LIFE CYCLE RELIABILITY ENGINEERING

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1 LIFE CYCLE RELIABILITY ENGINEERING Life Cycle Reliability Engineering. Guangbin Yang Copyright 2007 John Wiley &Sons, Inc. ISBN:

2 LIFE CYCLE RELIABILITY ENGINEERING Guangbin Yang Ford Motor Company JOHN WILEY & SONS, INC.

3 This book is printed on acid-free paper. Copyright 2007 by John Wiley & Sons, Inc. All rights reserved Published by John Wiley & Sons, Inc., Hoboken, New Jersey Published simultaneously in Canada. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, (978) , fax (978) , or on the web at Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) , fax (201) , or online at Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. For general information on our other products and services or for technical support, please contact our Customer Care Department within the United States at (800) , outside the United States at (317) or fax (317) Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic formats. For more information about Wiley products, visit our web site at Library of Congress Cataloging-in-Publication Data: Yang, Guangbin, Life cycle reliability engineering / Guangbin Yang. p. cm. Includes bibliographical references and index. ISBN-13: (cloth) ISBN-10: (cloth) 1. Reliability (Engineering) 2. Product life cycle. I. Title. TS173.Y dc Printed in the United States of America

4 To Ling, Benjamin, and Laurence

5 CONTENTS Preface xi 1 Reliability Engineering and Product Life Cycle Reliability Engineering, Product Life Cycle, Integration of Reliability Engineering into the Product Life Cycle, Reliability in the Concurrent Product Realization Process, 6 Problems, 7 2 Reliability Definition, Metrics, and Product Life Distributions Introduction, Reliability Definition, Reliability Metrics, Exponential Distribution, Weibull Distribution, Mixed Weibull Distribution, Smallest Extreme Value Distribution, Normal Distribution, Lognormal Distribution, 28 Problems, 31 vii

6 viii CONTENTS 3 Reliability Planning and Specification Introduction, Customer Expectations and Satisfaction, Reliability Requirements, Reliability Program Development, Reliability Design and Design for Six Sigma, 61 Problems, 64 4 System Reliability Evaluation and Allocation Introduction, Reliability Block Diagram, Series Systems, Parallel Systems, Mixed Configurations, k-out-of-n Systems, Redundant Systems, Reliability Evaluation of Complex Systems, Confidence Intervals for System Reliability, Measures of Component Importance, Reliability Allocation, 106 Problems, Reliability Improvement Through Robust Design Introduction, Reliability and Robustness, Reliability Degradation and Quality Loss, Robust Design Process, Boundary Definition and Interaction Analysis, P-Diagram, Noise Effects Management, Design of Experiments, Experimental Life Data Analysis, Experimental Degradation Data Analysis, Design Optimization, Robust Reliability Design of Diagnostic Systems, Case Study, Advanced Topics in Robust Design, 181 Problems, Potential Failure Mode Avoidance Introduction, 194

7 CONTENTS ix 6.2 Failure Mode and Effects Analysis, Advanced Topics in FMEA, Fault Tree Analysis, Advanced Topics in FTA, Computer-Aided Design Controls, 230 Problems, Accelerated Life Tests Introduction, Development of Test Plans, Common Stresses and Their Effects, Life Stress Relationships, Graphical Reliability Estimation at Individual Test Conditions, Analytical Reliability Estimation at Individual Test Conditions, Reliability Estimation at Use Condition, Compromise Test Plans, Highly Accelerated Life Tests, 326 Problems, Degradation Testing and Analysis Introduction, Determination of the Critical Performance Characteristic, Reliability Estimation from Pseudolife, Degradation Analysis with Random-Effect Models, Degradation Analysis for Destructive Inspections, Stress-Accelerated Degradation Tests, Accelerated Degradation Tests with Tightened Thresholds, Accelerated Degradation Test Planning, 364 Problems, Reliability Verification Testing Introduction, Planning Reliability Verification Tests, Bogey Testing, Sample Size Reduction by Tail Testing, Sequential Life Testing, Reliability Verification Using Prior Information, Reliability Verification Through Degradation Testing, 408 Problems, 410

8 x CONTENTS 10 Stress Screening Introduction, Screening Techniques, Design of Screen Plans, Principle of Degradation Screening, Part-Level Degradation Screening, Module-Level Screening, Module Reliability Modeling, Cost Modeling, Optimal Screen Plans, 435 Problems, Warranty Analysis Introduction, Warranty Policies, Warranty Data Mining, Reliability Estimation from Warranty Claim Times, Two-Dimensional Reliability Estimation, Warranty Repair Modeling, Warranty Cost Estimation, Field Failure Monitoring, Warranty Cost Reduction, 480 Problems, 482 Appendix: Orthogonal Arrays, Linear Graphs, and Interaction Tables 486 References 495 Index 511

