Please see attachment for more clarification on question 1
1. Find the system reliability from the figure below.
2. Consider a system of 6 pumps of which at least 4 must function properly for system success. Each pump has an 85% reliability for the mission duration. Determine reliability of the system.
3. Suppose each engine has CFR = 0.0038074. Assuming 3-out-of 4 structure, find the followings:
a) The reliability of the system at a given time t
b) The system MTTF
Find the system reliability from the figure below.
First work out the reliability of components connected in series which have a combined
reliability defined by the product of the individual component reliabilities
Thus we define
Next combine the reliabilities of any parallel combinations. Observe in the above we
have one parallel combination that is R_12 and R_345 in parallel
And thus total reliability of this parallel combination is
R_12345=1-(1-R_12 )(1-R_345 )=1-(1-0.72)(1-0.576)=0.88128
Then we obtain a simplified reliability diagram
Then R_12345 in series with R_6 can be replaced by a single reliability R_123456determined
as the product of reliabilities
Looking at system reliability by means of worked examples of component reliabilities in series and in parallel