Robust Design Methodology for Reliability: Exploring the Effects of Variation and Uncertainty

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.

Table of Contents:
Preface Acknowledgements About the Editors Contributors PART One METHODOLOGY 1 Introduction Bo Bergman and Martin Arvidsson 1.1 Background 1.2 Failure Mode Avoidance 1.3 Robust Design 1.4 Comments and Suggestions for Further Reading References 2 Evolution of Reliability Thinking – Countermeasures for Some Technical Issues Åke Lönnqvist 2.1 Introduction 2.2 Method 2.3 An Overview of the Initial Development of Reliability Engineering 2.4 Examples of Technical Issues and Reliability Countermeasures 2.5 Discussion and Future Research 2.6 Summary and Conclusions References 3 Principles of Robust Design Methodology Martin Arvidsson and Ida Gremyr 3.1 Introduction 3.2 Method 3.3 Results and Analysis 3.4 Discussion 3.5 Conclusions References PART Two METHODS 4 Including Noise Factors in Design Failure Mode and Effect Analysis (D-FMEA) – A Case Study at Volvo Car Corporation Åke Lönnqvist 4.1 Introduction 4.2 Background 4.3 Method 4.4 Result 4.5 Discussion and Further Research 4.6 Summary References 5 Robust Product Development Using Variation Mode and Effect Analysis Alexander Chakhunashvili, Stefano Barone, Per Johansson and Bo Bergman 5.1 Introduction 5.2 Overview of the VMEA Method 5.3 The Basic VMEA 5.4 The Enhanced VMEA 5.5 The Probabilistic VMEA 5.6 An Illustrative Example 5.7 Discussion and Concluding Remarks Appendix: Formal Justification of the VMEA Method References 6 Variation Mode and Effect Analysis: An Application to Fatigue Life Prediction Pär Johannesson, Thomas Svensson, Leif Samuelsson, Bo Bergman and Jacques de Maré 6.1 Introduction 6.2 Scatter and Uncertainty 6.3 A Simple Approach to Probabilistic VMEA 6.4 Estimation of Prediction Uncertainty 6.5 Reliability Assessment 6.6 Updating the Reliability Calculation 6.7 Conclusions and Discussion References 7 Predictive Safety Index for Variable Amplitude Fatigue Life Thomas Svensson, Jacques de Maré and Pär Johannesson 7.1 Introduction 7.2 The Load–Strength Reliability Method 7.3 The Equivalent Load and Strength Variables 7.4 Reliability Indices 7.5 The Gauss Approximation Formula 7.6 The Uncertainty Due to the Estimated Exponent β 7.7 The Uncertainty Measure of Strength 7.8 The Uncertainty Measure of Load 7.9 The Predictive Safety Index 7.10 Discussion Appendix References 8 Monte Carlo Simulation versus Sensitivity Analysis Sara Lorén, Pär Johannesson and Jacques de Mar´e 8.1 Introduction 8.2 Transfer Function 8.3 Example from an Industrial Context 8.4 Highly Nonlinear Transfer Function 8.5 Total Variation for Logarithmic Life 8.6 Conclusions References PART Three MODELLING 9 Model Complexity Versus Scatter in Fatigue Thomas Svensson 9.1 Introduction 9.2 A Statistical Model 9.3 Design Concepts 9.4 A Crack Growth Model 9.5 Partly Measurable Variables 9.6 Conclusions References 10 Choice of Complexity in Constitutive Modelling of Fatigue Mechanisms Erland Johnson and Thomas Svensson 10.1 Background 10.2 Questions 10.3 Method 10.4 Empirical Modelling 10.5 A Polynomial Example 10.6 A General Linear Formulation 10.7 A Fatigue Example References 11 Interpretation of Dispersion Effects in a Robust Design Context Martin Arvidsson, Ida Gremyr and Bo Bergman 11.1 Introduction 11.2 Dispersion Effects 11.3 Discussion References 12 Fatigue Damage Uncertainty Anders Bengtsson, Klas Bogsjöand Igor Rychlik 12.1 Introduction 12.2 Fatigue Review 12.3 Probability for Fatigue Failure – Safety Index 12.4 Computation of E [D(T )|k] and V [D(T )|k] 12.5 Non Gaussian Loads – Examples References 13 Widening the Perspectives Bo Bergman and Jacques de Maré 13.1 Background 13.2 Additional Engineering Perspectives on Reliability 13.3 Organizational Perspectives on Reliability 13.4 Industrialization of Robust Design Methodology 13.5 Adoptions of Fatigue Reliability Methodology 13.6 Learning for the Future References List of Abbreviations Index