Failure Of Theory Research Articles

Formal Analysis of Multiple-Cell Upset Failure Based on Common Cause Failure Theory

As an important component of space electronic systems, static random-access memory based field programmable gate arrays (FPGAs) are inevitably affected by single-event upsets, including single-cell upset (SCU) and multiple-cell upset (MCU), caused by space radiation. In particular, as the technology scales down, the probability of MCU increases significantly; however, the analysis of MCU remains an open challenge. Based on the common cause failure theory and continuous-time Markov chain, this article proposes a new hybrid model to quantify the coexistence effect of MCU and SCU on mitigation design modes with different combinations of strategies, such as triple modular redundancy, partition, and scrubbing. Synchronization and interleaving modeling technologies are used to construct the concurrent behavior of an FPGA system under different mitigation strategies and MCU problems. In addition, we introduce a partition factor to quantitatively explain the phenomena and laws of MCUs acting on adjacent partitions. The proposed method is demonstrated using TMR with scrubbing and partition strategies, which verify that the existence of MCU reduces the system reliability and availability, and the scrubbing and partition strategy are effective against MCU issues. More importantly, the limitations of mitigation strategies in different occurrence probabilities of MCU can be found by the proposed method. In summary, the analysis and discussion presented in this article can provide useful insights for relevant designers to select and optimize different design patterns of a system operating in a dynamic and complex radiation environment.

Design Optimization of Composite Submarine Pressure Hull

The design of composite submarine pressure hull is optimize the Stress and Failure index into consideration using ANSYS Software and Tsai-Wu Failure theory. The FEA value is compared with theoretical results. The composite of EPOXY resin and E-GLASS fiber is used to optimize the failure criteria by using ANSYS software. The failure index o the isentropic and orthotropic material should be less than 1 as per the Tsai-Wu criteria. The pressure hull is used to many structural applications such that Pressure Vessels, Aircrafts and Nuclear Submarines. The Failure index value is vary from applied load.

Experimental and numerical study on stiffness and damage of glass/epoxy biaxial weft-knitted reinforced composites

This paper deals with investigating the tensile characteristics of biaxial weft-knitted reinforced composites in terms of stiffness, strength and failure mechanism. The biaxial weft-knitted fabric was produced on an electronic flat knitting machine by E-glass yarns and then was impregnated with epoxy resin. Using an accurate geometrical model, the composite unit cell was designed in Abaqus software’s environment. Tensile tests were simulated in different directions on the created unit cell and the stiffness was calculated. By applying the proper failure theories, the composite strength was predicted and then critical regions of the unit cell were determined. In the next step, a micromechanical approach was also applied to estimate the same tensile features. Failure theories were also applied to predict the strength and most susceptible areas for failure phenomenon in the composite unit cell. The tensile properties of the produced composites were measured and compared with outputs of the finite element and micromechanical approaches. The results showed that the meso-scale finite element analysis approach can well predict the composite strength. In contrast, the meso-scale analytical equation model was not able to predict it acceptably because this model ignores the strain concentration. Both meso-scale finite element analysis and meso-scale analytical equation approaches predicted the similar locations for the composite failure in wale and course directions.

Failure Procedure in Epoxy Adhesive Joining Composite Plates

In this paper, several numerical simulations are performed to study the failure of epoxy adhesive joining composite plates. Different geometries for the joint and its edge are considered, and the effects of these geometries on the failure load are investigated. Moreover, the joints are subjected to different types of loading in order to determine the failure load. The failure theories of composite materials are implemented into the finite element software ABAQUS, and the failure propagation in the joint is studied.

