Kind Of Failure Research Articles

Explicit and implicit Valuation-Based System methods for the risk assessment of systems subject to common-cause failures under uncertainty

Multiple components within a system may fail or malfunction simultaneously due to a shared cause or common cause (CC). This kind of failure is referred to as a common-cause failure (CCF), and it contributes greatly to the system failure. Due to the insufficiency of relative data and system complexities, different kinds of uncertainties inevitably exist in real-world system modeling. This paper proposes explicit and implicit Valuation-Based System (VBS) methods to model systems subject to CCFs, and to evaluate the failure probability of such systems considering the parametric uncertainty related to state probabilities of components and the model uncertainty related to the system structure. Both methods are suitable to model systems subject to CCFs under different kinds of uncertainties, and allow the relationship among multiple CCs being s-independent, s-dependent or mutually exclusive. Finally, the proposed methods are applied to model hazardous material transportation accidents and to evaluate the occurrence probability of accidents using statistical data.

Analysis of Cylindricity Error of High and Low Temperature Storage Tested Alternator Stators

This paper investigates the internal shape correctness of alternator stators occurring in high and low temperature storage tests. This kind of failure can affect the adequate operation of alternators since vibrations can occur during rotation of the other part of the alternator, the rotor. This error can reduce the efficiency of the alternator. The aim of this study is to examine the influence of different testing parameters, such as the temperature and the running time of the test, and whether or not the stator is equipped with a damping element. For the experiments we used the full factorial experimental design method. The measurement of the cylindricity of the specimens was done with a circular and position error measuring machine. From the measured data, special improvement ratios can be calculated in order to define the appropriate range of testing parameters that resulting greater deformity. A further aim is to compare the different cylindricity parameters and the features of theirs measured values.

A new workflow for the effective distinction between necking induced spilts and direct fracture phenomena

The predominant mode of failure in stamping applications is still splitting due to localized necking. This kind of failure is very effectively captured by the forming limit curve, especially if nonlinear deformation effects are modelled. With the sharp increase in low-ductility (weight efficient) materials, direct fracture phenomena (surface cracks, edge cracks, shear cracks, etc.) increasingly enter the daily industrial stamping practice, especially in follow operations. Contrary to the classical FLC analysis, there exists nowadays no industry-wide standardization for characterizing these phenomena. This drives up modelling costs and reduces the expected improvement in the overall modelling uncertainty. It therefore becomes crucial to understand and detect the circumstances in which an advanced fracture characterization is necessary, such that limited resources can be effectively allocated. The present contribution aims to propose such a workflow. Firstly a reasonable lower bound for the fracture limits is estimated based on theoretical considerations and evidence from scientific literature. This estimation is used to conduct a first analysis step which is used to categorize the process based on whether a standard modelling approach is sufficient to deliver the required accuracy. A second step of accurate fracture identification is therefore only recommended for the subset of geometries with particularly high risk. The approach is tested on data for AA6016 and DP980 from literature and validated based on published experimental results.

Explicit and implicit Bayesian Network-based methods for the risk assessment of systems subject to probabilistic common-cause failures

In an engineering system, multiple components may fail simultaneously due to a shared cause or common cause (CC). This kind of failure is referred to as a common-cause failure (CCF), and it contributes greatly to system risk. However, the propagation of a cause condition to the affected components is not always certain (deterministic). The propagation may be probabilistic due to many reasons, such as system specific defences against cause condition propagation. This kind of CCF is also called the probabilistic CCF (PCCF) which is defined as any condition or event that causes multiple components to fail or malfunction simultaneously with different occurrence probabilities. A system subject to PCCFs is sometimes affected by multiple CCs. This paper proposes explicit and implicit Bayesian Network (BN)-based methods to model systems subject to PCCFs considering different relationships among multiple CCs within a single model. The originality of this work lies in the use of BN to model the probabilistic dependencies among multiple CCs under different relationships and their affected components. Both methods are suitable for systems in which multiple CCs affect different components with different dependencies. Finally, the proposed methods are applied to model the risk of gas explosion in coal mines to evaluate the occurrence probability of accidents.

