O'Reilly logo

Reliability, Maintainability and Risk, 9th Edition by David J. Smith

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Appendix 8

Answers to Exercises

Chapter 2

(a) (b)
1. 114
1.1
2. 0.99
0.42 (0.12* )
3. 10–5
10–3
4. 2.2 × 10–3
0.18 (0.22* )
5. Negligible
Negligible
6. Unavailability × 2
Unavailability × approx 2

* Beware the approximation. λt is large (i.e. 0.876). Furthermore, if the 10 000 hr per year approximation were used, then λt = 1.

Chapter 5

1. Accumulated time T = 50 × 100 = 5000 hr. Since the test was time truncated n = 2(k + 1).
Therefore,
(a) n = 6, T = 5000, α = 0.4. From Appendix 2, χ2 = 6.21

MTBF60%=2Tχ2=100006.21=1610hr

(b) n = 2, T = 5000, α = 0.4. From Appendix 2, χ2 = 1.83

MTBF60%=2Tχ2=100001.83=5464

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required