SMALL ARMS AND LIGHT WEAPONS PROLIFERATION: IMPLICATIONS FOR SECURITY AND SUSTAINABLE DEVELOPMENT IN NIGERIA

Throughout the world, violence, delinquency and fear undermine the basic right of individuals to live in peace and fully benefit from the healthy and sustainable commu-nity. More worrisome is the seemingly uncontrollable proliferations of small and light weapons which remained one of the major challenges for security and sustainable development in Nigeria. It is against this backdrop that this study examines the threats that small arms and light weapons proliferation portends on the Nigerian security and sustainable development. They study relied on secondary data and utilizes the content analysis for interpretation of data. This study is anchored on the state failure theory to underscore situations that warrant recourse to small arms and light weapons. The study concludes that the debilitating economy, failure of the state to provide the basic necessities of life, corruption, high rate of youth unemployment and sluggishness among the state’s instrument of force viz: the Army, police etc., are some of the major factors that serve as challenges to meaningful efforts and policies at combating the menace in the country. This study therefore recommends among others that the gov-ernment in all levels should embark on poverty alleviation programs and provide em-ployment opportunities to unemployed youths. This will discourage youths from join-ing ethnic militias and other militant groups that pose threats to peace and security in Nigeria.

Review of the Book “Teoria esecului. Esecul ca forma de manifestare pozitiva a diferentei. Argumente pentru o etica a intervalului” [Failure theory. Failure as a form of positive manifestation of difference. Arguments for an ethics of the interval], autho

Failure theory is really important, as it is applicable in everyday life. Failure theory is approached from the perspective of George Constantin the volume entitled "Failure theory: Failure as a form of positive manifestation of difference. Arguments for an ethics of the interval ”, a volume that was published by Lumen Publishing House from Iasi, Romania, in 2018. Of course we avoid failure, because we are a society that seeks success and because we are a society that is afraid of difference. It is precisely these things that George Constantin calls upon us to talk about: about failure as a positive value or as a form of difference, about failure as an inherent positivity, because as long as all things move in the same direction, nothing will really change. When we talk about success, especially in the postmodern society, we speak first of all of uniformity, because despite the appetite for individual autonomy, the postmodern society, being a consumerist one, is, in principle a mass society. All the more difference is needed as a failure to these uniformities, precisely as a deconstruction of uniformity. Failure is a deconstruction of illusory success that occurs as a result of originality and stepping out of the interval.

FSI-based structural optimization of thin bladed composite propellers

Lamination of thin bladed composite marine propellers necessitates dropping layers following thickness variation to produce lighter propeller with good elastic damping. Composite blade is subjected to multiaxial loads resulted from nonuniformly distributed hydrodynamic pressure that cause the blade to undergo combined structural response of bent and twist therefore, strength evaluation of such tapered laminate is a highly nontrivial process that include significant fluid–structure interaction (FSI). This research aims to investigate the strength of composite propeller using unconstrained stacking-sequence optimization based on fully coupled CFD-FEA analysis. Different hub idealization techniques were studied to determine the most accurate treatment in predicting stress and deformation of the blade. Composite model configured for propeller VP1304 after modification on blade thickness and, initial analysis on balanced-stacking of [0, 90, 45,−45] were set as a benchmark for optimization process targeting to minimize failure index; calculated according to Puck failure theory considering fiber and matrix failure as well as delamination. Delamination is evidenced to be utmost critical mode of failure whereas, the optimization resulted in an optimum laminate with unbalanced nonsystematic stacking that succeeded to; reduce interlaminar stresses, avoid failure and, reduce maximum value of IRF (Inverse Reserve Factor) by 50% compared to the predefined balanced-stacking benchmark.

Failure modeling and analysis of composite laminates: Interval-based approaches

Composite materials inherently exhibit scatter in their basic characteristics such as the mechanical properties of constituent materials, fibers orientations, ply thicknesses, and applied loads. The uncertainties present in the basic parameters are available, in most cases, in the form of ranges or intervals. The use of the existing deterministic failure theories, which do not consider the observed variabilities in the input parameters, leads to poor failure assessment of composite materials. Several probabilistic failure models have been proposed in the past few decades. However, the probabilistic methods require a knowledge of the probability distributions of the basic variables which are not available in most practical systems. This work, for the first time, presents an interval-based failure analysis of composite materials using the truncation-based interval analysis and the universal gray system theory. These methods require only the lower and upper bounds of the uncertain parameters which are available in most practical systems. The application of the proposed interval-based failure models is demonstrated by considering two types of graphite/epoxy laminates: [0/±45/90] S and [0/90]2. This work shows that more realistic and meaningful failure assessment can be made using the universal gray system theory and the truncation-based interval analysis compared to the deterministic failure analysis.

