Exam 16: Maintenance and Reliability

A product has four components A, B, C, and D. The finished product must have a reliability of at least .95. The first three components come from a supplier, and they have reliabilities of .99, .98, and .995, respectively. The fourth component is being designed now. What must the reliability of component D be in order to meet the product reliability condition?

Tiger Island Fabricators, which builds offshore oil platforms, has been experiencing problems with its profiling machine, a computer-driven device that cuts the ends of pipe so that they can be welded to another pipe, as shown in the data below. Each time a machine breaks down, the company loses about $3,000. If the company implements preventive maintenance, it will be able to reduce the number of breakdowns by 50%. What is the maximum that preventive maintenance can cost so that it becomes the preferred option?

A product is composed of a series connection of four components with the following reliabilities. What is the reliability of the system?

Preventive maintenance is reactive.

A product has three components X, Y, and Z. Product X has reliability of 0.991, and Y has reliability of 0.993. If Z has reliability of 0.991, what is the reliability of the entire product? Can Z be redesigned to be reliable enough for the entire product to have reliability of 0.99? Explain.

What is FR(N)? How is it calculated? How are FR(N) and MTBF related?

Given the following data, find the expected breakdown cost. The cost per breakdown is $200.

A system is composed of four parts, J, K, L, and M. All four must function for the system to function. The four component reliabilities are .99, .98, .992, and .998. The designers are considering putting an 80% reliable backup at K. This backup will change the system reliability from ________ to ________.

As the number of components in a system connected in a series increases, all other things being equal, the reliability of the system usually:

A system is composed of three components A, B, and C. All three must function for the system to function. There are currently no backups in place. The system has a reliability of 0.966. If a backup is installed for component A, the new system reliability will be:

A manager is comparing the total maintenance (preventive plus breakdown) cost curves for two scenarios. The graphs have maintenance commitment on the x-axis and costs on the y-axis. Scenario A includes the direct breakdown maintenance costs, while Scenario B includes the "full" (direct and indirect) breakdown maintenance costs. Which of the following should the manager notice when going from Scenario A to Scenario B?

A system has four components in a series. What is the reliability of the system?

Is there an optimal amount of preventive maintenance? What caution should be exercised before calculating this optimal amount?

How is MTBF related to FR(N)?

Sophisticated sensors in a maintenance system can detect:

When identifying the optimal maintenance policy, the cost of inventory maintained to compensate for the downtime is a cost often ignored.

Define reliability.

Define maintenance.

MTBF measures the average: