206
input
~
output
Figure 4.13. Figure 4.11 block diagram further simplified.
Chapter 4
input
~ output
Figure 4.14. Final simplification for Fig. 4.11 block diagram.
Compute reliability from Fig. 4.14 for A(1), A(2) in simple partial
parallel from Eq. (4.23). Reliability of components in series and parallel
with constant rates of failure with constant rate of failure are treated.
D. Reliability of Series Components
The reliability of the series components is
(4.24)
i=1
with a constant rate of failure
Rs = exp[-21 t] exp[-22t].., exp[-2,t]
(4.25]
Rs = exp[-Z2it]
for the above expression to hold:
1. The system reliability configuration must truly be a series one
2. The reliabilities
of the components must be independent
3. The components must be governed by a constant-hazard rate
model
The MTTF is
1
1
MTTF = ~ 2n = 21 + 22 -I- . . . + ,~n
(4.26)
i=1