ICAF 2019 – Structural Integrity in the Age of Additive Manufacturing (eBook)

Preface to ICAF 30th Symposium Proceedings 6
International Committee on Aeronautical Fatigue and Structural Integrity 8
ICAF General Secretary 8
National Delegates 8
Contents 12
Additive Manufacturing 21
Fatigue Characteristic of Linear Friction Welded Ti-6Al-4V Joints 22
Abstract 22
1 Introduction 23
2 Test and Analysis Procedures 25
2.1 Linear Friction Welding 25
2.2 Fatigue Tests 26
2.3 Analysis of Covariance 27
2.4 Residual Stress Measurement 29
3 Results and Consideration 30
3.1 Fatigue Test Results 30
3.2 Analysis of Covariance Results 30
3.3 Residual Stress Measurement Results 31
4 Conclusion 32
Appendix 33
Formula of Analysis of Covariance 33
References 34
Fatigue in Additive Manufactured Aircraft: The Long Way to Make It Fly 35
Abstract 35
1 Introduction 35
2 Additive Manufacturing of Metallic Aircraft Components 38
3 Limits of the AM Process and Future Developments 44
3.1 Techniques of Surface Finishing 45
3.2 Damage Tolerance Approach 45
4 AM Parts with Intrinsically Fail Safe Design 46
5 Conclusions 47
References 48
High Cycle Fatigue and Fatigue Crack Growth Rate in Additive Manufactured Titanium Alloys 50
Abstract 50
1 Introduction 51
2 Methods 52
2.1 Experimental Design 52
2.2 Specimen Design and Testing Method 53
2.2.1 Tensile and Fatigue Testing 53
2.2.2 Fatigue Crack Growth Testing 54
3 Results and Discussion 54
3.1 Effect of Porosity Defects on High Cycle Fatigue 54
3.1.1 Porosity Analysis 54
3.1.2 Tensile and Fatigue Tests 55
3.1.3 Interrupted Fatigue-Tomography Test 55
3.1.4 Stress Intensity Factor Range Applied to Gas Pore Defects 56
3.2 Fatigue Crack Growth Behaviour 57
3.2.1 Crack Orientation 57
3.2.2 Build Methods and Effect on Property Anisotropy 58
4 Conclusions 59
Acknowledgement 59
References 60
Strain Controlled Fatigue Testing of Additive Manufactured Titanium Alloy Ti-6Al-4V 62
Abstract 62
1 Material Conditions 62
2 Specimen Preparation 64
3 Tensile Tests 64
4 Fatigue Tests 65
5 Fatigue Failure Criteria 66
6 Fatigue Characterisation 66
7 Fatigue Test Results and Fatigue Curves 69
8 Conclusions 73
References 74
The Optimization and Design of Complicated-Surface Panel Based on Automate Fiber Placement 75
Abstract 75
1 Introduction 75
2 Theory 76
3 Example 81
4 Effect of Stiffener Parameters on Double-Curvature Stiffened Panel 85
5 Conclusion 88
References 88
Advanced Materials and Innovative Structural Concepts 90
A Modeling Approach for the Fatigue Behavior of Laser Drilled Micro Perforated Structural Panels 91
Abstract 91
1 Introduction into Hybrid Laminar Flow Control 91
2 Manufacturing of Micro Perforated Panels for HLFC 92
3 Link Between Material Properties and Manufacturing Process 93
4 Durability and Wear Resistance 94
5 Fatigue Test Program 1 95
5.1 Test Program 1: Material Direction and Drilling Pattern 95
5.2 Test Program 1: Discussion of Test Results 96
6 Multiple Site Damage 99
7 Fatigue Test Program 2 99
7.1 Test Program 2: Multiple Site Damage 99
7.2 Test Program 2: Discussion of Test Results 100
8 Modeling the Micro Drilling in Fatigue Assessment 103
9 Conclusions 104
References 105
Assessment of Fatigue Behavior of Advanced Aluminum Alloys Under Complex Variable-Amplitude Loading 106
Abstract 106
1 Introduction and Background 106
2 Experimental Method 107
2.1 Variable-Amplitude Spectrum 108
2.2 Finite Element Analysis 109
2.3 Test Control Methodology 110
2.4 Test Setup and Procedure 113
3 Results 114
3.1 Equivalent Stress Determination 114
3.2 Fracture Surface Morphology 115
3.3 Comparison to Full-Scale Panel Results 117
3.4 Comparison of K-Control Method to Load Control Spectrum 119
3.5 Effect of Compressive Landing Load 119
4 Summary 120
References 121
Damage Mechanisms and Mechanical Properties of Directly Bonded CFRTP and Aluminium with Nano-Structured Surface 122
Abstract 122
1 Introduction 122
2 Materials and Experimental Methods 123
3 Results and Discussion 127
4 Conclusion 129
Acknowledgements 130
References 130
Interaction Between High- and Low-Cycle Thermo-Mechanical Fatigue Crack Propagation Around Cooling Hole in a Ni-Based Superalloy 131
Abstract 131
1 Introduction 131
2 Experiments 132
3 Crack Initiation and the Early Growth Around Cooling Holes 135
4 Discussions 137
5 Conclusion 140
Acknowledgements 140
References 140
Ply Curving Termination to Suppress Delamination in Composite Ply Drop-Off 142
Abstract 142
1 Introduction 142
2 Ply Curving Termination 143
3 Finite Element Analysis 144
4 Validation Tests Using Unidirectional Specimens 145
