Problem: In the design of the F-35 Joint Strike Fighter, four major subsystems have been identified, each having a Weibull failure distribution with parameter values given in the following table:
|
Subsystem
|
Scale parameter, η, year
|
Shape parameter, β
|
|
Flight Control Computer
|
3.0
|
0.90
|
|
Avionics
|
4.5
|
0.81
|
|
Structures
|
5.5
|
1.82
|
|
Life Support
|
6.0
|
1.00
|
Assume that these subsystems will be operating serially. The reliability of the fighter must be 0.995 at the end of the first year.
(a) Determine the percentage increase in reliability for each subsystem needed in order to reach the fighter reliability goal. Assign equal reliability goals to each of the 4 subsystems.
(b) If active redundancy is the only means of achieving further reliability growth for each of the subsystems, what is the minimum number of redundant units of each necessary to achieve the component reliability goals?