Age Based and Partial Preventive Replacement Policies subject to Shocks

In this article, two systems subject to shocks occurring based on a non-homogeneous Poisson process (NHPP) and failure rate are analyzed. The first system is consisted of a single unit that partial preventive replacements (PPR) of lower indenture level components can be done. The second system is consisted of single unit with age based replacement policy (ABR). In PPR system, occurrence of a defeat causes system stopping and consequently system will be received minimal repairs and following the occurrence of a shock the system has received inspection. Also this system is replaced after time T preventively. In ABR system a defeat leads to unit stopping and accordingly the unit has received minimal repairs and after a shock has received inspection. This system is replaced at time T or at times less than T preventively, due to failure of unit. The systems will be replaced with new and the same types, so analysis done based on average cost rate. Two examples are studied and optimal replacement age which minimizes expected cost is obtained and according to results and comparison of models, some analyses are provided.