Use Of Fault Tree Analysis Research Articles

ANALISIS FAKTOR PENYEBAB KETERLAMBATAN PENYELESAIAN PADA PROYEK PEMBANGUNAN APARTEMEN URBAN SIGNATURE CIRACAS

The delay in completion of construction that has exceeded the work time target according to the initial agreement is very powerful on the construction project itself. Delays in the project occur due to problems that arise in terms of materials, labor, costs, equipment, environment, and others. In this research, an analysis was carried out on what factors were the cause of the delay in the completion of the superstructure and the rating of the value of the reliability function of each work. The Fault Tree Analysis (FTA) approach would be employed, which is a method that makes use of fault tree analysis in the form of a graphic model based on the outcomes of conducted interviews. In the graphic model, there were several event symbols and logic gate symbols to connect the event symbols. On the graphic model, the simplest cut set was acquired using Boolean algebra and the Method of Obtain Cut Set (MOCUS). Based on the results of the analysis, there were 33 basic events or jobs that experienced delays, including changes in rebar supply by the Owner, limited human resources, a lot of repair work, evaluation of the project schedule, SILO SIO PH licensing, late payments, delays in material delivery, and others. Typical structural work and ladder structures, the Boolean algebra law can be applied because it has a repeating code. Meanwhile, on the roof of the engine room, the law of algebra cannot be applied since the work does not have a repeating code. The reliability function is calculated in the analysis that follows. When all three variables are accurate, the system operates as intended.

Establishing failure patterns of a Belt Conveyor System configuration

Abstract: The conveyor belt is one of the most operational critical equipment’s in the mining industry, they are mostly used in the transportation of crushed materials from the crushing station to where there’ll be further processed. Due to the increasing complexity of belt conveyor systems, managing their integrity has become even more difficult, as they are now used across various industries, environments and carry materials of different weight variations, leaving them susceptible to failures (1). This paper provides an industry specific knowledge on belt conveyor systems, their respective components, and how they are configured using fault tree analysis to predict the different branches of event that can contribute to the failure of a belt conveyor system. The use of fault tree analysis sheds more light on how cascading failures can occur, where the failure of one component leads to the failure of the overall system. (2) Keywords: RCFA, FMEA Opex, FTA, Capex, Eca, Ttf, Ttr.

Computation of Importance Measures Using Bayesian Networks for the Reliability and Safety of Complex Systems

Modern engineering systems have proven to be quite complex due to the involvement of uncertainties and a number of dependencies among the system components. Shortcoming in the inclusion of such complex features results in the wrong assessment of reliability and safety of the system, ultimately to the incorrect engineering decisions. In this paper, the usefulness of Bayesian Networks (BNs) for achieving improved modeling and reliability and risk analysis is investigated. The calculation of a number of Importance Measures with use of Fault Tree Analysis as well as BNs is provided for a complicated railway operation problem. The BNs based safety risk model is investigated in terms of quantitative reliability and safety analysis as well as for multi dependencies and uncertainty modeling.

Sensitivity analysis of APR-1400’s Reactor Protection System by using RiskSpectrum PSA

Abstract The Advanced Pressurized Water Reactor (1400) offers greater power output than its predecessor, the Optimized Power Reactor (OPR-1000), hence required increased reliability and design limitations of its protection systems to be licensed for commercial operation. One of these systems is the Reactor Protection System (RPS), a set of subsystems and methods designed to fortify the integrity of the reactor. Compromise of RPS safety could stem from possible failures of subsystems, natural hazards, inadequate application of mitigation measures or human error. Probabilistic Safety Assessment is an effective and indispensable part of Nuclear Safety that is used within the assessment of RPS reliability. Alongside other techniques, it incorporates the use of fault-tree analysis to determine failure rates of top-events, but it requires input data in the form of initiating events. Unfortunately, accurate data on initiating events is hard to obtain and therefore, the use of conservative values was the norm in most studies. This signifies the importance of studying a handful of values around these conservative values. This paper focuses ontheAPR-1400 and aims to investigate the most promising elements to improve the reliability of its Reactor Protection System (RPS). The study was carried out using Risk Spectrum PSA, a tool used in more than 50% of nuclear reactors around the world. From 171 initiating events, trends and case studies for the 3 most sensitive elements in RPS were constructed and discussed. CCF-TCB, Operator and CC-DOP were found to be the most potent events in reducing RPS failure probability. This research should give an insight on how to tackle RPS-enhancements for future designs of Nuclear Power Plants.

