrate that the integrated damage mechanism between different levels has a significant effect on the structural ultimate capacity, reliability, and redundancy of corroded structures.

Robustness and Water Distribution System: State-of-the-Art Review

The resilience of a water distribution system (WDS) is defined as its ability to prepare, respond to, and recover from a catastrophic failure event such as an earthquake or intentional contamination. Robustness (ROB), one of the components of resilience, is the ability to maintain functionality to meet customer demands. Recently, the traditional probability-based system performance perspective has begun to shift toward the ROB and system performance variation point of view. This paper provides a state-of-the-art review of WDS ROB-based approaches proposed in three research categories: Design, operation, and management. While few pioneering works have been published in the latter two areas, an ROB indicator was proposed and thoroughly investigated for WDS design. Then, some future works are recommended in each of the three domains to promote developments in WDS ROB. Finally, a brief summary of this paper is presented, from which the final conclusions of the state-of-the-art review and recommendations are drawn. The new paradigm of WDS ROB-based design, operation, and management is in its infant stage and should be carved out in future studies.

Effect of Mechanical Stress Factors on Large Format Li-Ion Cell Thermal Runaway Characteristics

Expansion and contraction of Li-ion cell electrodes during cycling is known to exert mechanical stress and strain within cell components. During cell charge, Li-ion intercalation into the graphite anode structure increases anode swelling and thickness. Upon cell discharge, Li-ions de-intercalate from the carbon anode structure causing cell-level relaxation and a proportional reduction in cell swelling. Li-ion cell swelling has been shown to be a function of cell discharge rate, state-of-charge (SoC), and age. The impact of mechanical stress-strain swelling on Li-ion cells creates high contact pressure between electrode layers, degrades conductive carbon particle contact resistance, and irreversibly deforms the cell case structure. Mechanical stress loading also causes fatigue within internal cell components leading to an increase in cell impedance and capacity loss which may reduce cell cycle life performance. Li-ion battery (LIB) manufacturers have long recognized that the effects of cell-stack level stress fatigue on battery module architectures must be considered in LIB packaging designs requiring long cycle life performance. In LIB designs utilizing prismatic or elliptical-cylindrical cell geometries, cells are commonly packaged into modules by restraining the module stack by compression loading. In this manner, the adverse effects of cell stack deformation during charge-discharge cycling can be mitigated. In space applications, compression loading of cell modules also enables LIB’s to survive launch vehicle shock and vibration environments at high SoC’s. More importantly, mechanical abuse of LIB’s can result in an energetic catastrophic failure event. At high SoC’s, the hazards of a LIB safety incident may include venting, smoke, and fire indicative of catastrophic thermal runaway. Recently, the NASA has investigated the severity and consequences of catastrophic thermal runaway of large format Li-ion cell-based LIBs for human space flight applications. Thermal runaway safety testing of certain space-qualified Li-ion cell designs has shown that there is a correlation between applied cell compression forces and thermal runaway severity. This work focuses on the relationship between compression force and SoC on large format Li-ion cells qualified for human space flight applications. Empirical results from simulated internal short circuit trigger testing designed to induce catastrophic thermal runaway will be discussed.

Safety First

Safety First

Multiple rock-slope failures from Mannen in Romsdal Valley, western Norway, revealed from Quaternary geological mapping and 10Be exposure dating

Oversteepened valley walls in western Norway have high recurrences of Holocene rock-slope failure activity causing significant risk to communities and infrastructure. Deposits from six to nine catastrophic rock-slope failure (CRSF) events are preserved at the base of the Mannen rock-slope instability in the Romsdal Valley, western Norway. The timing of these CRSF events was determined by terrestrial cosmogenic nuclide dating and relative chronology due to mapping Quaternary deposits. The stratigraphical chronology indicates that three of the CRSF events occurred between 12 and 10 ka, during regional deglaciation. Congruent with previous investigations, these events are attributed to the debuttressing effect experienced by steep slopes following deglaciation, during a period of paraglacial relaxation. The remaining three to six CRSF events cluster at 4.9 ± 0.6 ka (based on 10 cosmogenic 10Be samples from boulders). CRSF events during this later period are ascribed to climatic changes at the end of the Holocene thermal optimum, including increased precipitation rates, high air temperatures and the associated degradation of permafrost in rock-slope faces. Geomorphological mapping and sedimentological analyses further permit the contextualisation of these deposits within the overall sequence of post-glacial fjord-valley infilling. In the light of contemporary climate change, the relationship between CRSF frequency, precipitation, air temperature and permafrost degradation may be of interest to others working or operating in comparable settings.

