Various Types Of Failure Research Articles

Optimization of dome shape for filament wound pressure vessels using data-driven evolutionary algorithms

ABSTRACT Filament wound glass/epoxy and carbon/epoxy pressure vessels were designed using a data-driven evolutionary approach along with a classical mechanics-based analysis. Analytical solutions for three known end domes (a spherical shell, a geodesic-isotensoid shell and a shell based on minimizing of the Tsai-Hill’s criterion) and end dome based on Hoffman’s criterion were used to create surrogate models through two different evolutionary optimization algorithms: Evolutionary Neural Net (EvoNN) and Bi-objective Genetic Programming (BioGP) and bi-objective evolutionary optimization studies were carried out using them. Composite pressure vessels are manufactured by means of filament (helical) winding. The stresses in the end domes were evaluated analytically and compared with each other. Hoffman strength criterion was chosen for the evaluation of the critical areas of the shells. Moreover, the best dome shape for given material and polar hole/equator ratio was selected for various types of failure.

An Experimental Study on Stabilization of Expansive Soil by Copper Slag

Abstract: Stability of any structure depends on strength properties of underground soil on which it is constructed. Structures basically transfer all the loads come on itself directly to the ground. If the underlying soil is not stable enough to support transferred loads then various types of failure occur such as settlement of the structure, cracks and so on. To solve this issue, soil improvement is necessary because it not only lowers the construction cost but also cuts the risk of any damage of structure later on. Numerous improvement methods can be adopted to make ordinary soil stable enough to support the structural loads. In this research work a number of tests may conduct using both ordinary soil and stabilised soil. The stabilising agents are using in this study is Copper Powder. The varying percentage of 5%, 10%, 15%, 20% and 25% added to the expansive soil. It binds the soil particles together and helps in reduction of rapid change in volumetric properties. The tests may conduct on un-stabilised and stabilised expansive soil is CBR, UCS and tri-axial test.The test may conducted on untreated and treated expansive soil i.e. index properties (liquid limit, plastic limit), compaction test, California bearing ratio (CBR), unconfined compressive test (UCS), Triaxial test

The Analytical and Numerical Stress Analysis of Various Domes for Composite Pressure Vessels

The paper describes analytical and numerical solutions for five selected domes (a spherical shell, a geodesicisotensoid shell, a shell with zero transversal strain, a shell with zero transversal stress, and a shell with identical strain) for composite pressure vessels manufactured by means of filament (helical) winding. The stresses and strains in the domes were evaluated analytically from known equations with the use of MATLAB script for numerical evaluation and via finite element analysis (FEA) with Abaqus software and results were compared with each other. Two failure criteria, interactive and non-interactive, were chosen for the evaluation of critical areas of the shells. Moreover, the best dome shape for a given material and polar hole/equator ratio was selected for various types of failure, i.e., a loss of tightness/leakage or the failure of the fibers.

Development of universal algorithm of voltage circuits detecting faults of microprocessor protection and automation devices

Reliability, along with response speed, sensitivity, and selectivity, is the key requirement for relay protection (RP) devices. The reliability of modern RP digital terminals is understood as protection operation for all estimated failure modes and failure of protection equipment to operate in all other modes, in which this protection is not provided. Analysis of the secondary voltage schemes and algorithms of detecting faults in these circuits reveals several disadvantages of the implementation of blocking in case of faults in voltage circuits. All existing algorithms and blocking schemes in case of faults in voltage circuits suffer from several disadvantages. In this regard, it is relevant to develop a universal relay protection terminal, which can be used with any types of voltage transformers. The MatLAB Simulink is used to simulate the primary failure of secondary circuits for the connection schemes of the voltage transformer load on phase and electric line voltages. The authors propose the algorithm that allows us to create a typical universal RP terminal, which can be used with any type of voltage transformers. To detect the neutral conductor interruption of the «star» circuits, it is proposed to create an artificial asymmetry at the input voltage circuits of the relay protection and automation (RPA) terminal and develop a group of fault detectors that analyze the position of the offset neutral on the voltage complex plane. Using a simulation model of various types of failure of voltage transformer secondary circuits and the logic diagram of the unit that implements the proposed algorithm, the authors graphically show that the detection of a break in the neutral wire is possible due to monitoring the zero-sequence voltage spike (triggering of the pulsed dU0 fault detector) with neutral displacement to the complex plane area, which is set by the setpoints. The results obtained allow us to implement a universal scheme of blocking faults in voltage circuits. This scheme does not depend on the voltage transformer secondary load connection method and exclude the disadvantages of existing solutions discussed in the article. This algorithm allows us to develop a typical universal RPA terminal. Due to its connection scheme and functional and logical implementation, this terminal can be used with any types of voltage transformer without reprogramming. Also, the proposed algorithm fully complies with the requirements of the current regulatory and legal documents.

