Génération d'indicateurs de maintenance par une approche semi-paramétrique et par une approche markovienne

National audienceLes stratégies de maintenance et leurs évaluations demeurent une préoccupation particulièrement forte au sein des entreprises aujourd'hui. Les enjeux socio-économiques dépendant de la compétitivité de chacune d'entre elles sont de plus en plus étroitement liés à l'activité et à la qualité des interventions de maintenance. Une suite d'évènements particuliers peut, éventuellement, informer l'expert d'une panne prochaine. Notre étude tente d'appréhender "cette signature" à l'aide d'un modèle de Markov caché. Nous proposons à l'expert deux stratégies sur l'estimation du niveau de dégradation du système maintenu. La première stratégie consiste à utiliser des lois de dégradation non paramétriques. La deuxième stratégie consiste à utiliser une approche markovienne

Procena rizika zastoja dizalica

According to available literature, safety at work and productivity of cranes are a necessary and insufficiently researched topic. Both research directions are closely related because they depend on the number and type of stoppages that occur during operation of these construction machines. The focus of research should be on identifying the stoppages that can have fatal consequences for employees on-site, or unintended consequences in terms of production loss, means of work, or environment. In the present research, an attempt is made to create a methodology for identification, analysis, assessment, classification, and calculation of stoppage risk in cranes (classified by categories and causes). Criteria used for analysis, assessment, and calculation of stoppage risk: degree of stoppage danger, frequency of stoppage classified according to stoppage categories/causes, and downtime according to the adopted classification. Experimental research on a sample of 1,091 stoppages recorded on several cranes over a longer time interval has confirmed the hypothesis of generating a 3-criterion matrix for stoppage risk assessment sensitive enough to prioritise key crane stoppage in terms of risk. Results of experimental research indicate mechanical downtime of 16.22 %, a frequency 45.35 % in downtime, and RPN number 80, at hazard level 10. Selectively, according to the cause of stoppage, the results indicate that the hoisting brake (6.48 % downtime at hazard level 10; 2.14 % stoppage frequency) and hoist gear/tooth breakage (5.29 % downtime at hazard level 10; 3.58 % stoppage frequency) are key mechanical causes of stoppages and crane risk generators. By mitigating the given risks, it is possible to improve safety and increase productivity.Prema dostupnoj literaturi, bezbednost u radu i produktivnost dizalica je potrebna i nedovoljno proučena oblast. Oba pravca istraživanja su u bliskoj vezi jer zavise od broja i tipa zastoja koji se događaju u toku rada ovih mašinskih konstrukcija. Predmet istraživanja treba da bude u identifikaciji ovih zastoja, koji mogu imati fatalni ishod po zaposlene na terenu, ili nepredviđene posledice u smislu proizvodnih gubitaka, radnih sredstava, ili na okolinu. U radu je predstavljena izrada metodologije za identifikaciju, analizu, procenu, klasifikaciju i proračun rizika zastoja (sa klasifikacijom prema kategoriji i uzroku) kod dizalica. Kriterijumi upotrebljeni za analizu, procenu i proračun rizika zastoja su: stepen opasnosti zastoja, frekvencija zastoja sa klasifikacijom prema kategorijama/uzrocima zastoja, kao i vreme prekida, prema usvojenoj klasifikaciji. Eksperimentalno istraživanje na uzorku od 1091 zastoja, zabeleženih kod nekoliko dizalica tokom dužeg perioda potvrđuje hipotezu o generisanju 3-kriterijumske matrice za procenu rizika zastoja, dovoljno osetljivom, kako bi se dao prioritet ključnim zastojima kod dizalice s obzirom na rizik. Rezultati eksperimentalnog istraživanja pokazuju period mehaničkih prekida rada sa procentom 16.22 % i frekvencijom 45.35 % u vremenu prekida, sa brojem RPN od 80, pri nivou rizika 10. Selektivno, a prema uzroku zastoja, rezultati pokazuju da su: kočnice (6.48 % vreme prekida sa nivoom rizika 10; 2.14 % frekvencije zastoja), zatim otkazi prenosnika/zubaca (5.29 % vreme prekida, sa nivoom rizika 10; 3.58 % frekvencije zastoja), ključni mehanički uzročnici zastoja i generatori rizika dizalica. Ublažavanjem datih rizika, moguće je poboljšati bezbednost i povećati produktivnost

