Selective maintenance is often applied in many industrial environments where maintenance is performed between sequence missions. When the mission time is stochastic and there are multiple maintenance workers with different capacities, the system reliability of the next work mission can be maximized by using a stochastic model under the constraint of the limit maintenance time.The optimal maintenance strategy is obtained with an optimization algorithm. A simulation was performed to verify the validity and feasibility of the proposed model. KEYWORDS group maintenance, maintenance time, mission time, stochastic model, stochastic selective maintenance
INTRODUCTIONAfter the wisdom of China was presented, cyber-physical systems, 1 cloud computing, wireless networks, 2 big data, Vehicular Network, 3,4 Industrial Intelligence Management, etc, have developed rapidly. In the proper and safe operation of industrial and military equipment, transportation systems maintenance is very important. 5 Maintenance management can establish reasonable maintenance policies for complex systems to meet new design requirements with using reliability and maintenance engineering analyses, such as equipment reliability and maintainability, in order to realize timely and effective maintenance to ensure the performance of the system with the lowest resource consumption. 6In many industrial fields (eg, manufacturing systems, military equipment systems, and power generation systems), maintenance is performed between two continuous missions. Each component or equipment can be repaired in different ways, such as no maintenance, minimal maintenance, preventive maintenance, and replacement. However, all maintenance tasks are not fully performed because of limited resources, such as maintenance time, cost, tools, and maintenance workers, 7 so part of the maintenance tasks are executed to maximize the system reliability of the next work mission. This is called selective maintenance. The workflow of selective maintenance is shown in Figure 1.Unlike the deterministic selective maintenance, a feasible deterministic maintenance set cannot be obtained in the stochastic selective maintenance because of the stochastic maintenance time or work time. For different systems, many different models are defined. Cassady et al 7 defined selective maintenance and a mathematical programming model for a two-state system. Cassady et al 8 developed a model that maximizes the system reliability with maintenance time Constraints for a series-parallel system with two-state components. In the model, the lifespan of a component follows a Weibull distribution, so that this reliability function is influenced by the age of components at the beginning of the mission and the mission time. Zhu et al 9 established a time-constrained Concurrency Computat Pract Exper. 2019;31:e4840. wileyonlinelibrary.com/journal/cpe
