View the step-by-step solution to:

ENG 622 Table 1 below shows failure data for 250 germanium chips, all of which failed during the test period. Calculate and plot the probability of...


ENG 622




Table 1 below shows failure data for 250 germanium chips, all of which failed during the test period. Calculate and plot the probability of failure (unreliability) and probability of success (reliability) as a function of time to failure.

Table 1 failure data for chips

Time to Failure (min) t
Cumulative Failures , n(t)
0 0
20 9
40 23
60 50
90 83
160 113
230 143
400 160
900 220
1200 235
2500 240
2500 250





Figure below shows a chemical system in which the temperature increases with the feed rate of flow-controlled stream A. Heat is removed by water circulation through a water cooled heat exchanger. Normal reactor temperature is 200F, but a catastrophic runaway will start if the temperature reached 300F. In view of this situation:

1. The reactor temperature is monitored (by TE/TT 714).
2. Rising temperature is alarmed at 225F (see Horn).
3. An interlock shuts off stream A at 250F, stopping the reaction (SV-1).
4. The operator can initiate the interlock by punching the panic switch (NC).

a) Construct the fault tree for this system.
b) Obtain the minimal cut sets.





Load and strength are normally distributed (units in thousand-pounds) as follows:

Load ~ Normal(35, 8);

Strength ~ Normal (85, 8)

Note: Normal (35,8) indicates a mean value of 35 and standard deviation of 8.

Calculate the safety factor and safety index of the structural design.

How would the standard deviation on load and strength change if safety index is limited to a value of 3?




Consider the following system where all components are active during the life of the systems.
Satisfactory operation occurs if all parts in any one path function.

Find the system reliability of this system.


Conventional way of radiation treatment was to target cancer cells while some of the healthy sells also get affected. The instrument to provide radiation treatment cost $2 million and it is 90% reliable. The new concept targets only the cancer cells and the equipment costs only $1.25 million with unknown reliability since the equipment has not been used. The design-engineers assign a reliability value of 0.98 assuming all of the assumptions are correct. If all of the assumptions are not correct (equal likely probability), reliability is estimated only about 0.8. Since liability cost is $20 million, the engineer faces a decision for the following two alternates:

• Capture the opportunity of accomplishing cost saving and high reliability
• Assure a reasonable reliability by the conventional design

Set up a decision tree and determine the expected total cost of both designs. Which design would you prefer?




A plate fin heat exchanger for truck is designed to cool high temperature and high pressure oil using high pressure water. This heat exchanger on a recent trip from Miami to Cleveland developed an oil leak and it contaminated water. The plate fin heat exchanger uses gaskets to separate oil and water paths. Since this unit is used in trucks, vibration should also be considered. Run a FMEA analysis and suggest the possible solution to avoid future failure.



ENG 622 Table 1 below shows failure data for 250 germanium chips, all of which failed during the test period. Calculate and plot the probability of failure (unreliability) and probability of success (reliability) as a function of time to failure. Table 1 failure data for chips Time to Failure (min) t Cumulative Failures , n(t) 0 0 20 9 40 23 60 50 90 83 160 113 230 143 400 160 900 220 1200 235 2500 240 2500 250
Background image of page 1
Figure below shows a chemical system in which the temperature increases with the feed rate of flow-controlled stream A. Heat is removed by water circulation through a water cooled heat exchanger. Normal reactor temperature is 200 ° F, but a catastrophic runaway will start if the temperature reached 300 ° F. In view of this situation: 1. The reactor temperature is monitored (by TE/TT 714). 2. Rising temperature is alarmed at 225 ° F (see Horn). 3. An interlock shuts off stream A at 250 ° F, stopping the reaction (SV-1). 4. The operator can initiate the interlock by punching the panic switch (NC). a) Construct the fault tree for this system. b) Obtain the minimal cut sets.
Background image of page 2
Show entire document

This question was asked on Apr 28, 2010.

Recently Asked Questions

Why Join Course Hero?

Course Hero has all the homework and study help you need to succeed! We’ve got course-specific notes, study guides, and practice tests along with expert tutors and customizable flashcards—available anywhere, anytime.

-

Educational Resources
  • -

    Study Documents

    Find the best study resources around, tagged to your specific courses. Share your own to gain free Course Hero access or to earn money with our Marketplace.

    Browse Documents
  • -

    Question & Answers

    Get one-on-one homework help from our expert tutors—available online 24/7. Ask your own questions or browse existing Q&A threads. Satisfaction guaranteed!

    Ask a Question
  • -

    Flashcards

    Browse existing sets or create your own using our digital flashcard system. A simple yet effective studying tool to help you earn the grade that you want!

    Browse Flashcards