Failure mechanisms and bending strength of Fuchsia magellanica var. gracilis stems

In the course of biological evolution, plant stems have evolved mechanical properties and an internal structure that makes them resistant to various types of failure. The mechanisms involved during damage development and failure in bending are complex and incompletely understood. The work presented builds on a theoretical framework outlined by Ennos and van Casteren, who applied engineering mechanics theory to explain why different woody stems fail in different ways. Our work has extended this approach, applying it to a detailed analysis of one particular species: Fuchsia magellanica var. gracilis. When subjected to three-point bending, stems of this species exhibited one of two failure mechanisms: a plastic hinge or a greenstick fracture. We developed a predictive model using a computer simulation and a mathematical analysis using the theory of plastic bending. Required material properties were obtained from tests, the literature and imaging techniques. We found that greenstick fractures are more likely to occur in more lignified stems with a higher density. We discovered a new failure mode: an internal crack caused by tensile transverse stress. This work helps in understanding how plants have evolved their bending resistance and may assist in the creation of novel engineering structures inspired by these principles.

Comparative political process theory

Abstract What, if anything, do recent constitutional court decisions requiring a legislature to create a customized presidential impeachment procedure, invalidating a government’s prorogation of parliament, rejecting the disbanding of an independent anticorruption unit, and striking down legislation for inadequate deliberation have in common? They are all examples of courts protecting the political processes of representative democracy against threats or failures. Yet none of these various types of failure appear in the work that is synonymous with a political process theory of judicial review: John Hart Ely’s Democracy and Distrust. This article argues that when we look beyond the United States and at the comparative context generally, a political process theory has a great deal of relevance and application to constitutional law and courts around the world, both descriptively and normatively. Especially now when the structures and processes of representative democracy are under assault in so many places. However, for comparative purposes, Ely’s account takes too narrow a view of what types of political process failures exist and are of concern, and what types of judicial review or other protective mechanisms they may call for. It is also an interpretive theory of one system, but what is needed in the comparative context is a broader, normative theory of the role of courts and other actors in protecting democratic politics. Accordingly, suitably expanded and adapted, a comparative political process theory can make a valuable contribution to the field of comparative constitutional law. This article seeks to explore and further develop such a theory.

UTILIZATION OF ANALYTICAL METHODS FOR THE FAILURE ANALYSIS OF INJECTION MOLDED PART

As the use of the thermoplastic materials becomes conventional in numerous parts and various applications, incidence of various types of failure becomes inevitable. Failure of injection molded parts can be a cause of economic and legal problems, as well as causing health damage or death. Public perception of plastics is adversely affected by their failures, such as the bad reputation that early plastics earned with toys that broke too easily. As the injection molding process is very complex, finding the cause of failure is very complicated. In industrial mass scale production, determining the cause of failure is key point in customer-supplier relationship. In the presented study, a type of injection molded product from HDPE affected by occurrence of cracks was investigated by mechanical, thermal testing and spectral analysis. Mechanical properties were evaluated by the uniaxial tensile test and the SHORE hardness test. Thermal properties of the samples were evaluated by DSC/TGA analysis and for the spectral analysis a Raman spectroscopy device was used. Obtained results provided information about fluctuating quality of used material, coupled with non/stable molding conditions and small molding window. All those aspects caused molded in stress, which was released in the form of crack during the installation.

