Mechanics and Uncertainty E-Book

Maurice Lemaire

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 244

Veröffentlichungsjahr: 2014

Beschreibung

Science is a quest for certainty, but lack of certainty is the driving force behind all of its endeavors. This book, specifically, examines the uncertainty of technological and industrial science. Uncertainty and Mechanics studies the concepts of mechanical design in an uncertain setting and explains engineering techniques for inventing cost-effective products. Though it references practical applications, this is a book about ideas and potential advances in mechanical science.

Leseprobe

Table of Contents

Foreword

Preface

Introduction

I.1. Mechanics and uncertainty throughout history

I.2. Aims and outline of the book

Chapter 1 Understanding Uncertainty

1.1. Uncertainty and reality

1.2. Robustness and reliability

1.3. Designing for robust production

Chapter 2 Modeling Uncertainty

2.1. Random uncertainty

2.2. Uncertainty in behavior models

2.3. Uncertainty propagation

Chapter 3 Decision Support under Uncertainty

3.1. Decision support in design

3.2. Summary and conclusion

Bibliography

Index

First published 2014 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.

Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:

ISTE Ltd27-37 St George’s RoadLondon SW19 4EUUK

www.iste.co.uk

John Wiley & Sons, Inc.111 River StreetHoboken, NJ 07030USA

www.wiley.com

©ISTE Ltd 2014

The rights of Savera Tanwir and Harry Perros to be identified as the authors of this work have

been asserted by them in accordance with the Copyright, Designs and Patents Act 1988.

Library of Congress Control Number: 2014931646

British Library Cataloguing-in-Publication Data

A CIP record for this book is available from the British Library

ISBN 978-1-84821-636-5

Foreword

Industry requires innovation. Innovations are based on technologies, but while we often talk about product technologies (airplane, train, automobile, rocket, satellite, etc.), we rarely discuss the specific technologies involved in the design, testing and industrialization of these products, i.e. the skills involved in product development. This domain has undergone considerable progress in the past decade, with advances in modeling and simulation tools, highly instrumented tests and the use of supercomputers acting as motors for progress.

However, the complexity and multiplicity of the technical domains involved mean that the challenges of high-performance development, producing good results from the outset, are great indeed. Solutions must be found through the use of multiphysics, bringing together domains such as aerodynamics, solid mechanics, thermics and even acoustics. A statistical and probabilistic approach increases the reliability of results, and design methodologies are undergoing constant improvement, as demonstrated by current optimization applications.

The research aspect of design has undergone considerable progress in recent years. However, knowledge of the industrial skills and applications has not developed at the same speed. Significant developments have been made in process modeling for certain procedures, such as forging, casting and deep drawing, but significant work is still required in other domains, including machining, welding and surface treatments. Even more work will be required before suitable models are available for the whole routing for individual articles.

As vice president of the Association Française de Mécanique (AFM), French Mechanics Association, I launched a discussion of this situation with colleagues within the association in 2009. My basic premise was this: that while research aspects were undergoing rapid development, production planning was being left behind. We needed to find a way for the groups responsible for these aspects to work together to develop appropriate solutions. My colleagues at the AFM introduced me to a specialist in industrialization research, Régis Bigot, Professor at the Ecole Nationale Supérieure d’Arts and Métiers, Metz, who I met in 2009. We discussed the subject and its scientific and industrial implications at some length, identifying a number of researchers working in this domain from across France; we invited these experts to participate in a meeting at the Maison de la Mécanique mechanics center. To my surprise, our invitation was accepted by researchers from seven different laboratories (Metz, Bordeaux, Clermont-Ferrand, Mulhouse, Compiègne, Troyes and Valenciennes), and a number of intense and detailed discussions took place, finally leading to the creation of a focus group which continued to operate over the course of the following two years.

Through the initiative of Maurice Lemaire, a team, whose members are listed in the Preface, set to work on understanding uncertainty, describing the main modeling tools available and exploring the decision-making process as related to this context. The results of their observation are presented in this book, with the aim of guiding those who wish to contribute to develop knowledge and skills in the field of industrialization.

