Risk Analysis of Tunnel Water and Mud Inrush Using Interpretive Structural Modeling and Fault Tree

Water and mud inrush is a common geological hazard in tunnel construction. Risk analysis of tunnel water and mud inrush has always been an important subject. In order to avoid the geological hazard, this paper presents a risk analysis model of tunnel water and mud inrush. The model combines the interpretive structural modeling method (ISM) and fault tree analysis (FTA). Relying on the Qinyu tunnel in the Weiwu expressway project, water and mud inrush risk factors are obtained by using ISM. Fundamental risk factors include formation lithology, attitude of stratum, strata combination, topography and geomorphology, geological structure and weather. ISM core risk factors are used as FTA basic events. Fuzzy importance of FTA basic events is obtained by using fuzzy interval calculation. The results show that geological structure is the primary risk factor causing Qinyu tunnel water and mud inrush. The model achieves qualitative and quantitative analysis of tunnel water and mud inrush. It accurately determines the main factors affecting the tunnel water and mud inrush, which is conducive to accident prevention.

Análise da confiabilidade humana em um laboratório de análises clínicas utilizando FMEA e FTA

A análise de confiabilidade humana surge como suporte para quantificar e qualificar as falhas relacionadas às pessoas na execução de processos. Este trabalho apresenta um estudo de caso com o objetivo analisar a confiabilidade humana nos processos de atendimento de clientes e coleta de material biológico em um laboratório de análises clínicas. A pesquisa constituiu-se das seguintes etapas: revisão da literatura sobre os conceitos de falhas humanas e métodos para análise dessas falhas; mapeamento dos processos a fim de caracterizar falhas, levantamento do quantitativo de falhas por tipo e processo; análise do risco das falhas por meio da aplicação do método FMEA (Failure Mode and Effect Analysis); análise das causas das falhas, com o suporte de FTA (Fault Tree Analysis); e conclusões acerca das análises realizadas durante a pesquisa. Os levantamentos e análises realizados permitiram categorizar as falhas entre erros e transgressões e priorizar ações para preveni-las. Constatou-se que a ocorrência dessas falhas pode ser reduzida, se a qualificação profissional dos funcionários for consolidada.

Performance evaluation of after-sales service partners in the power tools industry

After-sales service (ASS) is a product support activity provided to customers; after-sales service that focuses on quality can create a sustainable competitive advantage. This study aims to the ASS performance, analyze the causes of performance constraints that occur in ASS and recommendations for improving the performance of ASS conceptually. Service partner performance achievement can be assessed from four categories, i.e. very good, good, bad, and poor, based on the actual level of performance compared to performance targets. The sample of this research is 12 ASS partners in the electrical equipment industry in West Java and Jakarta. Factors causing failure were analyzed descriptively using the fault tree analysis (FTA) method, which involved experts in focus group discussions (FGD). Based on the evaluation, 25% of partners were rated good, 50% poor, and 25% very poor. Partner performance achievement is carried out on 22 performance indicators, of which 20 performance indicators have not achieved a good rating. These indicators relate to brand issues, warranty, training, parts control and stock management, pricing, and service systems, including service centers and service facilities. The proposed concept that becomes a recommendation for improving the performance of power tools ASS is improving the operating system and the selection of partners in the service center and service dealer categories with industrial customer segmentation.

МОДЕЛИРОВАНИЕ СИСТЕМЫ УПРАВЛЕНИЯ ПРОЦЕССАМИ ЭКСТРЕННОГО РЕАГИРОВАНИЯ ПРИ ЧС И ПОЖАРАХ

Статья посвящена решению проблемы многоэтапного моделирования системы управления процессами экстренного реагирования при ЧС и пожарах с постепенным повышением детализации создаваемых моделей на основе метода дедукции. В работе обоснована актуальность решения данной проблемы, обусловленная необходимостью формализации процессов управления для обеспечения компьютерной поддержки процессов управления. Разработаны концептуальные и функциональные модели с последовательным уточнением и детализацией процессов. Разработано дерево ошибок на основе методологии анализа дерева отказов (Fault tree analysis, FTA) и системного подхода с многими состояниями системы (Multi-State System, MSS). Идентифицировано место системы управления в системе классификации социально-экономических систем (СЭС). Построенные модели предназначены для формализации процессов управления в условиях ЧС и пожаров с целью обеспечения возможности осуществления из информационно-аналитической поддержки.

