Seongwoo Woo Reliability Design of Mechanical Systems A Guide for Mechanical and Civil Engineers Second Edition Reliability Design of Mechanical Systems Seongwoo Woo Reliability Design of Mechanical Systems A Guide for Mechanical and Civil Engineers Second Edition 123 SeongwooWoo Reliability Association of Korea Seoul, Korea (Republicof) ISBN978-981-13-7235-3 ISBN978-981-13-7236-0 (eBook) https://doi.org/10.1007/978-981-13-7236-0 1stedition:©SpringerInternationalPublishingAG2017 2ndedition:©SpringerNatureSingaporePteLtd.2020 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpart of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission orinformationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar methodologynowknownorhereafterdeveloped. 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The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore Preface to the First Edition In the beginning of the twentieth century, new sophisticated mechanical systems such as bridges, rockets, automobiles, airplanes, and space shuttles were designed and built for people to live comfortable lives through the engineering design pro- cesses. Typical design process can be broadly summarized as (1) define the prob- lems,(2)developtheproduct–prototype,designandtesting,(3)production.Dueto the frequent occurrence of disasters for new products, product reliability has become one of increasingly important factors (to consider) because of cost, com- petition,publicdemand,andadaptationofnewtechnology.Themosteffectiveway to protect the reliability disaster is to develop the reliability-embedded design process including its methodology in parallel with the established design process. Asproductswithmultiplemodulesrequirehigherperformanceandmaterialcost reduction,thereliabilitydesignofproducthasbecomemorecomplexandincreases the risk of product failure. The studies of reliability engineering have been deep- enedtopreventthereliabilitydisastersofthepastcentury.Eventhoughtherearea large number of concepts, theory, and texts on reliability, an up-to-date book for emphasizing the new methodology of reliability design is still required to prevent the reliability disasters of the mechanical/civil system. From the standpoint of economics, company will decrease the operation profit forafailureinitsexpectedproductlifetimebecauseofProductLiabilityLawinthe global market. All products from tires to electric components are fabricated from the structure (or materials) that will tend to degrade or break down abruptly by randomloads.Themechanicalsystemcaneventuallyfractureduetofatiguewhich canresultfromcyclicalstresses(orloads).Whenproductsaresubjectedtorandom loads,theystartthevoidinmaterial(ordesigndefects),propagate,andruptureit.If failure for a new product happens, theproduct may nolonger meet theestablished specificationsforproperproductfunctionality.Toavoidproductfailureinlifetime, product should be designed to robustly withstand a variety of loads. The main objectives of writing this book are focused on explaining the devel- opment necessity of the reliability-embedded design process and its methodology. As reliability methodology, we will suggest the new parametric accelerated life testing(ALT)thatmeetsthosemarketrequirements—higherperformance,material v vi PrefacetotheFirstEdition cost reduction, and higher reliability in field. The reliability-embedded design process consists of parametric ALT plan, failure mechanism and design, acceler- ation factor, sample size equation, and the parametric ALT. It produces the relia- bility quantitative test specifications (RQ) in accordance with the reliability target. Aparametric ALT method therefore will assessthereliabilityof product subjected to repetitive stresses. Based on the market data, parametric ALT plan will set up the reliability target ofproductanditsmodules.Mechanicalsysteminfieldsubjectedtoloadsarisehow to design product for the failure mechanisms—fatigue and fracture. The accumu- lated damage in system like palmer miner rule can be represented at the time-to-failure model. The acceleration factor with a new effort concept (or loads) was derived from a generalized life-stress failure model. So the new sample size equation with the acceleration factor enabled the parametric ALT to quickly evaluate the expected lifetime of product. This parametric ALT should help an engineer to uncover the missing design parameters affecting reliability during the design process of new product. Consequently,ifappliedintheestablisheddesignprocess,newparametricALT