Understanding Long-Term Policy Failures in Shrinking Municipalities: Examples From Water Management System in Sweden

Depopulation is a major drawback for local government when it comes to managing technical infrastructure. In water and wastewater systems management, overcapacity is not only a problem in economic terms. In addition, it brings with it serious technical problems and can also cause health problems for residents. In the context of Sweden, previous studies have recognised that shrinking municipalities fail to plan for or to maintain their fixed assets adequately, despite clear goals and guidelines stating that each generation should pay its legitimate share of what municipal operations cost. Despite these clear policy goals, many shrinking municipalities in Sweden have not prioritised the maintenance of fixed assets in water and wastewater. We know that these problems exist, but we know little about what lies behind them. This paper seeks to address this knowledge gap. By drawing upon theories of failure in public policy and administration and a case study of the municipality of Laxå, this paper seeks to arrive at a deeper understanding of policy failures in water systems management in shrinking municipalities in Sweden. The paper discusses three interrelated research questions: (a) What kind of failure are we dealing with here; (b) What organizational behaviours preceded the policy failure itself; and (c) What are the conditions that precipitated the observed failure(s)?

The Perceived Differences: The Sector Stereotype of Social Service Providers

What difference does “nonprofitness” make is a fundamental question for nonprofit research. Although being held as the basic assumption of the contract failure theory, the sector difference perceived by individuals remains as an open question for multiple methodological problems. Here, we present evidence from three experiments for further empirical exploration of the perceived sector difference with improved research design. Our findings suggest a general pattern of sector stereotype: people perceive nonprofits as being warmer and slightly more competent than for-profits. More importantly, we show that such stereotypical understanding mainly results from people’s repugnance against profit-seeking intention instead of preferences toward nonprofits in the social service market. Such pattern differs slightly across three subareas being tested. Finally, we find more relevant information about the organization serves as a potential moderator that weakens the effect of being a nonprofit, which blurs the sector boundary in a given market.

Study on Creep Failure of Powder Metallurgy

Based on the damage theory of Kachanov-Rabotnov, this paper studies the metallurgical materials with inclusions by numerical calculation. The results suggest that the creep failure theory is suitable for the analysis of the fatigue creep interaction behavior of powder metallurgy, and the creep failure is obviously related with the number of fatigue cycles.

A simplified approach in determining the c and φ for asphalt mixtures

In this study, using the Mohr-Coulomb failure theory, a simplified method was proposed to determine the cohesion (c) and internal friction angle (φ) for asphalt mixtures based on direct tension (DT) strength and indirect tension (IDT) strength or unconfined compressive strength (UCS) and IDT strength. The direct tension (DT) strength, superpave indirect tension (IDT) strength and unconfined compressive strength (UCS) were conducted to verify this method using three asphalt mixtures. It was found that the determination of c and φ values have mean absolute errors of 5.2% and 1.8%, respectively in comparing two methods indicating that the c and φ can be estimated from DT strength and IDT strength or IDT strength and UCS. Further study is recommended to verify using different binder grades and mixture types.