Stability analysis of block-flexural toppling of rock blocks with round edges

One of the most conventional toppling instabilities is the block-flexural toppling failure that occurs in civil and mining engineering projects. In this kind of failure, some rock columns are broken due to tensile bending stresses, and the others are overturned due to their weights, and finally, all of the blocks topple together. A specific feature of spheroidal weathering is the rounding of the rock column edges. In the mode of flexural toppling failure, rounding of edges happens only at the upper corners of the block but in the block toppling failure mode, due to the presence of cross-joints at the base of the block, rounding of edges also occurs at the base of the block. In this work, a theoretical model is offered to block-flexural toppling failure regarding the erosion phenomenon. The suggested methodology is evaluated through a typical example and a case study. The results of this research work illustrate that in the stable slopes with rectangular prismatic blocks, where the safety factor value is close to one, the slope is subjected to failure due to erosion. Also the results obtained show that the recommended approach is conservative in analyzing the block-flexural toppling failure, and this approach can be applied to evaluate this failure.

A comparative sociopragmatic analysis of the dialogues in Turkish and Azerbaijani B1-B2 EFL textbooks

Different communities assess social distance, social power, rights and obligations, and degree of imposition used in specific speech acts differently. As a result of this difference, foreign language learners are likely to make sociopragmatic failure. This kind of failure is harder to correct because of the learners’ justifiable sensitivity in social (or political, religious, and moral) matters. Nevertheless, the research has proven the effectiveness of instruction on development of learners’ awareness of sociopragmatic aspects of language use. However, there is almost no investigation on the representation of sociopragmatic variables in second or foreign language textbooks. Considering that textbooks are essential for providing input for the learners in development of their sociopragmatic competence, we compared EFL textbooks designed for and employed in public schools of Turkey with those designed for and employed in public schools of Azerbaijan, to evaluate how sociopragmatic and related variables have been addressed in dialogues present in these textbooks. The results of the investigation revealed that there are some significant differences between Turkish and Azerbaijani textbooks regarding representation of speech acts, vertical distance, and strength of socially defined rights and obligations. These differences, on the other hand, can be accounted for by the inadequate representation of speech situations. By this study, we aspired to draw textbook writers’ attention to such inadequacies elimination of which may result in sociopragmatically more adequate textbooks, and attract second- or foreign language teachers and learners’ attention on the significance of sociopragmatic competence for appropriate language use.

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)?

Analysis of Corrosion Behavior on External Surface of 110S Tubing

The failure analysis of 110S tubing during acidizing process was addressed. Results showed that serious pitting corrosion occurred on the outer wall of tubing, and there was no obvious pitting on the inner wall. The maximum pitting depth on the outer wall was 1019 μm. According to the results of simulation corrosion test, needle-shaped pitting appeared on the sample surface in the test without inhibitor, the maximum depth of pitting was 158 μm; and no pitting was found on the sample surface in the test within 1.5% TG501 inhibitor; the original pitting were deepened after spent acid test, and the sample with no pitting at the beginning also showed deep pitting corrosion after 96 hours spent acid test. It was indicated that the spent acid accelerated the development of pitting significantly. The external surface corrosion of the 110S tubing was caused by the chemical reaction between the high-concentration acidifying liquid and the outer wall of the tubing. There is a gap between the tubing and coupling threaded connection, which caused the acid solution entered into the thread position, and hence the severe corrosion of the thread and pin end of the tubing happened, the joint strength was continuously reduced with corrosion development till the tripping of the coupling, and then the lower string dropped. Some suggestions were proposed for avoiding or slowing down this kind of failure based on this study.

