Fatigue Design and Reliability


Book Description

This volume represents a selection of papers presented at the Third International Symposium on Fatigue Design, Fatigue Design 1998, held in Espoo, Finland, 26-29 May, 1998.One objective of this symposium series was to help bridge the gap that sometimes exists between researchers and engineers responsible for designing components against fatigue failure. The 21 selected papers provide an up-to-date survey of engineering practice and a preview of design methods that are advancing toward application. Reliability was selected as a key theme for FD'98. During the design of components and structures, it is not sufficient to combine mean material properties, average usage parameters, and pre-selected safety factors. The engineer must also consider potential scatter in material properties, different end users, manufacturing tolerances and uncertainties in fatigue damage models. Judgement must also be made about the consequences of potential failure and the required degree of reliability for the structure or component during its service life. Approaches to ensuring reliability may vary greatly depending on the structure being designed. Papers in this volume intentionally provide a multidisciplinary perspective on the issue. Authors represent the ground vehicle, heavy equipment, power generation, ship building and other industries. Identical solutions cannot be used in all cases because design methods must always provide a balance between accuracy and simplicity. The point of balance will shift depending on the type of input data available and the component being considered.




Fatigue Design


Book Description

Fatigue Design, Second Edition discusses solutions of previous problems in fatigue as controlled by their particular conditions. The book aims to demonstrate the limitations of some methods and explores the realism and validity of the resulting solutions. The text is comprised of four chapters that tackle a specific area of concern. Chapter 1 provides the introduction and covers the scope, level, and limitations of the book. Chapter 2 deals with the characteristics of design approach, and Chapter 3 talks about the prediction of fatigue life. The last chapter discusses the general factors in fatigue. The book will be of great interest to researchers and professionals concerned with fatigue analysis, such as engineers and designers.




Fatigue Testing and Analysis


Book Description

Fatigue Testing and Analysis: Theory and Practice presents the latest, proven techniques for fatigue data acquisition, data analysis, and test planning and practice. More specifically, it covers the most comprehensive methods to capture the component load, to characterize the scatter of product fatigue resistance and loading, to perform the fatigue damage assessment of a product, and to develop an accelerated life test plan for reliability target demonstration. This book is most useful for test and design engineers in the ground vehicle industry. Fatigue Testing and Analysis introduces the methods to account for variability of loads and statistical fatigue properties that are useful for further probabilistic fatigue analysis. The text incorporates and demonstrates approaches that account for randomness of loading and materials, and covers the applications and demonstrations of both linear and double-linear damage rules. The reader will benefit from summaries of load transducer designs and data acquisition techniques, applications of both linear and non-linear damage rules and methods, and techniques to determine the statistical fatigue properties for the nominal stress-life and the local strain-life methods. - Covers the useful techniques for component load measurement and data acquisition, fatigue properties determination, fatigue analysis, and accelerated life test criteria development, and, most importantly, test plans for reliability demonstrations - Written from a practical point of view, based on the authors' industrial and academic experience in automotive engineering design - Extensive practical examples are used to illustrate the main concepts in all chapters




Fatigue Design of Steel and Composite Structures


Book Description

This volume addresses the specific subject of fatigue, a subject not familiar to many engineers, but still relevant for proper and good design of numerous steel structures. It explains all issues related to the subject: Basis of fatigue design, reliability and various verification formats, determination of stresses and stress ranges, fatigue strength, application range and limitations. It contains detailed examples of applications of the concepts, computation methods and verifications.




Fatigue Design of Aluminum Components and Structures


Book Description

Focusing on the design challenges associated with using aluminum in such fatigue-critical applications as highway infrastructures, transportation vehicles, automotive suspension systems, and aircraft and machine parts, this reference gives the data and guidelines that mechanical and civil design engineers need to meet these challenges head on.




Fatigue Life Analyses of Welded Structures


Book Description

Avoiding or controlling fatigue damage is a major issue in the design and inspection of welded structures subjected to dynamic loading. Life predictions are usually used for safe life analysis, i.e. for verifying that it is very unlikely that fatigue damage will occur during the target service life of a structure. Damage tolerance analysis is used for predicting the behavior of a fatigue crack and for planning of in-service scheduled inspections. It should be a high probability that any cracks appearing are detected and repaired before they become critical. In both safe life analysis and the damage tolerance analysis there may be large uncertainties involved that have to be treated in a logical and consistent manner by stochastic modeling. This book focuses on fatigue life predictions and damage tolerance analysis of welded joints and is divided into three parts. The first part outlines the common practice used for safe life and damage tolerance analysis with reference to rules and regulations. The second part emphasises stochastic modeling and decision-making under uncertainty, while the final part is devoted to recent advances within fatigue research on welded joints. Industrial examples that are included are mainly dealing with offshore steel structures. Spreadsheets which accompany the book give the reader the possibility for hands-on experience of fatigue life predictions, crack growth analysis and inspection planning. As such, these different areas will be of use to engineers and researchers.