Evaluation of the Main Causes of Diesel Engine Injector Failure using Fault Tree Analysis

This paper is based on the application of the root cause analysis principle of diesel engine injector failure in diesels Haditha station. The maintenance of the diesel engine injector contains many problems that lead to the injector stopping; several reasons lead to such Problems. Fault tree analysis (FTA) is one of the most widely used methods in the industrial sector to perform reliability analysis of complex engineering systems. A fault tree is a logical representation of the relationship of primary/basic events that lead to a given undesirable event (i.e., top event). This research aims to present the (FTA) technology and how to use it in analyzing the causes of problems that lead to the injector stop working, and how to calculate the probability of occurrence of such problems. Implementation of FTA based on the probabilities of the causes under the top event and canalization lead to the calculated probability value (0.80). The plant management can define a specific plan to reduce these problems, because failure of an important engine part (injector) with such a large value leads to long downtime hours compared to operating hours.

Identifikasi Faktor-Faktor Penyebab Berkontribusi Terjadinya Kegagalan Konstruksi Jalan dengan Metode Fault Tree Analysis (FTA)

Kegagalan konstruksi merupakan suatu kondisi penyimpangan, kesalahan dan kerusakan dari hasil pekerjaan konstruksi yang dapat mengakibatkan keruntuhan bangunan atau konstruksi. Penelitian ini bertujuan untuk mengidentifikasi faktor-faktor yang berkontribusi terjadinya kegagalan struktur jalan Bukit Manggis Kabupaten Solok Selatan menurut persepsi para stakeholder proyek. Metode penelitian menggunakan metode deskriptif kualitatif melalui observasi di lokasi proyek dan wawancara mendalam kepada para stakeholder. Hasil data wawancara dianalisis menggunakan metode Fault Tree Analysis (FTA) dan Methode for Obtaining Cut Set (MOCUS). Berdasarkan hasil identifikasi, di peroleh 7 (tujuh) faktor-faktor yang berkontribusi terjadinya kegagalan pada struktur jalan yaitu; (1) Perencanaan, (2) Pelaksanaan, (3) Bencana alam, (4) Komunikasi, (5) Budaya organisasi, (6) Biaya serta (7) Kondisi iklim. Faktor-faktor kegagalan konstruksi paling dominan menurut persepsi stakeholder adalah bencana alam, kondisi iklim, budaya organisasi dan komunikasi. Maka dari itu, diharapkan masing-masing stakeholder memberikan perhatian khusus terhadap faktor penyebab yang telah diidentifikasi.

Operational failure assessment of Remotely Operated Vehicle (ROV) in harsh offshore environments

For an effective integrity assessment of marine robotic in offshore environments, the elements’ failure characteristics need to be understood. A structured probabilistic methodology is proposed for the operational failure assessment (OFA) characteristics of ROV. The first step is to assess the likely failure mode of the ROV system and its support systems. This captures the interaction and failure induced events during operation. The identified potential failure modes are further developed into logical connectivity based on the cause-effect relationship. The logical framework is modeled using the fault tree analysis technique to predict the ROV operational failure probability in an uncertain harsh environment. The fault tree analysis captured the logical relationship between the primary, intermediate, and top events probability. The importance measure criteria were adopted to identify the most probable events, links, and their importance on the failure propagation. The model was demonstrated with an ROV for deep arctic water subsea operations. The result identified the control system, communication linkages, human factor, among others, as most critical in the ROV operational failure. The methodology’s application provides core information on the Mean time between failure (MTBF) of the ROV system that could aid integrity management and provides a guide on early remedial action against total failure.