Application of Failure Mode Effect Analysis for Improved Scheduling in Maintenance of Machines

Maintenance of machines is crucial measures in order to have stable and improved work flow. Any kind of failure might result in complete failure of the machine. Hence it becomes essential to identify the vulnerable failures that might occur in the components of any machine. The present work is carried out in order to improve the scheduling in maintenance of a lathe machine. Different components of the machine are studied in this research. “Failure mean effective analysis (FMEA)” method is applied to identify the failures associated with the components of the machine. Risk priority number is calculated based on which the components are provided with ranks. The rank signifies the flow of maintenance for all the components. The results reveal that the flexure bearing needs the least maintenance as it has the highest rank.

Assessing the stability of rock slopes with respect to flexural toppling failure using a limit equilibrium model and genetic algorithm

Abstract Flexural toppling is a common mode of instability of anti-dip bedding rock slopes. However, there is currently no theoretical method available for determining the failure surface associated with this kind of failure. In this work, a limit equilibrium model combined with a genetic algorithm (LEM-GA) method was proposed for predicting the safety factors and failure surfaces of rock slopes subject to flexural toppling failure. A MATLAB program was subsequently developed to implement the proposed method which takes the geometric and mechanical parameters of the slope as inputs and the safety factor and potential failure surface associated with the slope as outputs. Two test models were used to check the validity of the LEM-GA method. The correspondence between the calculated and experimental results is good which demonstrates the feasibility of using the LEM-GA method to predict the stability of this kind of slope. The LEM-GA method is also extended to investigate the effect of non-uniform joint spacing on slope stability. The results indicate that when an average joint spacing is used to assess the stability of a non-uniform slope, the predictions made are conservative and err on the safe side. The LEM-GA method proposed in this work offers a sound basis for evaluating the stability of anti-dip bedding rock slopes and improving their design.

Failures of interest

What kind of failure is it to lose interest and detach from a project, empirical scene, or cause? Should we always stay interested in our work and attempt to interest others? Through discussion of two ongoing but perhaps failed projects alongside reflection on various failures over my career, I explore the relationship between affects of failure and the event and relation of interest. Staying with the non-evental dynamics of the ordinary failures that accumulate in the background to all academic lives, I explore how losing interest or not holding interest relates to and expresses the attachments and detachments we have to academic life. Via these reflections, I argue that we should pay attention to those ordinary failures – like losing interest - that don't quite fit with institutionally named and collectively recognised events of failure – a rejected paper or grant, for example.

Effect of steel fiber on the shear transfer strength across a crack in reactive powder concrete

In structural concrete members that have geometrical discontinuities, the type of failure is called direct shear failure when there is no; the same member may change its response when the load arrangement is changed. This kind of failure is related to the cracks along the plane where the loaded member slides along the stationary support system and cracks are perpendicular to the axis of the member. Numerical analysis on push-off specimens were conducted in this study to investigate the shear strength in reactive powder concrete, which has cementitious compositions. The validation of the material and geometrical model to check the efficiency of the constitutive model to simulate the behavior of shear strength of RPC was achieved through comparison with the experimental result of previous work. The effects of volume fraction, aspect ratio, shape of steel fibers on the shear strength were considered to be the variables of the study. The data analyzed showed that the increase in volume fraction of steel fiber from 0% to 0.5% resulted in an increase in the shear strength of RPC by 40.3%, while, an increase in the volume fraction of steel fiber from 0% to 1.5% increased the shear strength of RPC by 140.3%. Using hook ended steel fiber increased the shear strength of RPC by 62.5%. Furthermore, the shear strength of RPC increased by 49.8% when the aspect ratio increased from 75 to 100. The stiffness and ductility of RPC members increased when the volume fraction, aspect ratio increased and provided shape of steel fiber.