Heterogeneity: The key to failure forecasting.

Elastic waves are generated when brittle materials are subjected to increasing strain. Their number and energy increase non-linearly, ending in a system-sized catastrophic failure event. Accelerating rates of geophysical signals (e.g., seismicity and deformation) preceding large-scale dynamic failure can serve as proxies for damage accumulation in the Failure Forecast Method (FFM). Here we test the hypothesis that the style and mechanisms of deformation, and the accuracy of the FFM, are both tightly controlled by the degree of microstructural heterogeneity of the material under stress. We generate a suite of synthetic samples with variable heterogeneity, controlled by the gas volume fraction. We experimentally demonstrate that the accuracy of failure prediction increases drastically with the degree of material heterogeneity. These results have significant implications in a broad range of material-based disciplines for which failure forecasting is of central importance. In particular, the FFM has been used with only variable success to forecast failure scenarios both in the field (volcanic eruptions and landslides) and in the laboratory (rock and magma failure). Our results show that this variability may be explained, and the reliability and accuracy of forecast quantified significantly improved, by accounting for material heterogeneity as a first-order control on forecasting power.

Investigating Failure of Li-Ion Batteries Using in Operando Electrochemical-Acoustic Time-of-Flight Analysis

Electrochemical-Acoustic Time-of-Flight (EAToF) analysis takes advantage of the fact that in all closed electrochemical energy storage systems, regardless of the reaction mechanism (intercalation, dissolution/reprecipitation, phase change, etc.) the density and elastic modulus of each electrode changes as a function of its state of charge (SOC). This, in turn, affects how sound waves behave as they travel through the cell. Additionally, as a battery is cycled, progressive formation/degradation of critical surface layers, mechanical degradation of electrodes, consumption of electrolyte, etc. also affect the behavior of acoustic waves passing through the cell. Thus, the distributions of density and modulus within the cell as well as the rates of change of these distributions (and the resulting effect on the acoustic echoing behavior) can act as a fingerprint for the state of health (SOH) of the cell. In a previous study, we have demonstrated this in operando EAToF analysis experimentally using ultrasonic pulses during normal cycling of a wide variety of battery chemistries and form factors. Here, we focus on the effect of long-term cycling on the electrochemical-acoustic fingerprints, particularly for commercially-available Li-ion 18650 type cells. We examine how the EAToF patterns evolve as a function of depth of discharge and cycling rate, and also investigate the effect of “abusive” cycling conditions (e.g., elevated temperatures, over-charge/discharge, etc. as prescribed by UN 38.3 and IEC 62133 standards) on acoustic behavior. Two failure modes that we study in detail are electrolyte consumption and lithium plating in Li-ion batteries, and we verify failure modes with post-mortem analysis. Our results show that the fingerprints from EAToF analysis, perhaps in combination with various numerical analysis methods, can be correlated not only to SOC during normal cycling, but also to SOH during extended cycling and catastrophic failure events.

Multi-site data distribution for disaster recovery—A planning framework

In this paper, we present DDP-DR: a Data Distribution Planner for Disaster Recovery. DDP-DR provides an optimal way of backing-up critical business data into data centers (DCs) across several Geographic locations. DDP-DR provides a plan for replication of backup data across potentially large number of data centers so that (i) the client data is recoverable in the event of catastrophic failure at one or more data centers (disaster recovery) and, (ii) the client data is replicated and distributed in an optimal way taking into consideration major business criteria such as cost of storage, protection level against site failures, and other business and operational parameters like recovery point objective (RPO), and recovery time objective (RTO). The planner uses Erasure Coding (EC) to divide and codify data chunks into fragments and distribute the fragments across DR sites or storage zones so that failure of one or more site / zone can be tolerated and data can be regenerated. We describe data distribution planning approaches for both single customer and multiple customer scenarios.