For me, three main points stood out from our meetings:

– We spent a full half-day session discussing the meaning and precise definitions of terms (notably “uncertain” and “uncertainty”); terminology definition is often an important step.

– An increasing awareness of the place of “uncertainty” in the technical domain: in terms of product development, mastery of uncertainty is lost wherever our knowledge of any aspect is incomplete.

– Finally, we were fortunate to be able to present our work to the wider mechanics community at the Journee de I’AFM conference in April 2010, a source of great satisfaction for a new cross-disciplinary group.

This book is the fruit of our reflection, and we hope for innovations that will provide new solutions in the complex domains of industrialization.

Jean-Marc THÉRETPresident, AFM - 2010-2013February 2014

Preface

The purpose of this preface is to provide readers with background information on the source of this book and to thank my colleagues involved in bringing this project to fruition.

This book is the result of an initiative launched by the Association Française de Mécanique (AFM), the French Mechanics Association. The AFM gathers those involved in the field of mechanics, based on three areas: science, technology and industry.

Over the centuries, mechanical science has developed through the construction of models, which, until the 19th Century, were thought to have considerable predictive validity, as seen in their application to celestial mechanics, where such models provide perfect results due to the infinitely small duration of observations in relation to cosmic time-scales. Later, the concept of perfect deterministic models began to break down, forcing researchers to take a scientific approach to uncertainty.

Mechanical technologies are the result of man’s creative abilities, and are, to a certain extent, subject to chance, as their robustness and reliability can never be fully guaranteed. The performance of these technologies is therefore subject to uncertainty, and developers seek the best possible balance between the desired outcome and the cost of potential losses.

The mechanics industry implements technologies for design and production purposes. The design cycle, the production process and the life cycle of a product, as perceived by the user, are also subject to an environment for which the pre-existing information is incomplete. Uncertainty is also present in the components and systems of industrial projects. It can, additionally, come from the organization and its levels of resilience.

The first scientists to experience uncertainty in mechanics were undoubtedly those working on natural forces (such as earthquakes and storms), followed by those working on natural materials, such as soil. The awareness of uncertainty in structural mechanics and in design and production came later, and researchers needed to find ways to respond to the need for robust and reliable designs which go beyond the simple, but essential, manufacturing quality control.

Through the initiative of the AFM, I was invited to participate in a working group on “designing for robust production”, led by Jean-Marc Théret and Régis Bigot, which brought together researchers from across the field of mechanics. The group identified vocabulary as a primary reason for uncertainty, both in methodology and in the description of objectives. For this reason, the decision was taken to create a document to precisely specify these concepts, introducing readers to a variety of methods, their strengths and their limitations. In the course of our discussions, participants were encouraged to explore and explain their thoughts in as much depth as possible, providing contributions that were then discussed and integrated into a homogeneous report.

I wish to thank these participants (in order of their appearance in the text):

– Jean-Yves Dantan for his remarks on sections 1.1.1 and 2.3.2.2.3, and his contribution to section 1.3, entitled Designing for robust production, through discussions with Régis Bigot and Alain Etienne.

Jean-Yves Dantan and Régis Bigot are Professors and Alain Etienne is an Assistant Professor at the Ecole Nationale Supérieure d’Arts et Métiers in Metz.

– Thierry Yalamas for his contributions to section 1.3.5.

Thierry Yalamas is an Associate Director of Phimeca Engineering S.A. in Paris.

– Nicolas Gayton for his contributions to discussions of section 1.2, entitled Robustness and reliability, section 1.3.3.1 concerning capabilities and contributions to the section on Kriging methods (i.e. section 2.3.3.2).

Nicolas Gayton is an Assistant Professor and research supervisor at the IFMA in Clermont-Ferrand.

– Sébastien Castric for his contribution to discussions of section 2.1.2.2 concerning quantitative approaches to random uncertainty and for his contribution to section 2.2, entitled Uncertainty in behavior models.