4.1 Tests with 1-Ply Terminated Layer 145
4.2 Tests with Taper Ratio of 1:5 147
5 Validation Tests Using Quasi-isotropic Specimens 148
6 Suppression of Edge Delamination Using PCT 149
7 Conclusions 150
Acknowledgement 150
References 150
Studies on the Fatigue Damage Behavior of Active Jet Engine Chevron 151
Abstract 151
1 Introduction 151
2 Constitutive Model of the SMA Considering Damage 153
3 FE Simulation of the Jet Engine Chevron 158
4 Conclusion 159
Acknowledgement 159
References 159
Airworthiness and Other Considerations 161
An Ultrafast Crack Growth Lifing Model to Support Digital Twin, Virtual Testing, and Probabilistic Damage Tolerance Applications 162
Abstract 162
1 Introduction 163
2 Methodology 164
3 Example Problems 167
4 Conclusion 174
Acknowledgments 174
References 175
Analytical and Numerical Investigation of the Effect of Secondary Bending in Hard-Point Joints 176
Abstract 176
1 Introduction 176
2 Analytical Derivation 179
2.1 The Neutral Line Model 179
2.2 The Neutral Line Model Including Fasteners Flexibilities 182
3 Numerical Investigation 184
4 Fatigue Assessment of Secondary Bending Effect 188
4.1 Fatigue (Crack Nucleation) Lifetime 189
4.2 Crack Growth Lifetime 191
5 Summary and Conclusions 191
References 192
Demonstration of an Airframe Digital Twin Framework Using a CF-188 Full-Scale Component Test 193
Abstract 193
1 Introduction 193
2 ADT Framework Interpretation 194
3 Analysis Tool Development 196
4 Technology Demonstration: CF–188 Ilef Full-Scale Test 198
5 Conclusion 202
References 203
Development of Efficient High-Fidelity Solutions for Virtual Fatigue Testing 204
Abstract 204
1 Introduction 204
2 Virtual Fatigue Testing 205
3 Structural Response Models 207
4 Fatigue Damage (Crack Initiation) Models 209
5 Crack Growth Models 210
6 Residual Strength Models 211
7 Stochastic Response Models 213
8 Verification, Validation & Certification
9 Conclusions 215
Acknowledgments 216
References 216
Effective Durability and Damage Tolerance Training: New Methods for Modern Learners 218
Abstract 218
1 Introduction 218
2 Learning Objectives for Introductory DaDT 220
3 Inductive Learning Approaches 222
4 Active Learning Approaches 225
5 The Value of Real-Life Experiential Learning 227
6 Closing Thoughts 230
Acknowledgments 231
References 231
Fatigue Considerations in the Development and Implementation of Mechanical Joining Processes for Commercial Airplane Structures 232
Abstract 232
1 Structural Build Processes and Fatigue 233
2 Commercial Airplane-Specific Design Considerations 235
3 The Quest for Quality and Production Efficiency 235
4 One-Up Assembly 237
5 Assembly with Pre-drilled Holes 241
6 Conclusion 243
References 244
Rapid Calculation of Safe Acceleration Values for Aircraft Structures Under Flight Test 245
Abstract 245
1 Introduction 245
2 Discussion 246
3 Conclusions 260
Acknowledgements 260
References 260
Reliability Approach Applied on Fatigue Safety Factors for Fleet Monitoring 262
Abstract 262
1 Introduction 262
2 Safety Level Induced by Different Monitoring Systems 263
3 Random Z-Acceleration Spectra 266
4 Non-monitored Aircraft vs Monitored Ones 268
5 Conclusion 272
References 272
Research on the Airworthiness Compliance Strategy of Composite Structure 273
Abstract 273
1 Introduction 273
2 Requirements for Structural Design of Civil Aircraft in the Future 273
3 Analysis on the Evolution of Composites Main Structure Technology 274
4 Design Technology of Automatic Manufacturing of Composites 275
5 Analysis of Airworthiness Conformity of Composite Structures 276
5.1 Material Requirements 276
5.2 Process Requirements 276
5.3 New Form of Structure 277
5.4 Material Allowable Value 277
5.5 Structural Design Value 277
5.6 Damage Tolerance Assessment 277
5.7 Strength Verification 278
6 Test Planning of Composite Main Structures 278
6.1 Development Tests for Design and Manufacturing 278
6.2 Airworthiness Verification Test 280
7 Conclusion 281
References 281
Risks of Initial Assumptions in Fatigue and Damage Tolerance of Small Aircraft Development Programs 282
Abstract 282
1 Introduction 282
2 Risks 283
3 Spectrum Development and Damage Tolerance Evaluation 285
4 Component Design Criteria 286
5 Scatter Factors 286
6 Usage and Mission 287
7 Fatigue Spectrum 289
8 Principal Structural Elements 290
9 Internal Loads 290
10 Material Data 290
11 Stress Intensity Factors 291
12 Crack Growth 292
13 Initial Crack Sizes and Inspections 292
14 Probabilistic Methods 293
15 New Manufacturing Technologies 294
16 Conclusion 294
References 294
Russian Practice to Provide Safe Operation of Airplane Structures with Long-Term Operation 296
