162 research outputs found

    An Optimal Number-Dependent Preventive Maintenance Strategy for Offshore Wind Turbine Blades Considering Logistics

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    In offshore wind turbines, the blades are among the most critical and expensive components that suffer from different types of damage due to the harsh maritime environment and high load. The blade damages can be categorized into two types: the minor damage, which only causes a loss in wind capture without resulting in any turbine stoppage, and the major (catastrophic) damage, which stops the wind turbine and can only be corrected by replacement. In this paper, we propose an optimal number-dependent preventive maintenance (NDPM) strategy, in which a maintenance team is transported with an ordinary or expedited lead time to the offshore platform at the occurrence of the Nth minor damage or the first major damage, whichever comes first. The long-run expected cost of the maintenance strategy is derived, and the necessary conditions for an optimal solution are obtained. Finally, the proposed model is tested on real data collected from an offshore wind farm database. Also, a sensitivity analysis is conducted in order to evaluate the effect of changes in the model parameters on the optimal solution

    PENENTUAN PENJADWALAN PREVENTIVE MAINTENANCE PADA KOMPONEN MESIN CALLENDER DI PT. KARET NGAGEL SURABAYA WIRA JATIM

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    PT. Karet Ngagel Surabaya Wira Jatim adalah perusahaan yang bergerak dalam bidang pembuatan karet. Dengan berkembangnya bisnis properti dan meningkatnya pemakaian karet siap pakai saat ini, melihat kondisi yang telah dijelaskan. Oleh karena itu perlu diberlakukan proses pemeliharaan yang terencana pada setiap mesin produksi. Selama ini perusahaan hanya menggunakan sistem break down maintenaince yaitu ketika mesin mati atau alat mengalami kerusakan baru dilakukan perbaikan. Untuk memberikan solusi terbaik, kami sebagai penulis mengambil langkah untuk melakukan penelitian dengan menggunakan metode preventive maintenance yang bertujuan untuk meminimalisir kerusakan fatal pada komponen mesin. Kerusakan komponen Carbon Brush pada mesin Callender dalam rentan waktu Januari 2017 sampai dengan Desember 2017 tercatat kerusakan sebanyak 18 kali, pada mesin Callender terdapat 18 komponen Carbon Brush. Dari hasil penelitian yang telah dilakukan preventive maintenance dengan menggunakan metode Age Replacement. Penentuan penjadwalan interval waktu penggantian Spring Carbon Brush sebagai bentuk mengoptimalkan biaya down time dengan menggunakan metode Age Replacement di PT. Karet Ngagel Surabaya Wira Jatim diperoleh interval waktu penggantian yang paling optimal adalah 18 hari dan terjadi 16 kali perbaikan komponen dalam 1 tahun kedepan Penghematan biaya down time sebesar Rp.1.710.000,- atau 37.25% dibandingkan dengan sebelum menggunakan penjadwalan dengan metode Age Replacement. Kata kunci: Preventive Maintenance, down time, Spring Carbon Brush, Age Replacement

    A review on maintenance optimization

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    To this day, continuous developments of technical systems and increasing reliance on equipment have resulted in a growing importance of effective maintenance activities. During the last couple of decades, a substantial amount of research has been carried out on this topic. In this study we review more than two hundred papers on maintenance modeling and optimization that have appeared in the period 2001 to 2018. We begin by describing terms commonly used in the modeling process. Then, in our classification, we first distinguish single-unit and multi-unit systems. Further sub-classification follows, based on the state space of the deterioration process modeled. Other features that we discuss in this review are discrete and continuous condition monitoring, inspection, replacement, repair, and the various types of dependencies that may exist between units within systems. We end with the main developments during the review period and with potential future research directions

    Maintenance optimization and spare parts management in data-integrated environments

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    Maintenance optimization and spare parts management in data-integrated environments

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    Joint optimisation of inspection maintenance and spare parts provisioning: a comparative study of inventory policies using simulation and survey data

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    The demand for industrial plant spare parts is driven, at least in part, by maintenance requirements. It is therefore important to jointly optimise planned maintenance and the associated spare parts inventory using the most appropriate maintenance and replenishment policies. In this simulation-based study, we address this challenge in the context of the random failure of parts in service and the replacement of defective parts at inspections of period T. Inspections are modelled using the delay-time concept. A number of simultaneous periodic review and continuous review replenishment policies are compared. A paper making plant provides a real context for the presentation of our ideas. We survey practitioners working with such plant to collect real data that inform the values of parameters in the models. Our simulation results indicate that a periodic review policy with ordering that is twice as frequent as inspection is cost optimal in the context of the plant that we study. For the purpose of comparison, we also present and discuss the characteristics of the various policies considered
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