SINCLAIR COMMUNITY COLLEGE

Dayton, Ohio

Final Exam QET 211 - Fall 2004


Question #1 Create a System function list, and a list of requirements for the following automatic filling system. (the material being added to the tank is a methyl alcohol solution) Consider the tank, controller, sensor, valve and pump. (25 pts.)

Question #2 Complete a fault tree analysis for our tank system with the fault being methyl alcohol solution not being contained. (25 pts.)

Question #3 Complete an overall System FMEA (30 pts.)

Question #4. (10 pts.)

Given the following data, calculate the probability for

a. A man living to be 50 years of age?
b. A man living 15 years after his 60th birthday?

t (in years)
 number

 0

1

5

10

20

30

40

50

60

70

75

80

85

90

95

99

1,023,102

1,000,000

983,817

971,804

951,483

924,609

883,342

810,900

677,771

454,548

315,982

181,765

78,221

21,577

3,011

125

Question #5 (10 pts.)
A space power reactor system consisting of a reactor, radiation shield, converter, radiator, and controls, is assumed to be functionally arranged in series, as any subsystem failure will result in overall system failure.

Failure rates are estimated as follows:

 Subsystem  Rate f/hr
 Reactor  5 x 10-7
 Shield  1 x 10-8
 Converter  2 x 10-7
 Radiator  2 x 10-7
 Controls  3 x 10-7

Find the system reliability for a seven year mission.

______________________________________________________

Extra Credit Question # 1. (10 pts.)

A device has a constant failure rate of 0.7 failures/year. What is the probability that the device will fail during the second year of operation?

Extra Credit Question #2. (10 pts.)

A National Guard unit is supplied with 20,000 rounds of ammunition that is 5 years old. The commander wants to check the quality of the rounds. He samples 200 rounds and test fires the ammunition. Twelve of the rounds misfire. Assuming that the misfires are random failures of the ammunition caused by previous storage conditions, estimate the MTTF in years. (Assume the exponential distribution).

Extra Credit Question #3. (10 pts.)

Assume that component reliability is .5 and we want system reliability of >.99. What is the minimum number of parallel components needed.