Control of welding distortion in thin-plate fabrication Related titles: Self-piercing riveting (ISBN 978-1-84569-535-4) Understanding biocorrosion (ISBN 978-1-78242-120-7) Handbook of smart coatings for materials protection (ISBN 978-0-85709-680-7) WoodheadPublishingSeriesinWeldingandOther JoiningTechnologies:Number83 Control of welding distortion in thin-plate fabrication Design support exploiting computational simulation Tom Gray, Duncan Camilleri and Norman McPherson AMSTERDAM.BOSTON.CAMBRIDGE.HEIDELBERG.LONDON NEWYORK.OXFORD.PARIS.SANDIEGO SANFRANCISCO.SINGAPORE.SYDNEY.TOKYO WoodheadPublishingisanimprintofElsevier WoodheadPublishingisanimprintofElsevier 80HighStreet,Sawston,Cambridge,CB223HJ,UK 225WymanStreet,Waltham,MA02451,USA LangfordLane,Kidlington,OX51GB,UK Copyright#2014WoodheadPublishingLimited.Allrightsreserved Nopartofthispublicationmaybereproduced,storedinaretrievalsystemortransmitted inanyformorbyanymeanselectronic,mechanical,photocopying,recordingor otherwisewithoutthepriorwrittenpermissionofthepublisher. PermissionsmaybesoughtdirectlyfromElsevier’sScience&TechnologyRights DepartmentinOxford,UK:phone(þ44)(0)1865843830;fax(þ44)(0)1865853333; email:[email protected],youcansubmityourrequestonlineby visitingtheElsevierwebsiteathttp://elsevier.com/locate/permissions, andselecting ObtainingpermissionstouseElseviermaterial. Notice Noresponsibilityisassumedbythepublisherforanyinjuryand/ordamagetopersonsor propertyasamatterofproductsliability,negligenceorotherwise,orfromanyuseor operationofanymethods,products,instructionsorideascontainedinthematerial herein.Becauseofrapidadvancesinthemedicalsciences,inparticular,independent verificationofdiagnosesanddrugdosagesshouldbemade. BritishLibraryCataloguing-in-PublicationData AcataloguerecordforthisbookisavailablefromtheBritishLibrary. LibraryofCongressControlNumber:2013954936 ISBN978-0-85709-047-8(print) ISBN978-0-85709-932-7(online) ForinformationonallWoodheadPublishingpublications visitourwebsiteathttp://store.elsevier.com/ TypesetbyDataStandardsLtd,Frome,Somerset,UK PrintedandboundintheUnitedKingdom Contents Author contact details ix Woodhead Publishing Series in Welding and Other Joining Technologies xi Preface xvii 1 Introduction: development of computational welding mechanics approach to welding distortion 1 1.1 Background: control of welding distortion in fabrication practice 1 1.2 Aims: integrated design approach utilising computational welding mechanics (CWM) 7 1.3 Structure of the book 8 1.4 Conclusion 12 1.5 References 12 2 Fabrication of stiffened thin-plate structures and the problem of welding distortion 14 2.1 Introduction 14 2.2 Welding distortion of stiffened-plate and other fabricated structures 16 2.3 Outline of a typical fabrication process 19 2.4 Raw materials and primary process factors 22 2.5 Management issues relevant to thin-plate distortion 24 2.6 Rectification of thin-plate distortion 37 2.7 Conclusion 38 2.8 References 38 3 Tools to deal with welding distortion: predictive modelling and research on in-process techniques 39 3.1 Introduction 39 3.2 Artificial neural networks (ANNs) 40 3.3 Computational simulation 45 3.4 Current research on reduction of distortion 48 vi Contents 3.5 Conclusion 51 3.6 References 51 4 Understanding welding distortion: thermal fields and thermo-mechanical effects 53 4.1 Introduction 53 4.2 Thermal fields: dependence on welding parameters and material properties 54 4.3 Thermo-mechanical effects 61 4.4 Thermo-mechanical treatment based on longitudinal– transverse uncoupling 65 4.5 Plane strain strip: longitudinal deformations and forces 67 4.6 Transverse welding deformations 69 4.7 