Crane stoppages risk assessment

According to available literature, safety at work and productivity of cranes are a necessary and insufficiently researched topic. Both research directions are closely related because they depend on the number and type of stoppages that occur during operation of these construction machines. The focus of research should be on identifying the stoppages that can have fatal consequences for employees on-site, or unintended consequences in terms of production loss, means of work, or environment. In the present research, an attempt is made to create a methodology for identification, analysis, assessment, classification, and calculation of stoppage risk in cranes (classified by categories and causes). Criteria used for analysis, assessment, and calculation of stoppage risk: degree of stoppage danger, frequency of stoppage classified according to stoppage categories/causes, and downtime according to the adopted classification. Experimental research on a sample of 1,091 stoppages recorded on several cranes over a longer time interval has confirmed the hypothesis of generating a 3-criterion matrix for stoppage risk assessment sensitive enough to prioritize key crane stoppage in terms of risk. Results of experimental research indicate mechanical downtime of 16.22 %, a frequency 45.35 % in downtime, and RPN number 80, at hazard level 10. Selectively, according to the cause of stoppage, the results indicate that the hoisting brake (6.48 % downtime at hazard level 10; 2.14 % stoppage frequency) and hoist gear/tooth breakage (5.29 % downtime at hazard level 10; 3.58 % stoppage frequency) are key mechanical causes of stoppages and crane risk generators. By mitigating the given risks, it is possible to improve safety and increase productivity

E-maintenance platform design for public infrastructure maintenance based on IFC ontology and Semantic Web services

As an important kind of infrastructure, a tunnel's life is estimated to be 100 years or more. During its service life, an effective maintenance strategy plays an essential role in keeping its availability and safety. Maintenance work involves a set of participants, activities, and resources, and in this case, tunnel-related data are distributed to heterogeneous information management systems in varying formats, bringing difficulties to implement effective maintenance. This paper proposes an E-maintenance Framework for Public Infrastructure (EFPI), combining Building Information Modeling (BIM), Industry Foundation Classes (IFC), and Semantic Web technologies to help integrate heterogeneous data and expert knowledge, enable information sharing through the whole life cycle, and support maintenance managers to make effective maintenance decisions. A cost estimation case is provided in this paper to illustrate the implementation mechanism and validate the proposed approach

About intelligent maintenance and diagnosis techniques for mechatronic systems : case study using fractional order calculus

Orientadores: João Maurício Rosário, José António Tenreiro MachadoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia MecânicaResumo: A competitividade no mercado global exige cada vez mais a fabricação de produtos de alta qualidade em curto tempo de fabricação, evitando tempos de parada para manutenção e reparo de máquinas e equipamentos, exigindo assim um eficiente controle de qualidade do processo e dos produtos para evitar a ocorrência de falhas de fabricação e utilização. A integração de novas tecnologias em produtos industriais (ex. tecnologias mecatrônicas) exige a utilização de técnicas avançadas para o diagnóstico de falhas, a partir de análise dos sinais obtidos a partir do sensoriamento dos equipamentos, minimizando assim os custos de utilização de mão de obra especializada para controle de qualidade do produto. Neste trabalho é apresentado inicialmente, um estudo sobre o estado da arte em técnicas de manutenção industrial, com ênfase nas estratégias utilizadas para manutenção corretiva, periódica e baseada no comportamento com ênfase no estudo das técnicas de processamento do sinal e identificação de sistemas, frequentemente utilizadas no diagnóstico de sistemas mecatrônicos, que exigem uma grande quantidade de informações, e forte dependência da análise criteriosa de um técnico especializado. Assim, neste trabalho são utilizados sistemas de ordem fracionária, que permite a aproximação do comportamento real do sistema por meio de modelos com menos coeficientes que o sistema real, simplificando a análise do sistema em estudo. Um estudo experimental de caso para validação do trabalho é realizado a partir de uma bancada experimental de um sistema de transmissão por engrenagens que permitiu introduzir falhas particulares no sistema e sua identificaçãoAbstract: The global market competitiveness requires to make high quality products in a short time of manufacturing, avoiding stop-times due to maintenance and repairing of machines and devices, therefore, demanding an efficient quality control of the manufacturing process, in order to shun failures in fabrication and utilization. The integration of new technologies into industrial products (e.g. mechatronics technologies) requires the use of advanced techniques to a precise failure diagnosis. They are typically based on signal analyses, which are obtained from the machines' instrumentation, and consequently, reduce the manpower costs associated to quality control of particular products. In this work it is introduced a literature review of industrial maintenance techniques, focusing in the strategies used into corrective, periodic and condition based maintenance, specially using signal processing and system identification. Those paradigms are frequently applied into the mechatronics systems diagnosis, but requires a huge amount of information and it is strongly dependent on the specialist criterion. In this sense, we introduced a fractional order system approach, which results in a better approximation of the actual system through an few parameters architecture, hence simplifying the analysis of the actual system. A real experimental setup was used to validate the strategies studied in this work. It consist in a gear transmission that lets to introduce particular failures for a posterior identificationDoutoradoMecanica dos Sólidos e Projeto MecanicoDoutor em Engenharia Mecânic