A felületvasalás alakhelyességre és felületi mikro-keménységre gyakorolt hatásának vizsgálata

Jelen tanulmányban az élettartamnövelő felületszilárdító eljárások közé tartozó felületvasalás technológiájának vizsgálatával, bemutatásával, valamint ennek a megmunkálási módnak a hengerességre és felületi mikro-keménységre gyakorolt hatásának elemzésével foglalkozom 42CrMo4 jelölésű ötvözet esetén. Az egyes jellemzők méréséhez egy köralak- és helyzethiba mérő-, valamint egy Vickers keménységet meghatározó berendezést használtam fel annak bizonyítására, hogy a felületvasalás előnyösen alkalmazható ezen az anyagminőségen.

Seismic analysis of arc concrete dam with consideration of the rock fault

Nowadays, the safety of structures against natural disasters is of great importance, which is ranked depending on the type of the structure. Structures that cause the highest property damage and personal injury after the destruction are the ones that are more important in terms of safety. A dam is one of the structures with vitally important safety that should be taken into consideration. This is because it supplies water for domestic, agricultural, industrial, and community uses; hence, any kind of failure in this process would most likely cause loss of life and significant economic losses. Models designed in this article are based on Karun III dam. There is a total of 20 different models that compare the results of inserted stress and displacement, each of which is indicative of different kinds of fracture in the foundation under different records and elasticity modulus. In the state where Tabas earthquake is inserted into the model, the Young’s modulus ratio related to Jiang’s article and the fracture are on one-third of the left, and the highest amount of pressure is exerted on the dam body. In the state where Manjil earthquake is inserted into the model, the fracture takes place on the foundation at the bottom third and, as a result, the least amount of pressure is exerted at the dam body.

Termikusan tesztelt generátor állórészek hengerességének vizsgálata

A tanulmány a generátor állórészek belső alakhibájának vizsgálatával foglalkozik, melyet magas és alacsony hőmérsékleten való tesztelési eljárás idéz elő. Ez a fajta meghibásodás befolyásolhatja a generátorok megfelelő működését, mivel a generátor egy másik alkatrészének, a rotornak a forgása során rezgések léphetnek fel. Kijelenthető, hogy ennek a hibának a hatása csökkenti a generátor teljesítményét. A publikáció célja annak vizsgálata, hogy a különböző tesztelési paraméterek úgy, mint hőmérséklet, tesztelési idő, az állórész el van-e látva rezgéscsillapító gyűrűvel vagy sem, milyen hatással bírnak. A kísérlet megtervezéséhez és végrehajtásához a teljes faktoriális kísérlettervezés módszerét alkalmaztuk. Az egyes elemek hengerességének mérése Taylor Hobson Talyrond 365 gyártmányú köralak- és helyzethiba-mérőberendezésen valósult meg. A mért adatokból speciális viszonyszámokat alkottam, annak érdekében, hogy meghatározzam azt a paramétertartományt, mely a legnagyobb mértékű deformációt okozza.

Ultrastructural changes in hydatid cyst walls obtained from human cases, exposed to different therapeutic approaches.

Recurrence of cystic echinococcosis as a result of treatment failure is frequently reported to cause a major problem in management of such serious parasitic infection. The deeply seated innermost germinal layer of hydatid cysts is a relatively delicate layer, yet responsible for viability maintenance of this parasitic stage. In this study, a trial was done to explore the ultrastructural changes in germinal and laminated layer of the hydatid cyst for the first time in human cases exposed to different therapeutic approaches which were done earlier to the final open surgical intervention. Four groups were included: group 1 did not receive any earlier form of treatment; group 2 was previously treated with only medical therapy; group 3 was treated with a single course of medical treatment, plus a single PAIR technique; group 4 was treated with multiple courses of medical treatment plus multiple PAIR techniques. Complete alteration of ultrastructural features of germinal and laminated layers were observed only with samples from group 4, indicating a kind of failure of the therapeutic approaches used in group, 1, 2, and 3, unless repeated in group 4 to achieve a real change regarding the fitness of the parasitic cystic lesions. Searching for more effective, safe, therapeutic method is highly recommended which may end the suffering of the affected patients.

