**Simulation in Textile Technology: Theory and Applications**

**Contents **

Contributor contact details ix

Woodhead Publishing Series in Textiles xi

Acknowledgements xxi

Preface xxiii

1 Introduction to modelling and simulation in textile technology 1

D. Veit, RWTH Aachen University, Germany

1.1 Introduction to simulation 1

1.2 Simulation with and without computers 2

1.3 Modelling: white, black and grey box models 3

1.4 Expert systems and other knowledge-based models 4

1.5 Applications of expert systems to textile technology 6

1.6 References and further reading 7

2 Neural networks and their application to textile technology 9

D. Veit, RWTH Aachen University, Germany

2.1 Introduction: biological background 9

2.2 Models of artificial neural networks 13

2.3 The backpropagation algorithm 20

2.4 Counterpropagation 38

2.5 Other types of neural networks 47

2.6 Applications of neural networks to textile technology 47

2.7 Practical advice in applying neural networks 63

2.8 Summary 67

2.9 Web references for software tools 68

2.10 References and further reading 69

3 Evolutionary methods and their application to textile technology 72

D. Veit, RWTH Aachen University, Germany

3.1 Introduction 72

3.2 Biological background 73

3.3 Mathematical models of evolution strategy 79

3.4 Genetic algorithms 91

3.5 Comparison of evolutionary algorithms and iteration processes 92

3.6 Applications of evolutionary algorithms to textile technology 93

3.7 Practical advice in applying evolutionary methods 108

3.8 Web references for software tools 109

3.9 References 110

4 Fuzzy logic and its application to textile technology 112

D. Veit, RWTH Aachen University, Germany

4.1 Introduction 112

4.2 Imprecise mathematics 115

4.3 Set operations 117

4.4 Fuzzy logic versus probabilistic logic 120

4.5 Ultra-fuzzy logic 120

4.6 Fuzzy control 120

4.7 Fuzzy control with four input and one output variable 127

4.8 Applications of fuzzy logic in textile technology 132

4.9 Practical advice in applying fuzzy logic 138

4.10 Web references for software tools 138

4.11 References 139

5 Computational fluid dynamics (CFD) and its application to textile technology 142

P. Jungbecker and D. Veit, RWTH Aachen University, Germany

5.1 Introduction 142

5.2 From reality to simulation 143

5.3 Simulation of currents with fibres, yarns and textiles 151

5.4 Validation methods 153

5.5 Economic aspects 156

5.6 Applications of computational fluid dynamics to textile technology 158

5.7 Practical advice in applying computational fluid dynamics 167

5.8 Summary 168

5.9 Web references for software tools 168

5.10 References 169

6 The finite element method (FEM) and its application to textile technology 172

Y. K. Kyosev, Hochschule Niederrhein – University of Applied

Sciences, Germany

6.1 Introduction 172

6.2 Modelling of mechanical systems 174

6.3 Elements of elastic models 193

6.4 Error estimation and refinement 205

6.5 Nonlinear problems 207

6.6 FEM software 213

6.7 Future trends 215

6.8 Sources of further information 217

6.9 References 218

7 Simulation of fibrous structures and yarns 222

B. Neckář and M. Vyšanská, Technical University of Liberec,

Czech Republic

7.1 Introduction 222

7.2 Fibres and yarns: definitions and factors affecting quality 223

7.3 Fibrous assemblies: volume, density and mass 225

7.4 Yarn parameters: fineness, density, diameter and twist 228

7.5 Modelling of internal yarn geometry: helical yarn model 234

7.6 Stress–strain relations 242

7.7 The relationship between yarn count, twist, packing density and diameter 245

7.8 A simple mechanical model of yarn properties 249

7.9 Mechanics of parallel fibre bundles 258

7.10 Examples of models of fibrous assemblies and yarns 263

7.11 Acknowledgement 264

7.12 References 264

8 Simulation of wound packages, woven, braided and knitted structures 266

Y. K. Kyosev, Hochschule Niederrhein – University of Applied

Sciences, Germany

8.1 Introduction: objectives of simulating yarn-based

structures 266

8.2 Principles of geometrical and mechanical modelling 268

8.3 Simulation of wound packages 271

8.4 Simulation of woven structures 279

8.5 Simulation of braided structures 290

8.6 Simulation of knitted structures 297

8.7 Future trends 304

8.8 Sources of further information 304

8.9 References 306

9 Simulation of textile machinery 310

D. Veit, RWTH Aachen University, Germany

9.1 Introduction: simulation methods to optimize machine settings and product quality 310

9.2 Simulating yarn production and processing: ring/rotor spinning and false-twist texturing 312

9.3 Simulating fabric production: weft insertion and warp tension 324

9.4 Simulating finishing techniques: rolling and dyeing 340

9.5 Simulating plant layout and production planning: finishing operations 341

9.6 Practical advice in simulating textile machinery 346

9.7 References and further reading 346

Index 349