Which Replacement Is Better at Working Cycles or Number of Failures

Satoshi MIZUTANI  Xufeng ZHAO  Toshio NAKAGAWA  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E103-A   No.2   pp.523-532
Publication Date: 2020/02/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.2019EAP1049
Type of Manuscript: PAPER
Category: Reliability, Maintainability and Safety Analysis
Keyword: 
replacement policies,  minimal repair,  working cycle,  replacement last,  replacement overtime,  

Full Text: FreePDF(906.2KB)


Summary: 
When a unit repeats some works over again and undergoes minimal repairs at failures, it is more practical to replace it preventively at the end of working cycles or at its failure times. In this case, it would be an interesting problem to know which is better to replace the unit at a number of working cycles or at random failures from the point of cost. For this purpose, we give models of the expected cost rates for the following replacement policies: (1) The unit is replaced at a working cycle N and at a failure number K, respectively; (2) Replacement first and last policies with working cycle N and failure number K, respectively; (3) Replacement overtime policies with working cycle N and failure number K, respectively. Optimizations and comparisons of the policies for N and K are made analytically and numerically.