Tempo de sobrevida em transportadores de granéis sólidos em um porto da região nordeste

Abstract

The objective of this research was to estimate the survival of a group of industrial port equipment called solid bulk conveyors, thus contributing to decision making of the maintenance process. This study was carried out in the area of unloading of wagons and shipment of ore from the Port Maritime Terminal located on the coast of the state of Maranhão. The outcome was the time, in hours, until the equipment failure. The covariates of interest for comparison of the survival curves were: (i) the work shift, divided into (shift 1, shift 2 and shift 3); (ii) equipment of origin classified as (wagon turners, recovery or recovery forklift); (iii) types of ore divided into (Sinter, Granulate, Pellet Feed or Manganese); (iv) the types of failures considered for the study will be (probe, emergency key, tear and overload detector) (v) and the operating area, classified as (discharge and shipment of ore). The Kaplan-Meier method was used to estimate the overall survival probability and the curves were compared using the logrank test. The effect of each covariant on the survival time of the transporters was analyzed using the Cox regression model and for which the residue analysis and influential observations were performed. The 75% survival probability of the bulk material handling system is equivalent to an operational availability time of 444 hours. It was observed that of the 95 carriers evaluated, 38 (40%) failed and 57 (60%) were censored until the end of the study. The results show a significant decrease in the probability of survival of the equipment during the operating time, besides the significant difference between the survival curves of the covariables shift, types of ores, number of wagons and tons moved, indicated that they are important predictors in the Cox regression model. This research presented an original contribution to the literature, being the first study to investigate the risk factors associated with equipment failures used in the Maritime Terminal of Ponta da Madeira through the analysis of survival.