Chapter 12 Maintainability and Availability 12 1 introduction

Chapter 12 Maintainability and Availability

12. 1 introduction Availability analysis of the system requires a knowledge: (1) How the components are functional connected. (2) The failure process of the component. (3) The method of operation and the definition of the failure. (4) The repair or maintenance police.

12. 2 Maintainability 12. 2. 1 Concept Maintainability M(t) : the probability of repairing a failed component or system in a specified period of time. Two kinds: Preventive maintainability Corrective maintainability

12. 2. 2 Preventive maintainability reliability of the system

System Reliability

Example 12. 2 derive the condition under preventive maintenance is beneficial to the

12. 2. 3 imperfect maintenance

12. 2. 4 Repair time distribution

12. 2. 5 Unrepaired failure Number of unrepaired failure in time

12. 2. 6 Optimum replacement strategy The total number of the times the component is replaced is given by

12. 2. 7 Spare parts requirement The probability of having n failure in time t :

Example 12. 9 Three kind of component in an system : 20 in type A (failure rate 0. 002), 130 in type B (failure rate 0. 0001), and 100 in type C (failure rate 0. 0005). Find the number of spare parts required to cover the mission period 30 days and 99 percent of probability