Reliability Analysis of Common Cause Failure Multistate System Based on CUGF

This paper addresses the problem of mixed uncertainty in the reliability analysis of multistate systems under common cause failure conditions. Combining the cloud model theory, universal generation function (UGF) method, and common cause failure theory, the universal generation function method is extended based on a probabilistic cloud model, i.e., the cloud universal generation function (CUGF) analysis method. The cloud model represents the random and cognitive uncertainty of the state probability, i.e., mixed uncertainty. Next, through CUGF, according to the calculation rules of cloud operators, we provide steps to obtain the reliability of a multistate system under independent failure and common cause failure conditions and obtain cloud digital features for reliability. The accuracy and feasibility of the method are verified by a numerical example. This paper solves the problem of reliability analysis of multistate systems with mixed uncertainty in unit state probability information under common cause failure conditions. We integrate system multistate, information uncertainty, and common cause failure for reliability analysis to avoid large errors, more in line with a project’s actual situation. We propose new ideas and methods to process randomness and fuzzy information or data in multistate system reliability analysis.

A multi phase-field fracture model for long fiber reinforced composites based on the Puck theory of failure

Phase-Field (PF) methods of fracture have emerged as powerful modeling tools for triggering fracture events in solids. These numerical techniques efficiently alleviate mesh dependent pathologies and are very suitable for characterizing brittle as well as quasi-brittle fracture in a wide range of engineering materials and structures including fiber reinforced composites. In this work, a multi phase-field model relying on the Puck’s failure theory is proposed for triggering intra-laminar cracking in long fiber reinforced composites. The current formulation encompasses the differentiation of fiber and inter-fiber (matrix-dominated) failure phenomena via the consideration of two independent phase-field damage-like variables, and the corresponding evolution equations and length scales. Moreover, for matrix-dominated deformation states, the present formulations endow the incorporation of plastic effects via an invariant-based plasticity model. Special attention is also devoted to its finite element implementation, which is conducted using the user-defined capabilities UMAT and UEL of ABAQUS, in conjunction with the thorough assessment of its thermodynamic consistency. Several representative applications pinpoint the applicability of the proposed computational tool.

Explanations of anisotropic strength and fabric evolution in granular soils by DEM simulations and buckling failure theory

ABSTRACT This research aims to discover a micro explanation of anisotropic strength of granular soils caused by different inherent fabrics based on the discrete element method (DEM) simulations. Soil particles are simulated as ellipsoids (i.e., clumped spheres) to preserve the elongation distributions of real soil particles that are determined by analysing 90,000 particles from 18 sands. Then, virtual soil specimens are prepared at 12 different inherent fabrics by restricting the particle long axis orientations. For each inherent fabric, triaxial tests are simulated at five intermediate stress ratio values, resulting in a total of 60 DEM simulations. The relationships between anisotropic shear strength and fabric evolution are investigated based on simulation results. For a specific inherent fabric, Lade’s isotropic failure theory can be used to describe shear strengths and octahedral contact normal fabric factors at peak and critical states. A buckling failure theory from structural engineering is introduced to explain the anisotropic strength of granular soils and fabric evaluations observed in laboratory tests and simulations. As the angle between loading and fabric direction increases from zero to 90 degrees, the conceptual widths of soil columns decrease, leading to the smaller buckling failure loads and therefore the smaller shear strength of granular soils.

Feasibility of Wearable Sensing for In-Home Finger Rehabilitation Early After Stroke.

Wearable grip sensing shows potential for hand rehabilitation, but few studies have studied feasibility early after stroke. Here, we studied a wearable grip sensor integrated with a musical computer game (MusicGlove). Among the stroke patients admitted to a hospital without limiting complications, 13% had adequate hand function for system use. Eleven subjects used MusicGlove at home over three weeks with a goal of nine hours of use. On average they achieved 4.1 ± 3.2 (SD) hours of use and completed 8627 ± 7500 grips, an amount comparable to users in the chronic phase of stroke measured in a previous study. The rank-order usage data were well fit by distributions that arise in machine failure theory. Users operated the game at high success levels, achieving note-hitting success >75% for 84% of the 1061 songs played. They changed game parameters infrequently (31% of songs), but in a way that logically modulated challenge, consistent with the Challenge Point Hypothesis from motor learning. Thus, a therapy based on wearable grip sensing was feasible for home rehabilitation, but only for a fraction of subacute stroke subjects. Subjects made usage decisions consistent with theoretical models of machine failure and motor learning.

