Joint optimization of replacement and spare ordering for critical rotary component based on condition signal to date Wspólna optymalizacJa Wymiany i zamaWiania części zamiennych dla krytycznego komponentu obrotoWego na podstaWie dotychczasoWego sygnału stanu

Unexpected system failures pose significant problems in power industry and most manufacturing companies. In some cases, a critical component failure can incur catastrophic events and huge economic loss. To maintain machines at high level of reliability, some companies perform time-based preventive maintenance or age-based preventive maintenance to avoid sudden failure of machines. Usually, preventive maintenance tasks includes lubrication, cleaning, inspection, adjustment, alignment and/or replacement [25]. Even though above maintenance schemes may decline the probability of sudden downtime to some extent, high maintenance cost may be generated due to frequent “over maintenance”. Some companies hold lots of spare parts inventory in case the shortage of spare parts for maintenance actions. If the spares ordering is inappropriate, companies have to suffer high inventory quantity or high inventory holding cost. A widely accepted view of decreasing unnecessary cost, including maintenance cost, inventory cost and equipment failure loss, is to perform condition-based maintenance on critical components. Recently, condition based maintenance has been studied extensively as one of the most important maintenance method. To guarantee the effectiveness and economy of maintenance, a new failure probability estimation function is established based on a novel remaining useful life prediction using condition monitoring signal to date. The estimated failure probability is the basis of replacement determination which is related to jointly optimize replacement time and spare ordering. In terms of spare ordering, spares should be ordered at right time to trade off spares shortage cost and inventory holding cost. Therefore, the reasonable decisions for replacement and spare ordering should include when to perform replacement and purchase spare parts. All the decisions are based on accurate failure prediction. The main conChen X, Xu D, XiAo L. Joint optimization of replacement and spare ordering for critical rotary component based on condition signal to date. eksploatacja i niezawodnosc – Maintenance and Reliability 2017; 19 (1): 76–85, http://dx.doi.org/10.17531/ein.2017.1.11.