Modeling and Analysis of the Reliability of Systems with One-shot Items

This article deals with modelling and analysis of the reliability of complex systems that use one-shot items during their operation. It includes an analysis of the impact of the reliability of used one-shot items on the resulting reliability of the system as a whole. Practical application of theoretical knowledge is demonstrated on an example of a model of reliability of an aircraft gun that was used for optimization of the gun's design during its development and designing. The analyzed gun uses two types of one-shot items - rounds intended for the conduct of fire and special pyrotechnic cartridges designed for re-charging a gun after a failure of the round. A proposed model enables us to analyze the responsiveness of the whole system due to a change of reliability of rounds and pyrotechnic cartridges and a change of the number of used rounds and pyrotechnic cartridges. This article demonstrates utilization of a proposed model to determine an optimum number of pyrotechnic cartridges that will achieve a required probability of fulfilment of mission with the given reliability of individual subsystems of the gun, rounds and pyrotechnic cartridges. Proposed procedures of modelling and analysis of the reliability of complex systems with one-shot items were used in practice in designing and development of the PL-20 aircraft gun. Development of the gun was successfully finished in 2005, and the gun was fielded in the armament of the Czech Republic Air Force.