Asked by Mulham Shbeib on Jul 07, 2024
Verified
Consider a product that is "settled in." Its MTBF distribution has been found to be normal with a mean of 1,000 hours and a standard deviation of 250 hours. What is the probability of a breakdown before 750 hours? Before 500 hours? Would you prefer a policy of preventive maintenance, or a policy of breakdown maintenance, on this product? Explain your choice.
Preventive Maintenance
Maintenance activities performed regularly on equipment before faults occur, aimed at reducing the risk of unexpected breakdowns and downtime.
Breakdown Maintenance
The practice of repairing or fixing equipment and machinery only after it has failed or broken down, as opposed to performing regular preventative maintenance.
MTBF Distribution
MTBF (Mean Time Between Failures) Distribution is a statistical representation of the expected performance or reliability of a system, indicating the average time between failures.
- Apply normal distribution to determine the probability of system failure before a specified time.
- Evaluate and decide between preventive maintenance and breakdown maintenance strategies.
Verified Answer
KB
KANDA BALJINDER-SINGHJul 08, 2024
Final Answer :
Failure probabilities are not negligible. The value 750 hours is one standard deviation away from the mean, and the area under the normal curve left of that point is 0.15866. The value 500 hours is two standard deviations away, and the area representing failure is 0.02275. Most students will opt for breakdown maintenance. The standard deviation is relatively large compared to the mean; preventive maintenance would have to be performed relatively early and often.
Learning Objectives
- Apply normal distribution to determine the probability of system failure before a specified time.
- Evaluate and decide between preventive maintenance and breakdown maintenance strategies.