Influence of Spent Bleaching Earth and Misspend Cement on Shear Strength Behaviour of Unsaturated Clays

Expansive clay is a major source of undulations induced in any type of structures. Swelling of expansive soils causes serious problems and produces harm to many structures. Many research organizations are doing extensive work on waste materials concerning the viability and environmental suitability. Spent bleaching earth and misspend cement are waste derivatives from oil industry and cement warehouse. To avoid dumping problem and storage problems, it is the best method technique applied in expansive soils. Attempts are made to investigate the stabilization process identified in unconfined compressive strength and tri-axial compressive strength.Stability of any structure depends on strength properties of underground soil on which it is constructed. Structures basically transfer all the loads come on itself directly to the ground. If the underlying soil is not stable enough to support transferred loads then various types of failure occur such as settlement of the structure, cracks and so on. To solve this issue, soil improvement is necessary because it not only lowers the construction cost but also cuts the risk of any damage of structure later on. Numerous improvement methods can be adopted to make ordinary soil stable enough to support the structural loads. In this research work a number of tests may conduct using both ordinary soil and stabilised soil. This thesis explains the strength behavior of SBE treated black cotton soil reinforced with MC. The various percentage of SBE as 5%, 10%, 15%, 20% and 25% was used to find out the optimum value of RBI Grade. MC has been randomly included into the SBE treated soil at four different percentages of MC content, i.e. 2%, 4%, 6%, 8% and 10%.

Damage and failure characteristics of CFRP/aluminum single lap joints designed for lightweight applications

In this study, a full-factorial experimental design was employed for evaluating mechanical behavior of riveted, adhesively bonded and hybrid joints. The effects of significant design factors including overlap length, rivet diameter and adhesive thickness on progressive failure process of CFRP/Al6061-T6 single lap joints under quasi-static loads were investigated using high speed imaging technique. The complex strain distributions were evaluated using digital image correlation method. Results showed that load-displacement curves and failure process of hybrid joints presented two stages to prevent premature joint failure. Final failure mechanisms of hybrid joints were significantly affected by rivet diameter, while independent on overlap length and adhesive thickness. Various types of failure including severe adhesive and cohesive failure, fiber-tear failure and rivet fracture were found on damaged surfaces of hybrid joints using 3.0 mm diameter rivet, while joints using 5.0 mm diameter rivet were featured with flexural fracture of CFRP substrate.

OPTIMIZATION OF SIMPLY SUPPORTED CASTELLATED I-BEAMS LOADED BY A UNIFORMLY DISTRIBUTED LOAD

The paper discusses the problem of optimizing the geometric parameters of simply supported I-beams in order to maximize their load carrying capacity. Numerical simulation of various types of failure of castellated I- beams with ideal elastic-plastic steel is carried out. The stability of the wall, the strength of the welds and flanges, depending on the geometric parameters investigated. Using the coordinate descent method, the optimization prob­lem is solved for nine design schemes with respect to the section height and the weld length. It was revealed that in short beams the section height should be less and the weld length longer, in contrast to long beams.

Dependence of Microcontroller Failure Parameters via Ultrashort Radio Pulses under Operation Conditions

In this paper, we studied the functional failure of microcontroller (MC) ATmega8515 under ultrashort pulse series action at clocking frequencies of 1, 8, and 15 MHz. We analyzed the probabilities of occurrence in various types of failure and their connection with clocking frequency and magnitude of field strength. The correlation of MC failure with its operation phase is shown. The possibility to study, at least qualitatively, the behavior of complex electronic systems using well-known mathematical models was demonstrated.

ANALISIS FAKTOR-FAKTOR YANG MEMPENGARUHI KERUSAKAN BAN PADA UNIT DUMP TRUCK DI PT X

Tire is important component of a Dump Truck. For transporting material from the loading point and fleet to disposal Dump Truck performance is required. Trouble On the tire will interfere the unit performance. Month period data from January to March show the amount of failure to the unit HD785-7 dump truck tire which can indirectly interfere the performance of the unit. Therefore, analysis of two key performance indicator (KPI) that tread utility ratio (TUR) and lifetime must be done to find the factors that cause failure, as well as find out whether there is a relationship between lifetime and TUR against different types of failure that occurred by using logistic regression. From the analysis, it is known that the tire KPI has yet to reach a given target, the main factor of tire performance has yet to reach the target is human error, operator Dump Truck and Excavator by 44%, from the results of logistic regression analysis of the data for 3 months it is known that the relationship LifeTime and TUR against various types of failure is not significant because Chisq value is greater than the value of 0.05 pr. (5%).

Investigation of random inclusion of bamboo fiber on ordinary soil and its effect CBR value

Stability of any structure depends on strength properties of underground soil on which it is constructed. Structures basically transfer all the loads comes on itself directly to the ground. If the underlying soil is not stable enough to support transferred loads then various types of failure occur such as settlement of the structure, cracks and so on. To solve this issue, soil improvement is necessary because it not only lowers the construction cost but also cuts the risk of any damage of structure later on. Numerous improvement methods can be adopted to make ordinary soil stable enough to support the structural loads. In this research work a number of tests were conducted using both ordinary soil and fiber reinforced soil. Soil samples for unsoaked and soaked CBR tests were prepared at its maximum dry density analogous to its optimum moisture content in the CBR mould with and without fiber. The reinforcing agent used in this study are natural bamboo fibers having diameter of 3 and 6 mm and length of 10 and 20 mm respectively. The proportion of bamboo fiber by waterless weight of normal soil was used as 0.20, 0.40, 0.60, 0.80, 1.00, 1.20 and 1.40%. Bamboo fiber is natural fiber, acts as a strengthening material for ordinary soil. It binds the soil particles together and helps in reduction of rapid change in volumetric properties. Addition of fiber improves the ductility behavior and increases the CBR value of ordinary soil. It was observed from the test results that unsoaked and soaked CBR value of soil increases with the increase in length and diameter of bamboo fiber. It was also found that increasing the percentage of bamboo fiber increases the CBR value of reinforced soil, and this increment is significant at fiber dosage of 1.2%. This significant increase of CBR value will diminish the thickness of pavement.

Advancement in maintenance operation for managing various types of failure and vastly ageing facilities

Chubu Electric Power Company Inc., one of the utilities in Japan, has been maintaining a large number of distribution facilities which were constructed in the 1970s, when the country was in the period of high-economic growth. These aged facilities are being replaced with improved ones to prevent faults. To improve maintenance operation, condition- and time-based maintenance has been introduced. To carry out more effective and efficient maintenance on increasing highly aged facilities, it is indispensable to maximise their life cycles and to average the replacement operation by upgrading the maintenance procedures. To respond to these issues, the management of equipment data are being improved by introducing label with two-dimensional barcode, and strengthening the analytical capability of defect information by developing ‘distribution asset management and replacement assist system’

ЧИСЛЕННАЯ МОДЕЛЬ МАКРОВЯЗКОГО РАЗРУШЕНИЯ СОВРЕМЕННЫХ СТАЛЕЙ МАГИСТРАЛЬНЫХ ГАЗОПРОВОДОВ

The paper discusses computer modeling of an extensive crack propagating in a gas pipeline, which (the modeling) plays an important role in determining resistivity of pipe steels to various types of failure. A modified local Gurson-Tvergaard- Niedelman (GTNm) model is presented which makes it possible to describe straight and oblique cuts, as well as a combination thereof, in viscous failure of small-size objects (bars, plates, shells). Details of the implementation of the GTNm model in the parallel FE computer program DANKO (developed in Russian Federal Nuclear Center - All-Russian Research Institute of Experimental Physics) are given. Parameters of the GTNm model have been determined based on laboratory experiments with specimens of a pipe steel of the K65 strength class. Numerical examples are given, demonstrating “working efficiency” of the GTNm model. The results are designed for numerically studying deformation, failure of specimens during tests, dynamic crack propagation in a pipeline. Keywords: steels of gas mains, small-dimension objects, viscous failure, oblique cuts, computer modeling, finite element method, modified local Gurson − Tvergaard − Niedelman (GTNm) model.