helpscompaniestoimprovenewproductreliabilityandavoidtherecallsofproduct failuresinfield.Astheimproperdesignparametersinthedesignphaseareidentified bythisreliabilitydesignmethod,theproductwillimprovethereliabilitythatwillbe measuredbytheincreaseinlifetime,LB,andthereductioninfailurerate,k.Product will meet the reliability target in industry. This book will help to prevent the relia- bilitydisasterthroughtheparametricALT.WealsoprovidealotofparametricALT examples that are effective tobe understood in themechanical/civil field. This book is composed of nine chapters. Chapter 1 presents the present aspect andneedofreliabilityengineeringintheadvanceofmoderntechnology.Chapter2 reviews the historical reliability disasters and their root cause within the past cen- tury. It will explain the significance of reliability assessment, and its methodology needtopreventreliabilitydisastersinthedesignprocess.Chapter3willexplainthe most important fundamental definitions of statistics and probability theory, the mathematical essentials of reliability engineering, and the most significant aspects of reliability engineering developed within the past century. It will help one to understandthebasicconceptsofreliabilitymethodologiesthatwillbediscussedin Chap.8.Chapter4throughChap.6presentloadanalysis,stressconcept,andabrief overview of the typical reliability failure mechanism of product—fatigues and fractures.Chapter7willpresentthefundamentalconceptsoftheparametricALTin product that will be the core of this book. Chapter 8 will also present case studies that are useful in a variety of engineering areas. Chapter 9 will cover the future aspectsofparametric ALTinmechanicalproduct thatwillbedevelopedassystem engineering. This book is intended to introduce the prerequisite concepts of the parametric ALT for senior level undergraduate and graduate students, professional engineers, college and university level lecturers, researchers, and design managers of the engineering system. We hope this noble methodology explained in this book will PrefacetotheFirstEdition vii help to prevent the reliability disasters of new product in field. The authors would alsoliketothankSpringerforthepublishingofthiswork,especiallyMayraCastro, Springer DE. With their help, this book has been published. Seoul, Korea (Republic of) Seongwoo Woo Preface to the Second Edition Inthelastcentury,newsophisticated mechanicalsystemssuchasautomobiles and airplanes were designed and built to make human lives comfortable. Mechanical systems are required with higher performance and material cost reduction. As a result, the design of product has become more complex and increases the risk of product failure. As seen in modern mechanical products from tires to electric components, they assembled in one structure (or platforms). They will tend to degradebyavarietyofloadsandeventuallyfracture.Ifcloselylooked,theywould start the design defects in structure, propagate, and rupture it. If failure for new product happens, the product may no longer meet the company established speci- fications for proper product functionality and reject in marketplace immediately. Duetothefrequentrecallsfornewproducts,productreliabilityhasbecomeone ofthecriticalfactorsofproductdesignaswellaswithcostandquality.Thestudies ofmechanicalengineeringalsohavebeendeepenedtoreflectthedesignconceptsin thepastcentury.Toavoidproductfailureinlifetime,productshouldbedesignedto robustly withstand a variety of loads. Many engineers had to wonder why the product recalls often happen. They thought such possibility could be assessed: (1)mathematicalmodelinglikeNewtonianmethod,(2)thetimeresponseofsystem simulation for (random) dynamic loads, (3) the rainflow-counting method, and (4) Miner’s rule that the system damage could be estimated. However, because there are a lot of assumptions, this analytic methodology is exact but complex to reproduce the product failures due to the design flaws in product operation. Consequently, new parametric accelerated life testing method can be an alter- native to make better the reliability design of mechanical system. Based on the marketdata,parametricALTplanwillsetupthereliabilitytargetofproductandits modules. The acceleration factor with a new effort concept (or loads) was derived from a generalized life-stress failure model. So the new sample size equation with theaccelerationfactorenabledtheparametricALTtoquicklyevaluatetheexpected lifetime of product. This parametric ALT should help an engineer to uncover the missing design parameters affecting reliability and assess whether the target of the