Control of welding distortion in thin plate fabrication: Design support exploiting computational simulation

352 Pages·2014·11.719 MB·English

by  Tom Gray

Control of welding distortion in thin-plate
fabrication
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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
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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: [e-mail] E-mail: norrie.mcpherson@
baesystems.com
Duncan Camilleri
University of Malta
Malta
E-mail: [e-mail].
mt