Lecture Operations management - Chapter 4S: Reliability. After completing this unit, you should be able to: Define reliability, perform simple reliability computations, explain the term availability and perform simple calculations. | Reliability McGraw-Hill/Irwin Copyright © 2012 by The McGraw-Hill Companies, Inc. All rights reserved. You should be able to: Define reliability Perform simple reliability computations Explain the purpose of redundancy in a system 4S- Student Slides Reliability The ability of a product, part, or system to perform its intended function under a prescribed set of conditions Reliability is expressed as a probability: The probability that the product or system will function when activated The probability that the product or system will function for a given length of time Student Slides 4S- Finding the probability under the assumption that the system consists of a number of independent components Requires the use of probabilities for independent events Independent event Events whose occurrence or non-occurrence do not influence one another 4S- Student Slides Rule 1 If two or more events are independent and success is defined as the probability that all of the events occur, then | Reliability McGraw-Hill/Irwin Copyright © 2012 by The McGraw-Hill Companies, Inc. All rights reserved. You should be able to: Define reliability Perform simple reliability computations Explain the purpose of redundancy in a system 4S- Student Slides Reliability The ability of a product, part, or system to perform its intended function under a prescribed set of conditions Reliability is expressed as a probability: The probability that the product or system will function when activated The probability that the product or system will function for a given length of time Student Slides 4S- Finding the probability under the assumption that the system consists of a number of independent components Requires the use of probabilities for independent events Independent event Events whose occurrence or non-occurrence do not influence one another 4S- Student Slides Rule 1 If two or more events are independent and success is defined as the probability that all of the events occur, then the probability of success is equal to the product of the probabilities of the events 4S- Student Slides Though individual system components may have high reliabilities, the system’s reliability may be considerably lower because all components that are in series must function One way to enhance reliability is to utilize redundancy Redundancy The use of backup components to increase reliability 4S- Student Slides Rule 2 If two events are independent and success is defined as the probability that at least one of the events will occur, the probability of success is equal to the probability of either one plus minus that probability multiplied by the other probability 4S- Student Slides Rule 3 If two or more events are involved and success is defined as the probability that at least one of them occurs, the probability of success is 1 - P(all fail). 4S- Student Slides In this case, reliabilities are determined relative to a specified length of time. This is a common .