A Framework for Assessing Technology Risks in Transaction-Based Extended Enterprises: U.S. Capital Market Case

Ensuring operational reliability of the technology-based systems processing transactions for industries such as the U.S. capital market is vital to the global economy. Within this context, monitoring operational IT risk levels (a component of enterprise risk management) across the various supply chains or “extended enterprises” (EEs) making up these highly automated sectors becomes particularly important. This paper proposes an approach for segmentation of complex industries such as the U.S. capital markets into EEs and assessing their IT operational risk level. The concept of EE technology risk index is introduced and modified with the use of fault tree analysis to help oversight groups monitoring technology risks for this type of industry. The proposed methodology is illustrated with one of the EEs within the U.S. capital market. Observations on the approach and potential future research is discussed.

Qualitative and quantitative approaches to analyse reliability of a mechatronic system: a case

The main research intent of this paper is to introduce the use of fault tree analysis (FTA) and failure mode and effects analysis (FMEA) in conjunction to ana- lyse the risk and reliability of a complex mechatronic system in both qualitative and quantitative manner. The major focus is on handling imprecise and vague informa- tion with the help of fuzzy synthesis of information. A complex mechatronic system, i.e. modular automated production system (MAPS), composed of mechanical, electronic, and embedded software subsystems is consid- ered to study the reliability aspects using hybrid FTA. From the results, it is found that the proposed approach models both subjective issues such as human errors along with hardware failures. The in-depth analysis and priori- tizing of failure modes using a risk ranking approach based on fuzzy inference system and grey relation approach not only integrate expert judgment, experience, and expertise in more flexible and realistic manner, but also address the limitations associated with traditional procedure of FMEA.

The Trends in Usage and Barriers of Innovation Management Techniques in New Product Development

This paper reports the results of a survey on the use of innovation management techniques (IMTs) with the potential to improve effectiveness of new product development (NPD), and customer satisfaction as well as about those barriers preventing their introduction in Slovene firms in the period from 2003 to 2011. The results show that small percentage of Slovene firms used IMTs. Failure mode and effects analysis (FMEA) was found as the most applied IMT in Slovene firms with the highest perceived utility potential to reduce development costs and improve customer satisfaction. Results also indicate a trend towards the increasing use of fault tree analysis (FTA), value analysis, target costing, and TRIZ especially during the period of 2008-2011 which coincides with the period of economic and financial crisis. IMT complexity, a needed coaching and training and the lack of input data for IMT usage were recognized as the main barriers to implementing IMTs in Slovene firms.

Analysis and Related Preventive Measures of Explosion Risk Factors of LPG Rail Transport

Railway transportation safety management must adhere to the approach of safety and prevention first. The transport of dangerous goods should be paid more attention as a particularly important part. This paper made use of fault tree analysis to research and analyze the risk factors of dangerous goods LPG which may explode in the rail transport. The analysis was made from two aspects of chemistry and physics, then the minimal cut sets and structure importance of the specific factors which may cause explosion accidents are solved, and the importance of each factor is analyzed and sorted on the calculated results. Based on the above method, measures of LPG rail transport explosion prevention were proposed.