Abstract 296
1 Introduction 296
2 Service Life of Aging Aircraft Fleet 297
3 Corrosion 298
4 Widespread Fatigue Damages 301
5 Degradation of Material Properties 304
6 Conclusion 307
References 307
Smarter Testing Through Simulation for Efficient Design and Attainment of Regulatory Compliance 309
Abstract 309
1 Introduction 310
1.1 The Need for Smarter Testing 310
1.2 What is Smarter Testing? 311
2 Damage Tolerance of Composite Structures 312
3 Airframe Crashworthiness 318
4 Seat Certification by Dynamic Simulation 319
5 Looking Ahead 322
6 Summary 323
Acknowledgments 323
References 324
Widespread Fatigue Damage Evaluation for Multiple Elements Based on Probabilistic Approach 325
Abstract 325
1 Introduction 325
2 Background 326
3 Methodology 329
3.1 Typical Fatigue Life, N50 329
3.2 Generating Random Life 330
3.3 Determining WFD Average Behavior 330
3.4 Determining Maintenance Actions 330
3.5 Simplified Method 331
3.6 Analytical Solution 331
4 Case Study 331
5 Discussion and Conclusion 334
References 335
Fatigue Crack Growth and Life Prediction Methods 336
A Framework to Implement Probabilistic Fatigue Design of Safe-Life Components 337
Abstract 337
1 Introduction 337
2 Justification for Developing a Probabilistic Framework 338
3 Required Methods and Framework for a Probabilistic Approach 340
3.1 Statistical Characterisation of Fatigue Design Data 340
3.2 Probabilistic Methods 340
3.3 Surrogate Modelling 341
3.4 Sensitivity Analysis 343
3.5 Framework for Probabilistic Approach to Safe-Life Fatigue Design 343
4 Previous Probabilistic Approaches to Safe-Life Fatigue Design 344
5 Challenges of Implementing Probabilistic Approaches 345
5.1 Computational Expense 345
5.2 Selection of Methods 345
5.3 Verification and Validation 346
5.4 Availability of Data 346
5.5 Mindset Change and Design Criteria 347
5.6 Technical Knowledge and Resources Required 347
6 Conclusion 349
Acknowledgements 350
REFERENCES 350
A Multiaxial Fatigue Damage Model for Isotropic Materials 352
Abstract 352
1 Introduction 352
2 Damage Model Formulation 353
3 Model Validation 361
4 Conclusions 363
Acknowledgements 363
References 364
A Specimen to Evaluate Susceptibility of Aluminium Alloys to L-S Crack Deviation 365
Abstract 365
1 Introduction 365
2 Materials and Methods 366
3 Results 370
4 Discussion 372
5 Conclusion 374
Acknowledgements 375
References 375
A Numerical Approach to the Disbonding Mechanism of Adhesive Joints 376
Abstract 376
1 Introduction 376
2 Experimental Method 378
3 Numerical Model 379
4 Results and Discussion 382
4.1 Mode I 382
4.2 Mode II 384
5 Conclusions 386
References 386
An Engineering Calculation Method of Probability Distribution of Crack Initiation Life for Widespread Fatigue Damage 388
Abstract 388
1 Analytical Model of Crack Initiation Life Probability Distribution 389
1.1 Probability Distribution of Crack Initiation Life of Single Detail 389
1.2 Probability Distribution of Crack Initiation Life of Multiple Details 389
2 Crack Initiation Tests with Single Hole and Multiple Holes Notched Specimens 391
2.1 Crack Initiation Test with Single Hole Notched Specimen 391
2.1.1 Test Program 391
2.1.2 Test Result 392
2.2 Crack Initiation Test with Multiple Holes Notched Specimen 393
2.2.1 Test Program 393
2.2.2 Test Result 394
3 Data Analysis 397
4 Discussion and Conclusion 398
References 398
Assessment of Aircraft Structural Service Life Using Generalized Correction Methodology 400
Abstract 400
1 Introduction 400
2 Generalized Correction Methodology 401
3 Selection of DADT Models 404
4 Sensitivity Analyses of Model Parameters 405
5 Case Study 407
6 Conclusions 413
Acknowledgement 413
References 414
Examination of the KAWAI CLD Method for Fatigue Life Prediction of Composites 415
Abstract 415
1 Introduction 415
2 Kawai CFL Model for Fatigue Life Prediction 416
3 Test Description 417
4 Analysis of Test Results 419
5 Modified KAWAI CLD 423
6 Summary and Conclusions 424
References 425
Fatigue Crack Growth Prediction and Verification of Aircraft Fuselage Panels with Multiple Site Damage 426
Abstract 426
1 Introduction 426
2 Description of the Model 427
3 Material and Specimens 431
4 Experimental Technique 432
5 Crack Growth Analysis Procedure 433
6 Results and Discussion 434
7 Conclusion 438
References 438
Fatigue Life Prediction of CFRP Laminate Under Quasi-Random Loading 439
Abstract 439
1 Introduction 439
2 Results of Fatigue Tests 440
3 Fatigue Life Prediction Methods 441
4 Prediction Results 444
5 Discussion 446
6 Conclusion 447
References 447
