A design team has proposed a system where two components, R2 and R3 with reliabilities of 0.85 each, work in parallel. This parallel group is in series with component R1 (reliability 0.90) and R4 (reliability 0.90). What is the total system reliability?
Explanation
For complex systems with both series and parallel components, the approach is to first calculate the equivalent reliability of each parallel subgroup, and then treat those subgroups as single components in the main series calculation.
Other questions
What is the primary objective of maintenance and reliability within an organization?
What is the definition of reliability in the context of operations management?
A loan application process at the National Bank of Greeley involves three sequential clerks with individual reliabilities of 0.90, 0.80, and 0.99. What is the overall reliability of this system?
What is the term for the expected time between a repair and the next failure of a component or machine?
Twenty air-conditioning systems were operated for 1,000 hours. Two systems failed: one after 200 hours and the other after 600 hours. What is the product failure rate in terms of failures per unit-hour, FR(N)?
Twenty air-conditioning systems were operated for 1,000 hours. Two systems failed: one after 200 hours and the other after 600 hours. What is the Mean Time Between Failures (MTBF)?
What is the purpose of providing redundancy in a system?
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What are the two primary types of maintenance discussed in the text?
What is the term for the high failure rate observed early in the life of a product or process?
How does the traditional view of maintenance costs, as depicted in Figure 17.4(a), differ from the full cost view shown in Figure 17.4(b)?
Farlen & Halikman, a CPA firm, experiences printer breakdowns that cost an average of $300 each. The firm's history over 20 months is: 0 breakdowns for 2 months, 1 for 8 months, 2 for 6 months, and 3 for 4 months. What is the expected number of breakdowns per month?
For the Farlen & Halikman firm, the expected number of breakdowns is 1.6 per month, and each breakdown costs $300. A preventive maintenance contract is available for $150 per month, which would reduce the average breakdowns to one per month. Which option is more economical?
What is autonomous maintenance?
What does Total Productive Maintenance (TPM) combine with a strategic view of maintenance?
Which of the following is a key element included in Total Productive Maintenance (TPM)?
A new aircraft control system requires 98 percent reliability and consists of three components in series. If all three components are to have the same level of reliability, what individual reliability is required for each component?
A medical equipment manufacturer subjected 100 heart pacemakers to 5,000 hours of testing. Halfway through the testing (at 2,500 hours), 5 pacemakers failed. What was the percentage of failures?
One hundred heart pacemakers were tested. Five failed at the 2,500-hour mark. The test continued to 5,000 hours for the remaining units. What was the number of failures per unit-hour?
If a manufacturer of disk drives tests 10 units and records one failure at 10,000 hours and another at 25,000 hours, with the remaining 8 units running for the full 50,000-hour test, what is the total number of unit-hours of operating time?
A production process has three parallel paths with reliabilities of 0.95, 0.90, and 0.98. What is the reliability of this parallel process?
A system is composed of three components in parallel with reliabilities of 0.90, 0.95, and 0.85. What is the reliability of the system?
A medical control system has three components in series with reliabilities of 0.99, 0.98, and 0.90. What is the reliability of the system?
If a medical control system with a series reliability of 0.873 (from components 0.99, 0.98, 0.90) is reconfigured so the 0.98 and 0.90 components are in parallel with each other, and that parallel group is in series with the 0.99 component, what is the new reliability?
What is the primary characteristic of remedial maintenance that occurs when preventive maintenance fails?
Which of the following tactics is used for improving reliability?
Which of the following is considered a maintenance tactic?
In the continuum of repair capabilities shown in Figure 17.5, what happens as a firm moves from operator maintenance towards depot service (return equipment)?
If a system is composed of 100 interacting parts, and each part has a reliability of 99.5 percent, what is the approximate overall reliability of the system?
When is preventive maintenance considered economical for a process?
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What is the primary function of a computerized maintenance management system as illustrated in Figure 17.3?
Which company is cited in the text for keeping its delivery vehicles operating and looking like new for 20 years or more as an example of a famed maintenance strategy?
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What does the interdependency of operator, machine, and mechanic signify in the context of maintenance and reliability?
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An electronic processing unit contains 50 components in series. The average reliability of each component is 99.0 percent. What is the approximate overall reliability of the unit?
A testing process has 400 components in series, and the average reliability of each is 99.5 percent. What is the approximate overall reliability of the testing process?
Why might an electronic firm 'burn in' their products prior to shipment?
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At Orlando Utilities Commission (OUC), an unexpected outage of a power generator could cost the utility an additional amount per day of what range?
What is the result of the interdependency of good maintenance and reliability management on a firm's performance, according to Figure 17.1?
A key aspect of Total Productive Maintenance (TPM) is emphasizing the total cost of ownership when purchasing machines. What does this mean?
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