Estimating burst probability of water pipelines with a competing hazard model

Because pipeline systems represent more than 80% of the total asset value of water-distribution systems, their management is an important issue for water utilities. A pipeline deteriorates over time after installation and, along with the deterioration, pipe bursts can occur as various types, and the choice of a maintenance and repair strategy will depend on the burst types. It is therefore important to forecast the occurrence probability of each burst type. This paper addresses a competing deterioration-hazard model that allows modelling of deterioration by multiple types of failure and focuses on the bursts which occur in the pipe body or connection. The Weibull hazard model is used to address the lifetime of each pipeline, measured from when it was buried, and the model takes into account the competing nature of various types of failure by using a competing hazard model. The competing deterioration-hazard model allows us to determine the probability of deterioration in the pipe body and connection. The model is estimated by Bayesian inference using a Markov chain Monte Carlo method. The applicability of the method to data for an existing pipeline system is examined.

Study on the Fusion of the Train 5T System

Vehicle operation safety monitoring system (5T system) is the important means to guarantee the safe operation of the vehicle under the new situation of mixed passenger and freight rail transportation, speed, vehicles overloaded. The system using a variety of advanced motion detection technology, information processing technology and network technology to achieve real-time vehicle dynamic monitoring of running status. However, various types of failure of vehicle components are interacting and interrelated, in practical applications, there is a strong demand for information sharing, centralized monitoring and comprehensive analysis. Based on the actual research of Datong-Qinhuangdao line, a set of building methods of 5T information fusion are proposed, laid the foundation for the promotion of 5T information fusion.

Inference and Optimal Design Based on Step—Partially Accelerated Life Tests for the Generalized Pareto Distribution under Progressive Type-I Censoring

Various types of failure, censored and accelerated life tests, are commonly employed for life testing in some manufacturing industries and products that are highly reliable. In this article, we consider the tampered failure rate model as one of such types that relate the distribution under use condition to the distribution under accelerated condition. It is assumed that the lifetimes of products under use condition have generalized Pareto distribution as a lifetime model. Some estimation methods such as graphical, moments, probability weighted moments, and maximum likelihood estimation methods for the parameters are discussed based on progressively type-I censored data. The determination of optimal stress change time is discussed under two different criteria of optimality. Finally, a Monte Carlo simulation study is carried out to examine the performance of the estimation methods and the optimality criteria.

Social Comparison and Information Transmission in the Work Context

In the workplace, people can experience various types of failure and frustrations resulting in spontaneous social comparisons with other colleagues who are more (upward comparison) or less (downward comparison) successful. Upward comparisons especially have been shown to increase envy toward the outperforming benchmark colleague, which could negatively affect social interaction with this colleague. In line with this, our results consistently show that upward comparisons are associated with higher levels of experienced envy, as well as with a lower transmission rate of high‐quality information. By contrast, type of social comparison had no impact on the amount of transmitted low‐quality, work‐relevant information. Theoretical and practical implications are discussed.

Chronic Peritoneal Dialysis Catheters: Challenges and Design Solutions

Although highly successful as transcutaneous access devices, today's peritoneal dialysis catheters still have imperfect hydraulic function, biocompatibility and resistance to infection. Success of Tenckhoff catheters is greatly improved by the proper positioning of deep and subcutaneous cuffs and intraperitoneal segment. Newer peritoneal catheter designs are intended to improve hydraulic function, avoid outflow failure, and diminish exit site infection. These catheter designs serve as excellent alternatives for patients with various types of failure of Tenckhoff catheters. Catheters have been designed for Continuous Flow Peritoneal Dialysis, and have generally been successful in providing high peritoneal dialysis flow rate, but not always successful in optimally distributing flow of peritoneal fluid. Improvements in catheter design may expand the use of peritoneal dialysis as a successful home dialysis therapy.