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Fuzzy-FMEA risk evaluation approach for LHD machine - a case study

Balaraju Jakkula, Raj Mandela Govinda, Murthy Chivukula Suryanarayana

Journal of Sustainable Mining

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2019

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Vol. 18, iss. 4

257--268

EN

Improvement of productivity has become an important goal for mining industries in order to meet the expected targets of production and increased price competitiveness. Productivity can be improved in different ways. The effective utilization of men and machinery is one such way. Equipment is prone to numerous unexpected potential failures during its operation. Failure Mode and Effect Analysis (FMEA) is one of the suitable techniques of reliability modeling used to investigate the failure behavior of a complex system. In conventional FMEA, the risk level of failures, a ranking of failures and prioritization of necessary actions is made on the basis of estimated Risk Priority Number (RPN). While this approach is easy and uncomplicated, there are a few flaws in acquiring the best approximation of the failure. The estimation of RPN is made by multiplying the Severity (S), Occurrence (O) and Detection (D) alone and irrespective of the degree of importance of each input. Hence, a new risk management approach known as the Fuzzy rule base interface system was proposed in this research in order to mitigate the failures. Fuzzy FMEA is designed in order to acquire the highest Fuzzy RPN value which will be used as the focus of enhancements to reduce the probability of occurrence of some kind of failure for a second time. This study focused on the Root Cause Analysis (RCA) of underground mining machinery such as Load-Haul-Dumper (LHD). 16 potential risks of various sub-system breakdowns were identified in Fuzzy FMEA. The highest value of RPN 168 (for potential failure mode-F9) was obtained for the electrical subsystem (SSE), as was the highest FRPN 117 (F9). There is a difference between the RPN and FRPN values. The FRPN value is obtained from Fuzzy field generation with consideration of the degree of importance of the given input data. In addition, the recommendations were made based on the analysis to reduce the uneven occurrence of failures.

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Proposal of new maintenance scheme of air brake system on semi-trailer combination

Ruman F., Grenčík J.

Diagnostyka

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2015

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Vol. 16, No. 2

11--19

EN

The paper deals with the proposal of new maintenance scheme of air brake system on a semi-trailer combination. The structure of semi-trailer and the current maintenance scheme of trailers are described with focus on the basic air brake system design. Analysis of wear and damage of air brake system components used on the semi-trailer combination based on real experience from practice and creation of the FMECA analysis of the system using software support are presented. Based on the analysis performed, a new scheme of maintenance was designed which was aimed at reduction of the risk related to failure consequences. Main objective was to reduce the impact of any failure in any component on the air brake system. Proposed intervals of preventive maintenance execution are based on the calculation of the total costs associated with the consequences of failures that may arise from them and compared with costs associated with service inspections carried out on the analysed semi-trailer fleet.

PL

W niniejszym artykule zaprezentowano nowy system eksploatacji pneumatycznego układu hamulcowego naczepy. Opisano w nim także obecną strukturę systemu technicznego naczepy z uwzględnieniem podstawowego układu hamulcowego. Przedstawiono opartą o rzeczywiste wyniki badań komputerową analizę zużycia i uszkodzeń elementów układu hamulcowego z wykorzystaniem metody FMEA. Na jej podstawie zaprojektowano nowy system eksploatacji analizowanego układu hamulcowego, charakteryzujący się zmniejszonym ryzykiem wystąpienia awarii. Głównym celem projektu było zredukowanie ryzyka wystąpienia uszkodzeń poszczególnych elementów układu hamulcowego. Zaproponowane terminy przeglądów profilaktycznych są wynikiem porównania ogółu kosztów wynikających ze skutków możliwych awarii a kosztami związanymi z kontrolą serwisową dla analizowanej grupy naczep.

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Proposal of new maintenance system of air brake system on semi-trailer combination aimed at increase of operational safety

Grenčík J., Ruman F.

Autobusy : technika, eksploatacja, systemy transportowe

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2013

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R. 14, nr 3

1385-1392

EN

The paper deals with the proposal of new maintenance system of air brake system on a semitrailer combination. The structure of semi-trailer and the current maintenance system of trailers are described with focus on the basic air brake system design. Analysis of wear and damage of air brake system components used on the semi-trailer combination based on real experience from practice and creation of the FMECA analysis of the system using software support are presented. Based on the analysis performed, a new system of maintenance was designed which was aimed at reduction of the risk related to failure consequences. The proposed system uses RPN (risk priority number) values resulting from the proposed preventive maintenance system and is compared with the currentmaintenance system. Main objective was to reduce the impact of any failure in any component on the air brake system. On the basis of the analysis subsequently new methods of failures detection of air brake system components, preventive measures, and suggested new intervals of preventive maintenance for the air brake system are also proposed. Proposed intervals of preventive maintenance execution are based on the calculation of the total costs associated with the consequences of failuresthat may arise from them and compared with costs associated with service inspections carried out on the analysed semi-trailer fleet. The proposed maintenance system has decreased RPN values in comparison with the current system and in practical operation is expected to increase safety of semitrailer combinations, thus minimize probability of a failure in any component of the air brake system.

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Characteristic of quality improvement the proposal of measurement the process improvement managed by FMEA

Rewilak J.

Advances in Manufacturing Science and Technology

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2011

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Vol. 35, nr 4

51-62

EN

The paper presents a concept of index for measuring the quality of improvement managed by FMEA (Failure Mode and Effects Analysis). Quality assessed only by RPNs (Risk Priority Numbers) does not properly describe achieved improvement in terms of risk reduction, which can be obtained by preventive and / or detective controls. With increasing criticism of RPN based FMEA philosophy, a need for more relevant measures of quality improvement arises. The paper introduces a set of indices which can help FMEA teams / leaders, project managers, quality managers, SQA (Supplier Quality Assurance) engineers, etc. to identify at each stage of product/process development what improvement strategy has been applied - focusing on detection of problems or rather preventing their causes.

PL

W pracy przedstawiono nową koncepcję wskaźników opisujących skuteczność doskonalenia jakości uzyskiwanej przez zastosowanie metody FMEA (Failure Mode and Effects Analysis - Analiza Rodzajów i Skutków Wad). Podstawą przyjętej koncepcji jest postulat kwestionujący jednoznaczność oceny efektów doskonalących uzyskiwanych przy użyciu wskaźnika RPN (Risk Priority Number) podstawowego dla metody FMEA. Nie uwzględnia bowiem strategii uzyskiwania zmniejszenia ryzyka, która może być nastawiona na działania prewencyjne lub kontrolne (w konstrukcji wyrobu lub projekcie procesu). Nasilająca się krytyka wskaźnika RPN jako miary ryzyka stwarza konieczność stosowania innej miary doskonalenia jakości. Przedstawiono zestaw wskaźników istotnie wspomagających analizę ryzyka wyrobu / procesu (liderzy zespołów, kierownicy projektów, kierownicy jakości, osoby odpowiedzialne za jakość dostawców) w ocenie realizowanej strategii zmniejszenia ryzyka. Zaproponowane wskaźniki pozwalają na ilościową ocenę udziału i skuteczności działań kontrolnych - wykrywających wady lub przyczyny oraz działań zapobiegawczych, eliminujących przyczyny powstawania wad, z uwzględnieniem ich następstw dla wyrobu, procesu i klienta.