SAE Fatigue Design Handbook


Book Description

Covers, in a single source, current technologies and procedures on all of the major elements of fatigue design. Intended as a handbook for industrial use, this book describes the major elements of the fatigue design process and how those elements must be tied together in a comprehensive product evaluation. Using this handbook will save the design engineer time, while ensuring understanding of the important elements of the fatigue design process.




Robust Design Methodology for Reliability


Book Description

Based on deep theoretical as well as practical experience in Reliability and Quality Sciences, Robust Design Methodology for Reliability constructively addresses practical reliability problems. It offers a comprehensive design theory for reliability, utilizing robust design methodology and six sigma frameworks. In particular, the relation between un-reliability and variation and uncertainty is explored and reliability improvement measures in early product development stages are suggested. Many companies today utilise design for Six Sigma (DfSS) for strategic improvement of the design process, but often without explicitly describing the reliability perspective; this book explains how reliability design can relate to and work with DfSS and illustrates this with real–world problems. The contributors advocate designing for robustness, i.e. insensitivity to variation in the early stages of product design development. Methods for rational treatment of uncertainties in model assumptions are also presented. This book promotes a new approach to reliability thinking that addresses the design process and proneness to failure in the design phase via sensitivity to variation and uncertainty; includes contributions from both academics and industry practitioners with a broad scope of expertise, including quality science, mathematical statistics and reliability engineering; takes the innovative approach of promoting the study of variation and uncertainty as a basis for reliability work; includes case studies and illustrative examples that translate the theory into practice. Robust Design Methodology for Reliability provides a starting point for new thinking in practical reliability improvement work that will appeal to advanced designers and reliability specialists in academia and industry including fatigue engineers, product development and process/ quality professionals, especially those interested in and/ or using the DfSS framework.




Safety Factors and Reliability: Friends or Foes?


Book Description

Have you ever wondered where the safety factors come from? Why is it that deterministic analysis has reached a very sophisticated level, but in the end empirical factors are still needed? Is there a way to select them, rather than assigning them arbitrarily as is often done? This book clearly shows that safety factors are closely related with the reliability of structures, giving yet another demonstration of Albert Einstein's maxim that "It is incomprehensible that Nature is comprehensible". The book shows that the safety factors are much more comprehensible if they are seen in a probabilistic context. Several definitions of the safety factors are given, analytical results on insightful numbers are presented, nonprobabilistic safety factors are shown, as well as their estimates derived by the inequalities of Bienayme, Markov, Chebushev and Camp-Meidell. A special chapter is devoted to important contributions by Japanese experts. This volume will help to critically re-think the issue of safety factors, which can create a false feeling of security. The deterministic paradigm can be enhanced by incorporating probabilistic concepts wisely where they are needed without treating all variables as probabilistic ones. The book shows that there is a need of their integration rather than separation. This book is intended for engineers, graduate students, lecturers and researchers.




Metal Fatigue in Engineering


Book Description

Applied Optimal Design Mechanical and Structural Systems Edward J. Haug & Jasbir S. Arora This computer-aided design text presents and illustrates techniques for optimizing the design of a wide variety of mechanical and structural systems through the use of nonlinear programming and optimal control theory. A state space method is adopted that incorporates the system model as an integral part of the design formulations. Step-by-step numerical algorithms are given for each method of optimal design. Basic properties of the equations of mechanics are used to carry out design sensitivity analysis and optimization, with numerical efficiency and generality that is in most cases an order of magnitude faster in digital computation than applications using standard nonlinear programming methods. 1979 Optimum Design of Mechanical Elements, 2nd Ed. Ray C. Johnson The two basic optimization techniques, the method of optimal design (MOD) and automated optimal design (AOD), discussed in this valuable work can be applied to the optimal design of mechanical elements commonly found in machinery, mechanisms, mechanical assemblages, products, and structures. The many illustrative examples used to explicate these techniques include such topics as tensile bars, torsion bars, shafts in combined loading, helical and spur gears, helical springs, and hydrostatic journal bearings. The author covers curve fitting, equation simplification, material properties, and failure theories, as well as the effects of manufacturing errors on product performance and the need for a factor of safety in design work. 1980 Globally Optimal Design Douglass J. Wilde Here are new analytic optimization procedures effective where numerical methods either take too long or do not provide correct answers. This book uses mathematics sparingly, proving only results generated by examples. It defines simple design methods guaranteed to give the global, rather than any local, optimum through computations easy enough to be done on a manual calculator. The author confronts realistic situations: determining critical constraints; dealing with negative contributions; handling power function; tackling logarithmic and exponential nonlinearities; coping with standard sizes and indivisible components; and resolving conflicting objectives and logical restrictions. Special mathematical structures are exposed and used to solve design problems. 1978