Residual stress 71 4.8 Buckling 73 4.9 Conclusion 74 4.10 References 75 5 Computational simulation of welding distortion: an overview 77 5.1 Introduction 77 5.2 Multi-physics 78 5.3 Thermal property non-linearity 81 5.4 Phase change and non-linear thermal dilatation 83 5.5 Mechanical property idealisation 83 5.6 Thermal computation outline 85 5.7 Range of thermo-mechanical approaches available 87 5.8 Reduced solutions and their advantages 91 5.9 Conclusion 99 5.10 References 100 6 Experimental investigation of models of welding distortion: methods, results and comparisons 102 6.1 Introduction 102 6.2 Importance of experimental observations 104 6.3 Welding process application in test work 105 6.4 Thermocouple arrays 105 6.5 Thermography 107 6.6 Deformation measurement 111 6.7 Completion and smoothing of measured deformation profiles 113 6.8 Characterising out-of-plane deformation 118 6.9 Conclusion 123 6.10 References 124 Contents vii 7 Modelling thermal processes in welding 126 7.1 Introduction 126 7.2 Convection and radiation 127 7.3 Heat input modelling 128 7.4 Simulation of weld deposition 132 7.5 Thermal property non-linearity 133 7.6 Three-dimensional transient thermal computation 137 7.7 Transient finite-element model based on two-dimensional cross-section 139 7.8 Thermal computation in stiffener fillet weld geometries 140 7.9 Welding efficiency 145 7.10 Thermal cutting 150 7.11 Conclusion 153 7.12 References 154 8 Computationally efficient methods for modelling welding processes 156 8.1 Introduction 156 8.2 Computationally efficient methods based on algorithms 157 8.3 Hybrid stepwise solution methods 169 8.4 Conclusion 175 8.5 References 176 9 Finite-element thermo-mechanical techniques for welding distortion prediction 177 9.1 Introduction 177 9.2 Formulation of thermo-mechanical finite-element model 178 9.3 Case study: influence of tacking procedures on butt-weld distortion 182 9.4 Case study: fillet-welded stiffened plate 187 9.5 Conclusion 197 9.6 References 197 10 Simulating welding distortion in butt welding of thin plates 199 10.1 Introduction 199 10.2 Plate support and out-of-flatness influences 200 10.3 Effects of tacking 207 10.4 Clamping effects 222 10.5 Residual stress in butt welds 225 10.6 Multiple butt welds 228 10.7 Conclusion 231 10.8 References 232 viii Contents 11 Simulating welding distortion in fillet welding of stiffened plate structures 233 11.1 Introduction 233 11.2 Plates with double-sided continuous fillet-welded single stiffeners: thermal aspects 234 11.3 Plates with double-sided continuous fillet-welded single stiffeners: computationally efficient thermo-mechanical treatment 238 11.4 Multiply-stiffened plates: case study on welding sequence 251 11.5 Conclusion 263 11.6 References 264 12 Exploiting welding distortion models: examples of design and manufacturing strategies to optimise fabrication 265 12.1 Introduction 265 12.2 Optimising multi-stiffener configuration 267 12.3 Optimising the design in terms of weld position 275 12.4 Limiting heat input to avoid buckling 284 12.5 Simulation of transient thermal tensioning: fabrication-related distortion reduction study 288 12.6 Simulated use of low-transformation-temperature filler material to reduce distortion 299 12.7 Simulated use of weld-trailing cryogenic cooling process to reduce distortion 307 12.8 Conclusion 317 12.9 References 318 Index 321 Author contact details (* = main contact) Tom Gray* Norman McPherson University of Strathcylde BAE Systems – Surface Ships UK UK E-mail: [email protected] E-mail: norrie.mcpherson@ baesystems.com Duncan Camilleri University of Malta Malta E-mail: [email protected]. mt