productreliabilityisachievedduringthedesignprocessofnewproduct.Asaresult, it produces the reliability quantitative (RQ) test specifications in accordance with ix x PrefacetotheSecondEdition thereliabilitytarget.AparametricALTmethodwillassessthereliabilityofproduct (or module) subjected to repetitive stresses. Theprimarypurposeofwritingthisbookinthefirsteditionwastofigureoutthe design problems of mechanical system and prevent them by parametric ALT. The firsteditionbookfocusedontheexactdescriptionofparametricALT.Severalcore concepts in each chapter seem to be missing that it is not easy for mechanical engineertoreadthisbook.Forexample,thereisvibration(ornoise)inmechanical systemthatcanbeoftenclaimedbycustomer.Thedynamicanalysisofmechanical system is modeled as mass in the form of the body, spring in the form of sus- pension, and damper in the form of shock absorbers. But we did not mention it in thefirstedition.Sometopicsinthesecondeditionaremodifiedandrewritten,many new topics are added, and several new features have been introduced. 1. The abstracts of each chapter will be restated at the beginning. Each topic in reliabilitydesignofmechanicalsystemsisself-contained,withallconceptsfully explained and the derivations presented in complete detail. 2. Thepresentationofsomeofthetopicsineachchapterismodifiedforexpanded coverage and better clarity. New topics in Chaps. 1, 4, 5, and 6 are presented. 3. AllnewtopicsrelatedtoproductdevelopmentprocesswillbeaddedinChap.1. To better understand the failure mechanics, design and reliability testing, reli- ability block diagram, and reliability testing will be included in Chap. 4. Fluid analysis and vibration will be added in Chap. 5. Chapter 6 will be included in the strength of product materials, failure analysis with modified example, and corrosion problem of product. Examples of reliability block diagram in mechanical product like automobile will be introduced in Chap. 7. Chapter 8 will be re-explained in detail with illustrative examples. Thisbookservesasanintroductiontothesubjectofthereliabilitydesignofthe mechanical system. It also will have some unique points: (cid:129) Widely used for senior-level undergraduate and graduate students, professional engineers, college- and university-level lecturers, researchers, and design managers in the field of mechanical and civil engineering. (cid:129) Uniqueinthenoblereliabilitymethodologyexplainedinthisbooktopreventit fromtheproductrecallsofnewmechanicalproductinthefieldslikeautomobile and airplane. (cid:129) Supplied with detailed case studies based on methodology of parametric ALT that will be obtained in the process of product developing and helpful to the mechanical/civil engineer. Seoul, Korea (Republic of) Seongwoo Woo Contents 1 Introduction to Reliability Design of Mechanical/Civil System . . . . 1 1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Development of Mechanical Product . . . . . . . . . . . . . . . . . . . . 6 1.2.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.2.2 Mechanical Engineering Design Process . . . . . . . . . . . . 7 Reference. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2 Product Recalls and Its Assessment Significance. . . . . . . . . . . . . . . 19 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2.2 Product Recalls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 2.2.1 Versailles Rail Accident in 1842. . . . . . . . . . . . . . . . . . 28 2.2.2 Tacoma Narrows Bridge in 1940 . . . . . . . . . . . . . . . . . 30 2.2.3 De Havilland DH 106 Comet in 1953. . . . . . . . . . . . . . 31 2.2.4 G Company and M Company Rotary Compressor Recall in 1981. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 2.2.5 Firestone and Ford Tire in 2000 . . . . . . . . . . . . . . . . . . 34 2.2.6 Toshiba Satellite Notebook and Battery Overheating Problem in 2007 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 2.2.7 Toyota Motor Recalls in 2009 . . . . . . . . . . . . . . . . . . . 35 2.3 Development of Reliability Methodologies in History. . . . . . . . 36 2.3.1 In the Early of 20s Century—Starting Reliability Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 2.3.2 In the World War II—New Electronics Failure in Military. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 2.3.3 In the End of World War II and 1950s—Starting the Reliability Engineering . . . . . . . . . . . . . . . . . . . . . . 43 2.3.4 In the 1960s and Present: Mature of Reliability Methodology—Physics of Failure (PoF) . . . . . . . . . . . . 47 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 xi