Probabilistic method for evaluating the permanent strain of unbound granular materials under cyclic traffic loading

In this study, a series of large-scale cyclic triaxial tests with different water contents (w), confining pressures (σ3), and dynamic deviatoric stresses (σd) is performed to investigate the accumulative permanent strain (εp) behavior of an unbound granular material (UGM) used in the construction of railway subgrade beds. Results indicate that an increase in confining pressure effectively inhibits the development rate of εp, and the εp behavior of stable specimens can be categorized into an initial rapidly increasing stage and a subsequent gradual stabilization stage, with different causes of material strain at each stage. The permanent strain accumulated from the first loading cycle, i.e., the model parameter a, demonstrates a power function relationship with the dynamic-static deviatoric stress ratio (η), and the model parameter b, which implies the increasing rate of εp, is strongly correlated with η and w. A probabilistic method based on a semi-logarithmic prediction model and probabilistic failure theory is proposed to evaluate the development range of εp of UGMs while considering the effects of the confining pressure, dynamic deviatoric stress, static failure deviatoric stress, and water content. Applications of the proposed method indicate that the developed probabilistic model can yield acceptable εp predictions of UGMs.

The influence of material shear nonlinearity on predictive failure envelopes of multidirectional laminates

In present study, laminates with the type of [±θ°]S and [0°2/±θ°]S are investigated in order to clearly show the effect of material shear nonlinearity, and then theoretical predictions are compared with experimental data. In the whole process of generating failure envelopes, secant shear modulus instead of initial shear modulus is used for accurate shear stress-strain relation. The modulus values are recalculated every time when the combining load is changed. Final failure envelopes are then compared between numerical models. It is found that the variation in the size of safe regions from nonlinear analysis is closely related to the way of combing load and fiber directions. So in the process of improving failure theories or in the applications of failure theories, the effect of material nonlinearity can be considered appropriately.

I Still Suck at Everything: The Generality of Failure and Future Arrest

ABSTRACT The generality of failure theory links arrest – a “failure” at crime – to other failures later on in life such as getting a sexually transmitted disease or losing a job. Yet, this theoretical orientation also suggests the opposite may be true. Early life failures such as failing a class in school and becoming an underage parent may be a marker of an individual likely to fail at crime later in life. We test this theory using eleven waves of data from the Pathways to Desistance survey. Findings demonstrate that both personal failures (e.g., becoming an underage parent, failing a class) and public failures (e.g., being fired from a job, suspended from school) early in life are significantly associated with failing at crime later in life. Results persist even after accounting for a wide range of potential confounding factors such as criminal offending, illicit substance use, IQ, and self-control. Findings highlight the utility of the generality of failure theory in understanding deviant behavior.

Identifying key sectors based on cascading effect along paths in the embodied CO2 emission flow network in Beijing-Tianjin-Hebei region, China.

The emission of carbon dioxide (CO2) is a serious environmental issue, especially in Beijing-Tianjin-Hebei region. Unlike previous studies that mainly consider the bilateral and direct connection between two sectors, this study identifies path-based key sectors by considering the cascading effect of a sector on other sectors on paths of the entire economic system. We first construct an embodied CO2 emission flow network of Beijing-Tianjin-Hebei region, combining environmental input-output analysis and complex network theory. Then, the path-based key sectors are identified by traversing the path of each sector in the network based on cascading failure theory and hypothesis extraction method. On the one hand, the results show that a small number of sectors shoulder a large proportion of the embodied CO2 emission flows from both path and sector perspectives. On the other hand, we identify some path-based key sectors that did not receive enough attention from the sector perspective. Additionally, the sum of the embodied CO2 emission flows in about 30 steps accounts for 90% of the total embodied CO2 emission flows on its supply chain path. To more effectively reduce carbon emission, sectors that connect these 30 steps should be concerned in some policy recommendations. The method proposed in this paper can complement existing methods and contribute to further reducing CO2 emissions in the Beijing-Tianjin-Hebei region.