Page 12 - Wind Energy Handbook

xii CONTENTS

7.1.2 Aerodynamic design 378
7.1.3 Practical modifications to optimum design 379
7.1.4 Form of blade structure 379
7.1.5 Blade materials and properties 380
7.1.6 Properties of glass/polyester and glass/epoxy composites 384
7.1.7 Properties of wood laminates 389
7.1.8 Governing load cases 392
7.1.9 Blade resonance 407
7.1.10 Design against buckling 413
7.1.11 Blade root fixings 417
7.2 Pitch Bearings 419
7.3 Rotor Hub 421
7.4 Gearbox 424
7.4.1 Introduction 424
7.4.2 Variable loads during operation 425
7.4.3 Drive-train dynamics 427
7.4.4 Braking loads 427
7.4.5 Effect of variable loading on fatigue design of gear teeth 428
7.4.6 Effect of variable loading on fatigue design of bearings and shafts 432
7.4.7 Gear arrangements 433
7.4.8 Gearbox noise 435
7.4.9 Integrated gearboxes 437
7.4.10 Lubrication and cooling 437
7.4.11 Gearbox efficiency 438
7.5 Generator 438
7.5.1 Induction generators 438
7.5.2 Variable-speed generators 441
7.6 Mechanical Brake 442
7.6.1 Brake duty 442
7.6.2 Factors govnering brake design 443
7.6.3 Calculation of brake disc temperature rise 445
7.6.4 High-speed shaft brake design 447
7.6.5 Two level braking 450
7.6.6 Low-speed shaft brake design 450
7.7 Nacelle Bedplate 450
7.8 Yaw Drive 451
7.9 Tower 453
7.9.1 Introduction 453
7.9.2 Constraints on first-mode natural frequency 454
7.9.3 Steel tubular towers 455
7.9.4 Steel lattice towers 464
7.10 Foundations 464
7.10.1 Slab foundations 465
7.10.2 Multi-pile foundations 466
7.10.3 Concrete mono-pile foundations 467
7.10.4 Foundations for steel lattice towers 468
References 468