Extended Optimal Replacement Policy for a Two-Unit System under Cumulative Damage Model  
Author Shey-Huei Sheu


Co-Author(s) Tzu-Hsin Liu; Zhe-George Zhang


Abstract In this article, we consider a system consisting of two major units (A and B), which is subject to two types of shocks that occur according to a non-homogeneous Poisson process. The probabilities of these two shock types are agedependent. Each type I shock causes a minor failure of unit A, which also results in an amount of damage to unit B. The damages to unit B are accumulated to trigger a preventive replacement or a corrective replacement action. In addition, a minor failure for unit B with cumulative damage of z will occur with probability π(z) at a unit A failure instant. A type II shock is a major one and the system is replaced at its occurrence. We consider a more general replacement policy where the system is replaced at age T, or at the time which the total damage to unit B exceeds a pre-specified level Z (but less than the failure level K) or at any type II shock or when the total damage to unit B exceeding a failure level K, whichever occurs first. The expected cost per unit time is formulated by introducing relative costs.


Keywords Cumulative damage model; Optimization; Shock model; Replacement policy
    Article #:  20124
Proceedings of the 20th ISSAT International Conference on Reliability and Quality in Design
August 7-9, 2014 - Seattle, Washington, U.S.A.