Identification of key subsystems for urban rail vehicles based on fuzzy comprehensive evaluation

Abstract Identification of key subsystems for urban rail vehicles is important for the selection of maintenance strategy. The fuzzy comprehensive evaluation technique is applied to determine the key subsystems of urban rail vehicles. Firstly, the vehicle is divided into nine subsystems according to the module partition method. Then, the degrees of occurrence, severity, detection and maintenance cost are chosen as the evaluation factors that are quantified based on fuzzy theory and collected historical data. Finally, the calculation model of critical degree is established based on the fuzzy comprehensive evaluation method. The proposed approaches are applied to Guangzhou Metro Corporation, and five key subsystems are selected. The experiment results, which are consistent with those of most knowledgeable engineers and experts, indicate the validity of the proposed method

Data-driven system reliability and failure behavior modelling using FMECA

System reliability modelling needs a large amount of data to estimate the parameters. In addition, reliability estimation is associated with uncertainty. This paper aims to propose a new method to evaluate the failure behavior and reliability of a large system using failure modes, effects and criticality analysis (FMECA). Therefore, qualitative data based on the judgment of experts is used when data is not sufficient. The subjective data of failure modes and causes has been aggregated through the system to develop an overall failure index (OFI). This index not only represents the system reliability behavior but also prioritizes corrective actions based on improvements in system failure. In addition, two optimization models are presented to select optimal actions subject to budget constraint. The associated costs of each corrective action are considered in risk evaluation. Finally, a case study of a manufacturing line is introduced to verify the applicability of the proposed method in industrial environments. The proposed method is compared with conventional FMECA approach. It is shown that the proposed method has a better performance in risk assessment. A sensitivity analysis is provided on the budget amount and the results are discussed.Hadi A. Khorshidi, Indra Gunawan, and M. Yousef Ibrahi

Using EWGM Method to Optimise the FMEA as a Risk Assessment Methodology

YesFailure Modes and Effect Analysis (FMEA) is a proactive, highly structured, and systematic approach for failure analysis. It has been also applied as a risk assessment tool, by ranking potential risks based on the estimation of Risk Priority Numbers (RPNs). This paper develops an improved FMEA methodology for strategic risk analysis. The proposed approach combines the Analytic Hierarchy Process (AHP) technique with the Exponential and Weighted Geometric Mean method (EWGM) to support risk analysis. AHP is applied to estimate the weights of three risk factors: Severity (S), Occurrence (O) and Detection (D), which integrate the RPN for each risk. The EWGM method is applied for ranking RPNs. Combining AHP with EWGM allows avoiding repetition of FMEA results. The results of the developed methodology reveal that duplication of RPNs has been decreased, and facilitating an effective risk ranking by offering a unique value for each risk. The proposed methodology focuses not only on high severity values for risk ranking but also it considers other risk factors (O and D), resulting in an enhanced risk assessment process. Furthermore, the weights of the three risk factors are considered. In this way, the developed methodology offers unique value for each risk in a simple way which makes the risk assessment results more accurate. This methodology provides a practical and systematic approach to support decision-makers in assessing and ranking risks that could affect long-term strategy implementation. The methodology was validated through the case study of a power plant in the Middle East, assessing 84 risks within 9 risk categories. The case study revealed that top management should pay more attention to key risks associated with electricity price, gas emissions, lost-time injuries, bad odor, and production.This research has been supported by Hashemite University, Jordan

Proactive machine maintenance system

Tato práce řeší problematiku proaktivního systému údržby se zaměřením na obráběcí stroje. Jsou zde popsány nejčastější poruchy a nejrozšířenější diagnostické metody obráběcích zařízení. V práci je popsán postup analýzy způsobů, důsledků a kritičnosti poruch FMEA/FMECA, její možný další budoucí vývoj, a to s názornou ukázkou aplikace této analýzy na automatický soustruh CNC. Dále je v praktické části vybrána, popsána a vyhodnocena vibrační diagnostika obráběcího zařízení. Následně je doporučen postup v oblasti řešení zavádění systému údržby ve firmě SMC Industrial Automation CZ s.r.o. Vyškov.This bachelor thesis concerns issues of proactive maintenance, which is focused on machine tools. The most common failures and the most widespread methods of diagnostics of machine tools are described in the thesis. There are also described the procedure of Failure mode, effects and criticality analysis FMEA/FMECA, its possible development in the future with demonstrative presentation of application this analysis on CNC automatic lathe. Subsequently, in the practical part there has been chosen, described and appraised diagnostic of vibrations. Prior to the end the process in field of solving of establishment systems of maintenance has been recommended for SMC Industrial Automation CZ LLC Vyškov.

Risk analysis of crane operation

Téma diplomové práce je zaměřeno na oblast zajištění bezpečnosti zdvihací techniky. Konkrétně na prevenci chyb obsluhy mostového jeřábu a na zvýšení spolehlivosti lidského činitele. V práci jsou shrnuty nejdůležitější legislativní předpisy pro provozovatele jeřábu včetně požadavků na obsluhu. Dále jsou zde uvedeny analýzy nehod mostových jeřábů, ke kterým došlo společně s údaji o počtu pracovních úrazů. Součástí práce jsou dále řešené analýzy HTA, human HAZOP, BOMECH a FMEA. Na základě těchto vypracovaných analýz jsou stanoveny závěry a navržena preventivní opatření.The topic of this master's thesis is focused on the area of safety in lifting technology. Specifically, to prevent mistakes during bridge crane operations and to increase reliability of the human factor. The thesis summarizes the most important legislative regulations for crane operators, including the requirements for operation. Furthermore, there are analysis of bridge crane accidents including data about number of occupational accidents. Other part of the thesis deals with analysis HTA, human HAZOP, BOMECH and FMEA. Conclusions are set based on these analyzes and preventive measures are suggested.

Integration of Failure Modes and Effects Analysis (FMEA) in the Engineering Design Process

ABSTRACT Integration of Failure Modes and Effects Analysis (FMEA) in the Engineering Design Process Hua-wei Wen Failure modes and effects analysis (FMEA) is one of the most practical design tools implemented in the product design to analyze the potential failures and to improve the design. The practice of FMEA is diversified and different approaches are proposed by different organizations and researchers from one application to another. Yet, the question is how to systematically utilize the features of FMEA along with the design process. This thesis aims to integrate different types of FMEA in the design process, which is considered as the mapping between customer requirements, product functions, and design components. These three design elements are the foundation of the integration model proposed in this thesis. The objective of this thesis is to develop an integration approach of FMEA in the design process. Particularly, an integration framework is developed to integrate FMEA and design process. Then, a step-by-step FMEA-facilitated design process is proposed to apply FMEA along with the design process. In the end, a detailed case study of a smartphone model is conducted to demonstrate and verify the proposed methodology. The expectedly benefits of the proposed methodology are the consistency of failure analysis information, and the utilization of the failure analysis information from one stage to the later stages of the design process