Fatigue Life Simulation and Experiment of 2024 Aluminum Joints with Multi-Fasteners Interference-Fit 448
Abstract 448
1 Introduction 448
2 Experimental Materials and Methods 449
3 Simulation Analysis of Installation 451
4 Fatigue Life 453
4.1 Fatige Life Simulation Results 455
5 Conclusion 458
Acknowledgements 458
References 458
Influence of Heat Treatment on Near-Threshold Fatigue Crack Growth Behavior of High Strength Aluminum Alloy 7010 460
Abstract 460
1 Introduction 461
2 Materials and Methodology 461
2.1 Alloy Heat Treatment 461
2.2 Alloy Microstructure 462
2.3 Fatigue Crack Growth Tests 462
3 Results and Discussion 463
3.1 Microstructural Details 463
3.2 Fatigue Crack Growth Behavior 464
4 Conclusions 467
Acknowledgements 467
References 467
Multiaxial Fatigue Behavior of 30HGSA Steel Under Cyclic Tension-Compression and Reversed Torsion 468
Abstract 468
1 Introduction 468
2 Specimen and Test Set-Up 469
2.1 Monotonic Tensile Curve 470
2.2 Fatigue Tests for Complex Tension-Compression and Reversed Torsion 471
3 High-Cycle Fatigue Analysis Under Combined Stresses 472
3.1 Gough–Pollard (GP) Model 472
3.2 D?bski–Golos–D?bski Limit Curves of Complex Stress State Model (DGD-LC) 473
3.3 Comparison with the Experimental Data for 30HGSA Steel 474
4 Conclusions 475
References 476
Novel Methods for Measuring the Mode I and Mixed Modes I/II Interlaminar Fracture Toughnesses of Composite 477
Abstract 477
1 Introduction 477
2 Review of the ASTM Standards for Measuring the Mode I and Mixed Modes I/II Interlaminar Fracture Toughness 478
2.1 Overview of the ASTM Methods for Mode I Interlaminar Fracture Toughness 478
2.2 Brief Overview of the Energy Release Rate Solution 480
3 Compliance and Strain Solutions to the DCB and MMB 481
3.1 Compliance Solution to the DCB 481
3.2 Compliance Solution to the MMB 482
3.3 Strain Distribution Solution to the MMB 483
4 Novel Methods for Measuring the Mode I and Mixed Modes I/II Interlaminar Fracture Toughness 483
4.1 Double Compliances Method for DCB 483
4.2 A Combined Strain and Compliance Method to Determine E11 and ? 484
5 DCB Test and Fracture Toughness Determination 485
5.1 DCB Test at Low Temperature Environment 485
5.2 Fracture Toughness of Unidirectional Composite at Low Temperature 487
6 MMB Test and Fracture Toughness Determination 487
6.1 MMB Test 487
6.2 Test Results and Determinations of the Fracture Toughness 489
7 Conclusions 491
References 491
Numerical Investigations on the Three-Dimensional I/II Mixed-Mode Elasto-Plastic Fracture for Through-Thickness Cracked Bodies 493
Abstract 493
1 Introduction 493
2 Finite Element Simulation 494
2.1 Finite Element Models 494
2.2 Verification of Finite Element Models 495
3 The Analysis of a Mixed-Mode Elasto-Plastic 3-D Stress Field 496
4 The Thickness Effect of Load Carrying Under Mixed-Mode I/II Loading Conditions 500
5 Conclusions 502
References 503
Probabilistic Reliability Assessment of a Component in the Presence of Internal Defects 504
Abstract 504
1 Introduction 504
2 Experimental Procedures 505
3 Fatigue Properties 506
4 Modelling Strategy 508
4.1 Fracture Mechanics Framework 509
4.2 Short Crack Models 511
4.2.1 Kitagawa-Takahashi Diagram (KT Diagram) 511
4.2.2 Cyclic R-Curve 512
5 Application of the Model 514
5.1 Prediction of Fatigue Scatter 514
5.2 P-S-N Curves 516
6 Conclusions 517
References 517
Stress-Intensity Factor Solutions for Tapered Lugs with Oblique Pin Loads 519
Abstract 519
1 Introduction 519
2 Overview 521
3 Analysis Details 522
4 Sensitivity 525
5 Formulation 526
6 Solution Verification and Validation 528
7 Summary 531
References 532
Summary of Recent Round Robin Life Prediction Efforts for Crack Shape and Residual Stress Effects 534
Abstract 534
1 Introduction 534
2 Test Specimen Geometry 535
3 AFGROW Workshop Summary 535
4 ERSI Workshop Summary 538
5 Conclusion 542
References 542
The Influence of Low and High-Cycle Fatigue on Dislocations Density and Residual Stresses in Inconel 718 544
Abstract 544
1 Material Examined and Measurement Methodology 545
2 Conclusions 553
References 553
Effect of Crack Length and Reference Stress on Variable Amplitude Fatigue Crack Growth Rate 555
Abstract 555
1 Introduction 555
2 Experimental Set-up 558
3 Results 559
4 Discussion 564
5 Conclusions 565
References 565
Weibull or Log-Normal Distribution to Characterize Fatigue Life Scatter – Which Is More Suitable? 567
Abstract 567
1 Introduction 567
2 Supersmith Software, a Convenient Tool for Evaluating Statistical Distributions 568
3 Analysis of the Test Results 568
