chapter 12 maintainability and availability. 12.1 introduction availability analysis of the system...
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Chapter 12Maintainability 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 maintainabilityreliability 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
tetM 1)(
oT
12.2.6 Optimum replacement strategy
The total number of the times the component is replaced is given by
rm nnn
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
12.3 Availability
12.3.1 definition
3. Steady state availability
4. Inherent availability
5. Achieved availability
6. Operational availability
12.3.2 Availability Analysis
12.3.3 Development of model
12.3.4 system with single component
12.3.5 Series system
One repair person :
Two repairperson
12.3.6 Parallel system
One repair person
Two repair persons
22
2
10 2
2)(
PPA
12.4 Optimization Approach
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