An accelerated life test plan for a two-component parallel system under ramp-stress loading using masked data

摘要

Purpose - Most of the literature on the design of accelerated life test (ALT) plan focus on a singlesystem (subsystem) totally disregarding its internal configuration. Many a times it is not possibleto identify the components that cause the system failure or that the cause can only be identified by asubset of its components resulting in a masked observation. The purpose of this paper is to dealwith the planning of ramp-stress accelerated life testing for a high-reliability parallel systemcomprising two dependent components using masked failure data. Such a testing may prove to beuseful in a twin-engine aircraft. A ramp-stress results when stress applied on the system increases linearlywith time.Design/methodology/approach - A parallel system with two dependent components is taken withdependency modeled by Gumbel-Hougaard copula. The stress-life relationship is modeled using inversepower law, and cumulative exposure model is assumed to model the effect of changing stress. The method ofmaximum likelihood is used for estimating design parameters. The optimal plan consists in finding optimalstress rate using D-optimality criterion.Findings - The optimal plan consists in finding optimal stress rate using D-optimality criterion byminimizing the reciprocal of the determinant of Fisher information matrix. The proposed plan has beenexplained using a numerical example and carrying out a sensitivity analysis.Originality/value - The model formulated can help reliability engineers obtain reliability estimates quicklyof high-reliability products that are likely to last for several years.