4 An Alternate Method to Establish Whether the Weibull or the Log-Normal Distribution Is Better Suitaed to Describe Fatigue Life Scatter 571
5 Results of Applying the Method Described Above to the 86-Specimen Database 571
5.1 Median Rank of the Test Points 573
6 Placing the Weibull and Log-Normal Data on a Single Log-Log Plot 576
7 Summary and Conclusions 577
References 577
Fatigue Life Enhancement Methods and Repair Solutions 578
Bonded Repairs of Composite Panels Representative of Wing Structure 579
Abstract 579
1 Introduction 579
2 Experimental Procedures 581
2.1 Test Fixture 581
2.2 Panel Description 581
2.3 Test Phases 582
2.4 Applied Loads 583
2.5 Inspection and Monitoring Methods 584
3 Analysis 585
3.1 Finite Element Analysis 585
3.2 BRSL Semi-analytical Method Development and Verification 586
4 Results and Discussion 587
4.1 Phase 1, Baseline Study 587
4.2 Phase 2, BRSL Study 589
4.3 Test and Analysis Correlation 591
5 Summary 593
References 594
Comparison of Rivet Hole Expansion for Protruding Rivets Universal and with Compensator
Abstract 595
1 Introduction 595
2 FE Models 596
3 Validation 598
4 Results 599
5 Conclusions 601
Acknowledgements 601
References 602
Effect of Alternative Paint Stripping Processes on the Fatigue Performance of Aluminium Alloys - Atmospheric Plasma De-painting 603
Abstract 603
1 Introduction 603
2 Materials and Experimental Approach 604
2.1 Dog-Bone Fatigue Testing 605
2.2 Large Panel Crack Growth 606
3 Results 608
3.1 Dog-Bone Fatigue Testing 608
3.2 Large Panel Crack Growth 610
4 Concluding Remarks 612
Acknowledgements 612
References 613
Effect of Strengthened Hole on the Fatigue Life of 2024-T3 Aluminum Alloy 614
Abstract 614
1 Introduction 614
2 Experimental Materials and Methods 615
2.1 Material 615
2.2 Cold Expansion 615
2.3 Fatigue Test 615
2.4 Residual Stress Test and Fracture Check 615
3 Results and Discussion 616
3.1 Fatigue Life Analysis 616
3.2 Residual Stress Analysis 616
3.3 Fracture Analysis 618
4 Conclusions 618
References 619
Fatigue Crack Growth in Pin Loaded Cold-Worked Holes 620
Abstract 620
1 Introduction 620
2 Experimental Activity 621
3 Experimental Results 622
4 Numerical Activity 626
4.1 Crack Fronts Without Pre-defined Shapes 626
4.2 Plasticity-Induced Crack Closure 628
5 Conclusions 630
References 630
Fatigue Crack Propagation Influenced by Laser Shock Peening Introduced Residual Stress Fields in Aluminium Specimens 631
Abstract 631
1 Introduction 631
2 Experimental Techniques and Set-up 632
3 Numerical Modelling 636
4 Results and Discussion 638
5 Conclusion 643
References 644
Influence of Bonded Crack Retarders on Damage Tolerance Performance of Fuselage Panel 646
Abstract 646
1 Introduction 646
2 Specimens 647
3 Test Setup 648
4 Test Results 650
5 FE Modelling and Crack Growth Prediction 651
6 Residual Strength Prediction 654
7 Conclusion 655
References 655
Is the Civil Aerospace Industry Ready to Implement Laser Shock Peening into Maintenance Environment? Questions to Be Answered and Minimum Requirements from Aircraft Manufacturer’s Perspective 657
Abstract 657
1 Introduction 658
2 Constrains and Requirements For LSP at MRO 659
3 Low Energy LSP System (i.e. Portable LSP) Performance 664
4 Experimental Approach 667
5 Experimental Results and Discussion 668
6 Conclusions 670
References 670
Fatigue Life Prediction at Cold Expanded Fastener Holes with ForceMate Bushings 672
Abstract 672
1 Introduction 672
2 Residual Stresses 674
3 Fatigue Life 677
4 Crack Growth 679
5 Concluding Remarks 685
References 686
Why Should We Encourage Usage of Interference-Fit Fasteners at Airframe Structural Joints? 688
Abstract 688
1 Introduction 688
2 The Experimental Investigation 690
3 The Experimental Investigation 694
4 Numerical Analyses and Evaluations 700
5 Conclusion 704
References 704
Full Scale Fatigue Testing of Aircraft and Aircraft Components 706
Analysis Prediction and Correlation of Fiber Metal Laminate Crack Growth in Semi-Wing Full-Scale Test 707
Abstract 707
1 Introduction 707
2 Full-Scale Test 709
3 Methodology 711
4 Results and Discussion 714
5 Conclusion 718
References 718
Bombardier Global 7500 Fatigue Test Cycle Rate Commissioning to ¼ Life 720
Abstract 720
1 Introduction 721
1.1 Background 721
1.2 Schedule 721
1.3 Global 7500 DADTT 722
2 Rig Design for Test Acceleration 722
3 Dedicated Test Platform 724
4 Data Informed Hydraulic/Pneumatic Design Selections 725
5 Initial Transition Time Estimation and Optimization 731
6 Results 732
Reference 734
Changing the Philosophy of Full-Scale-Fatigue-Tests Derived from 50 Years of IABG Experience Towards a Virtual Environment 735
Abstract 735
