Mission Availability Modeling Methods for k/N(G) Fleet under Time Constraints

Under runtime and maintenance time constraints during a mission, a simple and efficient modeling method is presented to evaluate mission-availability of k/N(G) fleet. The diagrams describing the fleet operational process and mission-time are given to analyze the relationship of runtime and maintenance time between systems and the fleet. An analytical formula for n/N(G) fleet is deduced by using the formulas of system mission-availability. By combining analytical and simulation methods, a stochastic Petri net model for maintenance process of fleets is given, and the parameters of the model is calculated by combining the analytical formula. The mission-availability of k/N(G) fleet under time constraints is obtained by the simulation model with the parameters. A numerical example is given to illustrate the trends of mission-availability of k/N(G) fleet under operational time-limit or maintenance time-limit, respectively, and the mission-availability difference between time constraints and no time constraints.