Fault Tree Analysis of Schoharie Creek Bridge Collapse

The United States has witnessed several bridge collapses that have resulted in human fatalities. One such failure was the Schoharie Creek Bridge (1987), which motivated the improvement of bridge management policies and procedures. This paper offers a detailed review of the events that resulted in this bridge failure through the use of fault tree analysis. A fault tree is a graphical depiction of the various failure paths that lead to an undesirable outcome. The tree presented considers a host of catastrophic events ranging from vessel collision to fire. Fault trees also provide quantitative assessment and comparison of different failure mechanisms. The results of this analysis present scour as the source of the collapse of this bridge, which was in reality the root cause. Knowledge of the vulnerabilities particular to a bridge aids in the management of similar bridge types, allowing focus upon critical aspects. Recognition of historical bridge failures offers awareness to current bridge engineers and managers that aids in the decision making that promotes public safety and structure preservation. Lessons learned will help avoid similar catastrophic failures in the future.

The use of fault tree analysis to visualise the importance of human factors for safe diving with closed-circuit rebreathers (CCR)

Closed-circuit rebreathers (CCR) have been used for many years in military diving but have only recently been adopted by technical leisure divers, media and scientific divers. Rebreather divers appreciate the value of training, pre-dive checks and equipment maintenance but it is often difficult to visualise just how important these factors are and how they inter-relate for a rebreather. In this paper, the well-known technique of fault tree analysis (FTA) is used to identify risk in a rebreather. Due to space constraints, only the branch of the tree for unconsciousness as a result of hyperoxia is considered in detail but, in common with the whole tree, end events are shown to be humanfactor related. The importance of training to the emergency situation, the use of formal pre-dive checklists and the value of good design to prevent accident escalation are discussed further.

Semi-quantitative fault tree analysis for process plant safety using frequency and probability ranges

There is a growing concern in process plant safety to assess risk. Two important motives can be identified: on the one hand, the new Seveso directive, which contains a number of risk-related requirements for process plants, and on the other, the advent of the “Safety Integrity Level” SIL classes. These call for methods of analysis, which enable one to obtain reliable results at reasonable effort. The chief obstacle against the widespread use of fault tree analysis for analyzing the safety of process plants is the dearth of appropriate reliability data. This gives rise to time-consuming and error-prone searches in the analyses performed, which nevertheless suffer from the drawback that they do not exactly reflect the situation because the reliability data is not plant-specific. This being the case, in the present approach generic ranges for reliability data are used. These are considered to reflect the uncertainty of the reliability data caused amongst others by their transfer from the conditions of origin to other plants. These uncertainties are propagated in evaluating the fault tree and yield results at both the minimal cut set and structure function levels characterized by natural language expressions. Numerical results are supplied as additional hints for system improvement. The source for the reliability data assignments is a quality assured evaluation in two plants of the explosives industry. The method is implemented in the program system Semi-Quantitative Fault Tree Analysis (SQUAFTA), which was successfully applied to the analysis of a process plant.

Safety and reliability considerations for lithium batteries

Battery safety and reliability are closely related and, in some instances, safety may be considered a subset of reliability. However, safety is a concern from manufacture through disposal. Reliability can be approached through three different perspectives: lot reliability, individual cell reliability, and root cause analysis of failed cells. To ensure a quality product, a good reliability management program must be established as part of the manufacturing process. Reliability can be designed into cells through the use of fault tree analysis, while root cause analysis of failed cells is determined by a thorough post mortem analysis of individual failed cells. An existing fault tree can help focus the analysis. Battery safety can be classified as to the different types of hazards according to their effect on personnel and equipment, e.g., physical, chemical, equipment damage, and environmental. To maximize safe performance, each cell and battery should be designed specifically for its intended use. Battery packs must be designed to maintain the safety features designed into individual cells. However, the ultimate responsibility for battery safety lies with the consumer, who must insure proper storage conditions, train personnel in proper handling techniques, and dispose of them in accordance with government regulations.

A Reappraisal of Probabilistic Risk Analysis

ABSTRACTThis article is a critique on the use of fault-tree analysis, probability calculus, and the concept of acceptable risk for addressing issues of public safety. Probabilistic risk analysis has been introduced into public debate to demonstrate the safety of technological hazards; however, its applicability is questioned because the analysis' methodology contains several serious flaws. These flaws include incompleteness, inaccuracy, and inappropriateness. Examples from recent accidents are used to illustrate these flaws.

An assessment of coal mine escapeway reliability using fault tree analysis

The issue of miner safety in case of an underground mine fire has been extensively examined by both government and industry. These efforts have intensified in recent years following a number of fatal fires at underground coal mines. As a result, there is an increasing interest in the reliability of coal mine escapeways during a mine fire. This paper discusses the use of fault tree analysis for evaluating escapeway reliability. A fault tree is developed using standard logic formulations. It is later evaluated using commercially available software. The computer model uses Boolean reduction to obtain the minimal cut sets and minimal path sets of the tree. A brief analysis is also conducted to determine the occurrence probability of the TOP event. This study shows that fault tree analysis is a viable means of analyzing escapeway reliability. The cut and path sets reveal those event sequences leading to fatalities. Such information is useful in safety training and accident prevention. The probability of the TOP event shows the frequency of occurrence for fatalities in an underground mine fire. The usefulness of this value, however, is limited by the accuracy of the data for the initiating events. For mining events, the data are difficult to estimate precisely.

Mine power system reliability

The research done over the last decade or so to apply the principles of reliability theory to mine electrical power systems is summarized. The multifaceted effort to estimate the failure rates of equipment applicable to the mine environment is examined, and the use of fault-tree analysis to predict the probability of hazardous voltages on the frames of various pieces of mining equipment is dealt with. >

Fault tree safety analysis of a large Li/SOCl 2 spacecraft battery

The use of Fault Tree Analysis allows designers to identify the relative importance of events and their probabilities in leading to a catastrophic failure of a spacecraft battery. Such an analysis is demonstrated for the case of a 576 cell Li/SOCl 2 battery, showing how the probability of catastrophic failure can be reduced to one in one million.

A Matrix‐Based Approach to Uncertainty and Sensitivity Analysis for Fault Trees1

System unavailabilities for large complex systems such as nuclear power plants are often evaluated through use of fault tree analysis. The system unavailability is obtained from a Boolean representation of a system fault tree. Even after truncation of higher order terms these expressions can be quite large, involving thousands of terms. A general matrix notation is proposed for the representation of Boolean expressions which facilitates uncertainty and sensitivity analysis calculations.

Vital Area Penetration Significance

The use of Fault Tree Analysis has recently been recognized by security design engineers as a valuable tool in determining the protection levels which should be applied to various areas in the protected facility. This paper describes how these techniques may be extended to provide the engineer with an assessment of the significance of each of the previously defined vital areas. The technique utilizes point penetration probabilities for each of the areas to provide an index which measures the impact of penetrating the area in question upon the overall security of the facility. The effect of varying the penetration resistance of each area is then investigated. An example is provided to show how the technique is utilized by the design engineer to determine design requirements for each of the areas. While this technique has been specifically applied in this paper to the security field, it is also applicable to assessing the impact of variations in individual component reliabilities in a standard Fault Tree Analysis.

A qualitive fault tree analysis for the tensile failure of fibrous laminated composites

The use of fault tree analysis for the identification of failure modes and mechanisms for laminated composite materials is discussed. The fault tree technique is first defined and a synopsis of the technique as well as a synopsis of the failure of composites is given. The two, fault tree analysis and elements of composite failure, are then combined to identify a fault tree for composite failure. The elements of fault tree are discussed qualitatively in relation to the likely failure modes for composites such as delamination, fibre breakage, matrix cracking, etc. Further, the necessity for quantitizing the fault tree described is outlined.

Safety Investment Allocation by Dynamic Programming1

Abstract A two-phase model is proposed for determining and evaluating alternative safety investments. The first phase involves the analysis of safety problems by the use of Fault Tree Analysis. The resulting Fault Trees are then used to establish the probabilistic structure through which the returns of safety investments can be determined. This is integrated into a dynamic programming algorithm so that the variety of discrete alternatives can be evaluated under the constraints of a total safety budget.