1 Introduction 735
2 Evolution of Full-Scale-Fatigue-Tests 736
3 Evolution of Virtual Qualification Capabilities 737
4 Exploiting the Potential of the FSFT 738
4.1 Hardware-in-the-Loop Testing 738
4.2 Model Validation 738
4.3 Data Science and Machine Learning 740
4.4 Structural Health Monitoring and Predictive Maintenance 741
4.5 Digital Twin 742
4.6 Future Benefits from FSFT 742
5 How to Develop the FSFT 743
5.1 Introducing Agility to FSFT 743
6 Certification – No Challenges? 745
7 Conclusion 746
References 747
Combined Static and Fatigue Tests of the Full-Scale Structure of a Transport Aircraft 748
Abstract 748
1 Introduction 748
2 Object of Testing 748
3 Test Procedure 749
4 The Complex for Testing 750
5 Researching the Stresses of the Wing Box Structure 752
6 Tests of Full Scale Panels for Stability 755
7 Conclusion 758
Conception of Modular Test Stand for Fatigue Testing of Aeronautical Structures 759
Abstract 759
1 Introduction 759
2 Conception of the Modular Test Stand 760
3 Design 762
4 Installation and Verification 764
5 Conclusions 771
Acknowledgements 772
References 772
Full Scale Fatigue Testing for Mitsubishi Regional Jet 774
Abstract 774
1 Introduction 774
2 Evaluation Approach 775
3 Full Scale Fatigue Test Overview 775
4 Test Loading 775
5 Test Spectrum Verification 777
6 Prediction Analysis for WFD 777
7 Thermal Stress at Hybrid Joint 778
8 Full Scale Level Damage Tolerance Tests 779
9 Conclusion 781
References 782
Full-Scale Fatigue and Residual Strength Tests of the Composite Wing Box of a Passenger Aircraft 783
Abstract 783
1 Introduction 783
2 Object of Testing 784
3 Test Procedure 784
4 Test Set Up 785
5 Researching the Deformations of the Wing Box Structure 786
6 Inspection of the Wing Box Before Testing 787
7 Impact Damaging the Structure 788
8 Tests of Wing Box ?1 790
9 Tests of the Wing Box ?2 793
10 Analysis of Test Results 796
11 Conclusion 798
References 799
Full-Scale Fatigue Testing from a Structural Analysis Perspective 800
Abstract 800
1 Introduction 800
2 Test Preparation and Execution 801
3 Loading Program Definition 804
4 Test Damage Management 805
5 Smarter Testing & Simulation
6 Conclusion 811
References 812
Hawk Mk 51/51A/66 Tailplane Full-Scale Fatigue Tests 813
Abstract 813
1 Introduction 813
2 Methods 815
3 Results 824
4 Conclusions 826
References 826
Progress on the Pathway to a Virtual Fatigue Test 828
Abstract 828
1 Background 828
2 The ASSIST Program 829
3 A Pathway to a Virtual Fatigue Test 830
4 The ASSIST Framework and Current Progress 831
5 Airframe Challenge 1: Fighter Wing Root Shear-Tie Post 833
6 Driving Innovative Aircraft Sustainment 839
7 Summary 840
Acknowledgements 841
References 841
Testing Approach for Over Wing Doors Using Curved Fuselage Panel Testing Technology 843
Abstract 843
1 Introduction 843
2 Test Scenario Selection 844
3 Development of Rig Adaptation 845
4 Determination of Test Loads 846
5 Results Comparing Calculation and Test 848
6 Summary 849
References 849
Very High-Cycle Fatigue Characteristics of Cross-Ply CFRP Laminates in Transverse Crack Initiation 850
Abstract 850
1 Introduction 851
2 Experiments 851
3 Evaluation Model 853
4 Results and Discussions 854
5 Conclusions 857
References 857
Application of Optical Fiber-Based Strain Sensing for the Full-Scale Static and Fatigue Tests of Aircraft Structure 859
Abstract 859
1 Introduction 859
2 System Application 860
3 Test Results 860
4 The Digital Twin 862
5 Summary 863
References 864
In-Service Experience, Life Extension and Management of Aging Fleets 865
Analysis of Adhesive Disbond Occurrences in Rotor Blades of Mi-2 Helicopters 866
Abstract 866
1 Introduction 866
2 Disbond Detection and Characteristics 868
3 Conclusion 874
References 875
Approach to Evaluation of Delamination on the MiG-29’s Vertical Stabilizers Composite Skin 876
Abstract 876
1 Physical Modeling 876
1.1 Research Object 876
1.2 Damage and Manufacturing Defects 877
2 Verification of the Damage Model on the Example of CAI Test 879
2.1 CAI Substantiation 879
2.2 CAI Research Object 879
2.3 FEM Modeling 881
2.4 Analysis Results 882
3 Conclusion 884
References 884
Evaluation of a PC-9/A Wing Main Spar with Misdrills Using Enhanced Teardown at Resonance 885
Abstract 885
1 Introduction 885
2 Background 886
3 Key Concept – Enhanced Teardowns 887
4 Experimental Design and Apparatus 888
5 Wing Loading and Marker Bands 891
6 Damage Tolerance Analysis Predictions 892
7 Experimental Phase 893
8 Teardown and Fractography 894
9 Discussion 897
10 Conclusions 898
Acknowledgements 898
References 898