9 PREFACE This decade has witnessed a rapid development of economic globalization characterized by international free trade and free flow of capital across countries. It is now common to see similar products from different countries in the same market at the same time. This competition is further intensified by customers immediate access to detailed information about products through the ubiquitous Internet. With little time and effort, customers can compare competing products in terms of features, cost, reliability, service, and many other factors. It is not surprising that the best-informed customers are the picky ones; they always choose the products that work best and cost least. To survive and grow in such a competitive business environment, manufacturers must deliver reliable products with more features, at lower cost, and in less time. In response to these market forces, manufacturers are challenging reliability professionals as well as providing opportunities to improve reliability, shorten design cycle, reduce production and warranty costs, and increase customer satisfaction. To meet these challenges, reliability professionals need more effective techniques to assure product reliability throughout the product life cycle. This book is designed to provide useful, pragmatic, and up-to-date reliability techniques to assure product reliability throughout the product life cycle, which includes product planning; design and development; design verification and process validation; production; field deployment; and disposal. In particular, we discuss techniques for understanding customer expectations, for building reliability into products at the design and development stage, for testing products more efficiently before design release, for screening out defective products at the production stage, and for analyzing warranty data and monitoring reliability performance in the field. The book is comprised of 11 chapters organized according to the sequence of the product life cycle stages. In Chapter 1 we describe briefly xi

10 xii PREFACE the concepts of reliability engineering and product life cycle and the integration of reliability techniques into each stage of the life cycle. Chapter 2 delineates the reliability definition, metrics, and product life distributions. In Chapter 3 we present techniques for analyzing customer expectations, establishing reliability targets, and developing effective reliability programs to be executed throughout the product life cycle. Chapter 4 covers methodologies and practical applications of system reliability modeling and allocation. Confidence intervals for system reliability are also addressed in this chapter. Chapter 5 is one of the most important chapters in the book, presenting robust reliability design techniques aimed at building reliability and robustness into products in the design and development phase. In Chapter 6 we describe reliability tools used to detect, assess, and eradicate design mistakes. Chapter 7 covers accelerated life test methods, models, plans, and data analysis techniques illustrated with many industrial examples. In Chapter 8 we discuss degradation testing and data analysis methods that cover both destructive and nondestructive inspections. In Chapter 9 we present reliability techniques for design verification and process validation and in Chapter 10 address stress screening topics and describe more advanced methods for degradation screening. The last chapter, Chapter 11, is dedicated to warranty analysis, which is important for manufacturers in estimating field reliability and warranty repairs and costs. The book has the following distinct features: ž It covers many new and practical reliability techniques, including customerdriven reliability target setting, customer-driven reliability allocation, reliability design using design for six sigma, robust reliability design, accelerated life tests with higher usage rates, accelerated life tests with tightened thresholds, destructive degradation testing and analysis, sample size reduction based on physical characteristics, degradation screening, two-dimensional warranty analysis, and many other techniques. ž Pragmatism is emphasized throughout the book. All reliability techniques described are immediately applicable to product planning, design, testing, screening, and warranty analysis. ž Examples and exercises deal with real-world applications. Although many problems have been from the automotive industry, other industries have essentially the same problems. ž The book closely relates reliability to customer satisfaction and presents reliability and quality techniques, such as quality function deployment and customer-driven reliability allocation, for improving customer satisfaction. ž We provide and review recent advances in important reliability techniques which researchers will find useful in new developments. ž Some 300 references, representing helpful resources for pursuing further study of the topics, are cited. The book is designed to serve engineers working in the field of reliability and quality for the development of effective reliability programs and implementation

11 PREFACE xiii of programs throughout the product life cycle. It can be used as a textbook for students in industrial engineering departments or reliability programs but will also be useful for industry seminars or training courses in reliability planning, design, testing, screening, and warranty analysis. In all cases, readers need to know basic statistics. I am indebted to a number of people who contributed to the book. Mr. Z. Zaghati, Ford Motor Company, encouraged, stimulated, and assisted me in completing the book. I am most grateful to him for his continuing support. I would like to specially acknowledge Dr. Wayne Nelson, a consultant and teacher in reliability and statistics. He gave me detailed feedback on parts of this book. In addition, Dr. Nelson generously shared with me some of his unpublished thoughts and his effective and valuable book-writing skills. A number of people provided helpful suggestions and comments on parts of the book. In particular, I am pleased to acknowledge Prof. Thad Regulinski, University of Arizona; Dr. Joel Nachlas, Virginia Polytechnic Institute and State University; Dr. Ming-Wei Lu, DaimlerChrysler Corporation; Prof. Fabrice Guerin and Prof. Abdessamad Kobi, University of Angers, France; and Dr. Loon-Ching Tang, National University of Singapore. I am also grateful for contributions from Dr. Vasiliy Krivtsov, Ford Motor Company. Over the years I have benefited from numerous technical discussions with him. I would also like to thank Prof. Hoang Pham, Rutgers University; Dr. Greg Hobbs, Hobbs Engineering Corporation; and Prof. Dimitri Kececioglu, University of Arizona, who all generously reviewed parts of the manuscript and offered comments. Finally, I would like to express my deep appreciation and gratitude to my wife, Ling, and sons Benjamin and Laurence. Their support was essential to the successful completion of the book. GUANGBIN YANG Dearborn, Michigan May 2006