Determining of machine availability when taking the scheduled breaks during the recovery work

Abstract

Subject of research is a machine, which periodically operates. The operating cycle consists of the working shift and scheduled break. The repair of machine is performed immediately after the failure and continued to its recovery (the repair is carried out during the scheduled breaks). Article objective consists in the determination of dependence between the machine availability, operating time between failures, time to machine recovery and the duration of working shift and scheduled break. The processes of machine operation and recovery feature either deterministic or stochastic components. The dependence of the machine availability on the operating time between failures, time to recovery and fractions of time to machine recovery, which are accounted for the working shift, is determined. In addition, the dependences of the fractions of time to machine recovery (accounted for the working shift) on the distributive law of time to recovery, duration of working shift and scheduled break are defined. This enables to determine the availability in accordance with the indicated factors and operating time between failures. The numerical simulation of impact of the time to recovery and the duration of shifts and breaks on the fraction of average time to recovery, which is accounted for the working shift, is carried out. Simulation data with the time to recovery distributed in accordance with the exponential rule and Weibull law are presented. If the average time to machine recovery exceeds 50% of the operating cycle duration, the indicated fraction may be equated with the fraction of shift in the operating cycle.