Holistic Approach for Determining a Helicopter’s Airframe Interval for Depot Induction 900
Abstract 900
1 Purpose 901
2 Background 901
3 Methodology 902
4 Analysis for Determining the PDM Induction Interval 907
5 Results 914
6 Conclusion 914
Structural Health and Structural Loads Monitoring 915
A Guidance to Derive Statistical Data for Asymmetrical Maneuvers on Transport Operation 916
Abstract 916
1 Introduction 916
2 Prototypes Flight Tests Data 917
3 Reference Flight Parameters 918
4 Data Acquisition Rate 920
5 Criteria for Flight Phase Segmentation 921
6 Counting Method: Procedures and Criteria 921
7 Statistical Datasets 922
8 Conclusions 928
9 Guidance to Derive Statistical Dataset 929
10 Next Steps 929
Acknowledgments 929
References 930
A Machine Learning Approach to Load Tracking and Usage Monitoring for Legacy Fleets 931
Abstract 931
1 Introduction 932
2 Flight Data 932
2.1 CH-146 Griffon Data 932
2.2 S-70A-9 Black Hawk Data 934
3 Methodology for Load Signal Estimation and Fatigue Life Tracking 935
3.1 Validation Error Measures and Metrics 936
3.2 Prediction Methods 936
3.3 Load Estimation Models 937
4 Validation Results 937
5 Application of Load Signal Estimates 942
6 Conclusion 944
Acknowledgments 945
References 945
Structural Integrity Control Technology Based on Structural Damage Monitoring 947
Abstract 947
1 Introduction 947
2 Measurement and Control of Aircraft Structural Integrity 949
2.1 Measurement of Aircraft Structural Integrity 949
2.1.1 Aircraft Structural Integrity Degree 949
2.1.2 Aircraft Structural Durability Degree 951
2.1.3 Aircraft Availability Degree 951
2.1.4 Aircraft Structural Safety Degree 952
2.1.5 Aircraft Structural Livability Degree 952
2.2 Control of Aircraft Structural Integrity 952
2.2.1 Basic Concept of Aircraft Structural Integrity Control 952
2.2.2 Basic Connotation of Aircraft Structural Integrity Control 953
3 Structural Damage Monitoring Technology 955
3.1 Composition of Aircraft Structural Damage Monitoring System 955
3.1.1 Signal Sources and Drivers 955
3.1.2 Sensor Network 955
3.1.3 Signal Acquisition and Processing Module 956
3.1.4 Damage Identification System 956
3.1.5 Status Assessment Center 956
3.2 Method for Determining Important Positions 956
3.3 Sensor Selection 957
3.4 Signal Processing and Analysis 958
3.4.1 Signal Processing 958
3.4.2 Signal Analysis 958
4 Structural Integrity Control Based on Structural Damage Monitoring 958
4.1 Implementation Steps 958
4.2 Characteristic Advantages 959
5 Military Aircraft Structural Battle Integrity 960
5.1 Structural Battle Integrity 960
5.2 Structural Recoverability 961
5.3 Measurement and Control of Structural Battle Integrity 962
6 Summary 963
Acknowledgements 963
References 964
Application of RLC Filters and Analog Circuits for Increasing Information Bandwidth of Channels of Data Acquisition Units 965
Abstract 965
1 Introduction 965
2 The Methodology of the Approach 966
3 Implementation of the Approach 967
4 The Results of Simulations and Test Measurements 969
5 The Results of Laboratory Tests 971
6 Summary 974
References 974
Effect of Plate Thickness and Paint on Lightning Strike Damage of Aluminum Alloy Sheet 975
Abstract 975
1 Introduction 975
2 Experiment Procedure 976
2.1 Specimen 976
2.2 Simulated Lightning Test 977
2.3 Lightning Damage Measurement 978
3 Test Result 979
3.1 Action Integral 979
3.2 Damage Measurement 980
3.3 High Speed Camera Image 982
4 Conclusion 983
Acknowledgment 984
References 984
Evaluating the Influence of SHM on Damage Tolerant Aircraft Structures Considering Fatigue 985
Abstract 985
1 Introduction 985
2 Theoretical Background 986
3 Impact of Shm on Damage Tolerant Aircraft Structures Prone to Fatigue 993
4 Use Case Evaluation of Defined Methodology on Airbus A320-200 Type Aircraft 996
5 Conclusion 1001
Acknowledgements 1001
References 1001
Fatigue Crack Growth Approach for Fleet Monitoring 1003
Abstract 1003
1 Introduction 1003
2 Tests Setup 1004
3 Initiation and Propagation Models 1005
3.1 Initiation Model 1005
3.2 Propagation Model #1: Paris Law 1005
3.3 Propagation Model #2: Elber Law 1006
3.4 Propagation Model #3: PREFASS 1006
3.5 Propagation Model #4: ONERA 1008
3.6 Propagation Model #5: NASGRO 1009
4 Results Computation 1009
4.1 Initiation Phase – Fatigue Index (FI) Computation 1009
4.2 Propagation Phase – Propagation Index (IP) Computation 1010
4.3 Stress Intensity Factor (SIF) Computation 1010
4.4 Crack Length and Loads Definition 1011
5 Results 1011
5.1 Initiation and Propagation Tests Results for CT Coupons 1012
5.2 Numerical Investigations on CT Coupons Crack Propagation - PI 1013