Dr. Sébastien Castric is a visiting researcher and Assistant Professor at the UTC in Compiègne. He has recently taken on training responsibilities for Airbus.

– Sébastien Berger for his contributions on polynomial chaos, sections 2.1.4 and 2.3.2.4.

Sébastien Berger is a Professor at the INSA’s Val de Loire center in Blois.

– Felipe Aguirre for rereading section 2.1.2.2 on quantitative approaches to random uncertainty and sections 2.3.2.2.1 and 2.3.2.3 on Possibilistic models.

Dr. Felipe Aguirre is a research and development engineer at Phimeca Engineering S.A. in Paris.

– Cécile Mattrand for rereading section 2.2.2.5.1 on Markov processes.

Cécile Mattrand is an Assistant Professor at the IFMA, Clermont-Ferrand

– Jean-Marc Bourinet for his contribution on support vector machines (SVM), section 2.3.3.1.

Jean-Marc Bourinet is an Assistant Professor at the IFMA, Clermont-Ferrand.

– Vincent Dubourg for his contributions on Kriging methods, section 2.3.3.2.

Dr. Vincent Dubourg is a research and development engineer at Phimeca Engineering S.A. in Clermont-Ferrand.

– Jean-Luc Dulong for his contributions on the question of model reduction, section 2.3.4.

Jean-Luc Dulong is an Assistant Professor at the UTC, Compiègne.

– Yann Ledoux and Patrick Sébastian for their contributions to section 3.1, entitled Decision support in design.

Yann Ledoux is an Assistant Professor at the University of Bordeaux-1.

Patrick Sébastian is an Assistant Professor and research supervisor at the University of Bordeaux-1.

– Jean-Marc Théret for his contributions to the conclusion, section 3.2.1.2.6, concerning the TRL scale.

Jean-Marc Théret is the vice-president of Messier-Bugatti-Dowty, Paris.

The beginning of each contribution is indicated by a footnote and the end is marked by the symbol in the text.

I also wish to thank my colleague and friend André Lannoy of the Institut de Maîtrise des Risques (IMdR) for his valuable contributions in rereading and commenting on the preparatory document.

This list is not exhaustive, but it is sufficiently representative to show the conceptual and methodological aspects of uncertainty in mechanics. We hope that this book will help those involved in mastering uncertainty in mechanics to position their research and other activities within the broader, multidisciplinary context of the domain.

Maurice LEMAIRE

February 2014

Introduction

The title of this book “Mechanics and Uncertainty” joins these two terms, which are rarely encountered together. Mechanics is “a science, a technology and an industry” focusing on the study of movement, deformation and the states of equilibrium of systems. Uncertainty is a philosophical concept, often associated with questions concerning the nature of mankind and our destiny, but also with human creations. The convergence of science and uncertainty constitutes an acceptance of the impossibility of a deterministic predictive model, and our obligation to consider mechanical science in relation to uncertainty.

Here we will consider the history of our topic and the contributions made by a number of great thinkers, before providing a detailed overview of the contents of this book.

I.1. Mechanics and uncertainty throughout history

Confronted with the risks generated by natural disasters and by its own technical innovations, mankind began by turning to the gods. In 1722 BC, Hammurabi promulgated a code establishing sanctions of an eye for an eye, a tooth for a tooth in cases where users fell victim to construction faults. Over time, progress in reasoning, and in the calculation and observation of the natural world resulted in the replacement of the sanction principle by the idea of the predictability of events, modeled by mathematical algorithms, and the definition of their acceptability. In 1609, for example, Kepler published his famous set of laws establishing the elliptical trajectory of the planets around the Sun. In 1638, this was followed by Galileo’s discourses on two new sciences, which constituted an introduction to modeling in mechanics. The success of these theories led many thinkers to believe that nature could be reduced to a set of mathematical expressions by the construction of increasingly precise models, and works continued in this regard until a point, at the end of the 19th Century, where science appeared to be more or less “finished”.