‘Did Not Finish’: A Phenomenology of Failure

ABSTRACT This paper explores what it means to fail in an ultramarathon—be marked DNF, or Did Not Finish—through hermeneutic phenomenology. In today’s popular culture, failure holds a paradoxical position: Particularly in the ‘startup’ ethos, failure is touted as a good, but only because it brings one closer to success. On a Heideggerian perspective, this is an inauthentic understanding of failure. This paper proposes that sport, and specifically ultrarunning, is a site for an authentic understanding of failure—and, consonantly, success. The notion of death is a major consideration: Though death is often described as a kind of failure, it is better understood phenomenologically as that which reveals and focuses one’s authentic possibilities for success. Failure, on the other hand, is a cutting-off of possibility. Three types of DNF can be discerned, corresponding to a cutting-off in the past, present and future, respectively. In ultrarunning, an athlete exists as being-toward-death, and finishing belongs to the athlete as part of their self and world. When a DNF happens, an athlete is suddenly rendered incomplete, worldless. This is a jarring, painful experience, from which it takes time and effort, and a reconstruction of self, to recover.

Electromechanical Simulation and Analysis of Displacement Failure of Input Shaft for Harmonic Drives

Axial displacement of the input shaft is one of the faults of harmonic drives in industrial robots. Aiming at finding a monitoring method of this kind of failure in this paper, the simulation of axial displacement failure is performed by establishing the electromechanical system model of the harmonic drive. The exponential LuGre friction model is used in the developed harmonic drive model, and an additional friction torque model caused by the axial displacement failure was established. The nominal load is input into the harmonic drive, and the simulation experiment was implemented with different degrees of input shaft axial displacement failure. The simulation result shows that the input shaft axial displacement failure of the harmonic drive affects the state (the internal current) of the drive motor. In the future, one can detect the axial displacement failure of the harmonic drives based on this finding.

Electric pole failure: A safety concern

A galvanized electric street lamp pole with expected life of 25 years, near a slag dumping area failed from its base after 5 years of service. The base was found to be severely corroded and pole completely covered by mud. Visual inspection revealed no pitting at the inner surface but thinning at the base. 200 μm zinc coating was absent at the fractured region but remained intact at the inner surface. Finite Element Analysis showed that the corroded pole with 1.5 mm thickness (measured in failed zone) would start failing due to high stress exceeding yield strength at a wind speed of 86 km/h, much lower than that prevalent confirming that the pole failed due to corrosion. The soil pH was 8.0–9.0 at which the zinc coating was stable. Resistivity and moisture content of the soil were measured to be 333 Ω and 56% respectively. In order to investigate soil corrosivity for buried structural materials the oxidation reduction potential was measured. At this combination of resistivity, moisture content and ORP the soil was highly corrosive. The decreased resistivity, possibly due to the presence of ions from condensed CO gas hanging and dripping just above the failed pole, enhanced flow of ions thereby making the soil electrolytic resulting in faster formation of Zn2+ ions. The pole thus failed from the base due to accumulation of mud creating an oxygen concentration cell at the interface. Tar based cathodic coating was recommended to combat oxygen concentration cell corrosion along with proper maintenance and mud removal in order to avoid such kind of failure.

Experimental study of high-strength steel under VHCF with external alternating magnetic field

The processes of formation “fish eye” structure is still an issue in scientific community. This interest initiated by active application of metal construction in technique behind the customary cyclic service life. This kind of failure is most dangerous in reason undersurface initiation and uncontrollable crack propagation. The posteriori structural analysis cannot give information on the kinetics of the critical defect evolution leading to the failure of the sample. The goal of the study is combination of posteriori investigation of tested samples and in-situ monitoring process using nondestructive technique.In this work the authors suggests the in-situ method for monitoring the fracture initiation and study kinetic of defect evolution based on analysis of magnetic field interaction with material. It is shown rapidly dynamic of registered signals on final stage of fatigue test.