5.3 Numerical Investigations on Complex Coupons - PI 1015
6 Conclusion 1017
References 1018
Flight Testing of an Ultrasonic Based SHM System 1019
Abstract 1019
1 Introduction 1020
2 Overview of an Ultrasonic Based SHM System 1020
3 Objective of Flight Testing 1021
4 Procedures of Flight Testing 1022
5 Results and Discussions 1025
6 Conclusions of Flight Testing 1029
Acknowledgement 1029
References 1030
Lightning Strike Damage of CF/Epoxy Composite Laminates with Conductive Polymer Layers 1031
Abstract 1031
1 Introduction 1031
2 Experimental 1033
3 Results and Discussions 1035
4 Conclusion 1038
Acknowledgement 1039
References 1039
Machine Learning Application on Aircraft Fatigue Stress Predictions 1040
Abstract 1040
1 Introduction 1041
2 Advanced Data Analyses with Machine Learning Applications 1043
3 Machine Learning Applications for Stress Relevant Predictions 1044
3.1 Example Applications Based on ‘Supervised Learning’ Methods 1045
3.1.1 Machine Learning Capabilities for Stress Sizing and Design Activities 1045
3.1.2 Machine Learning Capabilities for Predictive Aircraft Maintenance Solutions 1048
3.2 Example Applications Based on ‘Unsupervised’ Learning Methods 1048
3.3 Controlling Possible Uncertainties in Machine Learning Predictions for Engineering Applications 1049
4 Summary and Outlook 1050
References 1051
Modernizing the A-10 Loading Spectrum Development Process 1052
Abstract 1052
1 Introduction 1052
2 A-10 Usage and Spectrum History 1053
3 Development of New Processing Tools 1054
4 Transition from Legacy to New Processing Tools 1057
5 Data from the New System and Tools 1058
6 Transition of Processing to the Air Force 1061
7 Conclusion 1062
8 Distribution Statement 1062
Nondestructive Evaluation for Damage Tolerance Life Management of Composite Structures 1063
Abstract 1063
1 Introduction 1064
2 Slow Damage Growth Modeling 1065
3 NDE/I Damage Characterization 1068
4 Summary 1072
References 1072
Perspective of Structural Health Monitoring for Military Aviation in Poland 1074
Abstract 1074
1 Introduction 1075
2 PZL 130 Orlik TC II Aircraft 1076
3 Composite Structures on the Example Remotely Piloted Aerial System HORNET 1081
4 Conclusion 1089
References 1090
Real-Time Stress Concentration Monitoring of Aircraft Structure During Flights Using Optical Fiber Distributed Sensor with High Spatial Resolution 1091
Abstract 1091
1 Introduction 1092
2 Optical Fiber Distributed Sensing 1092
3 Flight Test 1093
4 Results and Discussions 1095
5 Conclusions 1099
References 1099
Research on the Scatter of Structural Load-Time History in a Fleet 1100
Abstract 1100
1 Introduction 1100
2 Procedures of Scatter Analysis 1101
3 Case Study 1104
4 Conclusion 1108
References 1108
Study of Composite Impact Dent Visual Detectability and Damage Relaxation Phenomena 1110
Abstract 1110
1 Introduction 1110
2 Methodology 1112
3 Results and Discussion 1115
4 Conclusion 1119
References 1119
Study of Load Spectrum Occurring in the Course of Photogrammetric Missions of the UAV 1121
Abstract 1121
1 Introduction 1121
2 Classic and Modern Approaches to Fatigue Life Calculations 1123
3 Characterization of Critical Element of PW-Zoom Structure 1126
4 Software Supporting Load Spectra Derivation 1127
5 Example of Data Processing 1128
6 Comparison of Three Photogrammetry Missions Performed in Different Wind Conditions 1133
7 Conclusions 1135
Acknowledgments 1135
References 1135
Substitute Models for Structural Components Loads Estimation Based on Flight Parameters and Statistical Inference Methods 1137
Abstract 1137
1 Introduction 1138
2 Determining Loads of Vertical Stabilizer of a Twin Tailed Aircraft 1142
3 Conclusion 1146
References 1146
Technical Justification for an Ultrasonic Inspection Procedure Applied to a Helicopter Component 1147
Abstract 1147
1 Introduction 1147
2 Outline of Technical Justification 1148
3 Input Information 1148
4 Analysis of Influential and Essential Parameters 1149
4.1 Input Group Parameters 1150
4.2 Procedure Group Parameters 1150
4.3 Equipment Groups Parameters 1150
5 Physical Reasoning (Qualitative Assessment) 1151
6 Prediction by Modelling 1152
7 Experimental Evidence 1156
8 Parametric Studies 1157
9 Summary of Findings and Conclusions 1157
Acknowledgements 1158
References 1158
The Research of Aircraft Structure Health Monitoring System Based on Big Data Analysis 1159
Abstract 1159
1 Introduction 1159
2 SHMS in China 1160
3 SHMS Based on Big Data Analysis 1160
3.1 Effect of SHMS on Reliability Life of Aircraft Fleet 1166
4 Conclusion 1167
References 1168
Author Index 1169