 | Preisighe Viana, Marcus Vinicius. Multipoint model for flexible aircraft loads monitoring in real time: Diss. ... Dr.-Ing. / Deutsches Zentrum für Luft- und Raumfahrt, Institut für Flugsystemtechnik, Braunschweig. - Köln: DLR, 2016. - xxxiv, 258 p.: ill., tab. - (Forschungsberich; 2016-66). - Bibliogr.: p.247-258. - ISSN 1434-8454
Шифр: (Pr 1120/2016-66) 02
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Acknowledgements .............................................. vii
Abstract ....................................................... ix
Kurzfassung .................................................... xi
List of Figures .............................................. xvii
List of Tables .............................................. xxiii
List of Abbreviations and Symbols ............................. xxv
1 Introduction ............................................... 1
1.1 Motivation ................................................. 1
1.2 A Review about Regulatory Requirements for Structural
Integrity .................................................. 3
1.3 Problem Formulation ........................................ 5
1.4 Scientific Questioning and Methodology ..................... 7
1.5 Summary of Contributions ................................... 8
1.6 Thesis Structure .......................................... 10
2 Research Review ........................................... 13
2.1 Flexible Aircraft Modeling and System Identification ...... 13
2.1.1 Regulatory Requirements about the Influence of
the Structural Flexibility ......................... 16
2.2 Flight-Loads Measurement, Modeling and Monitoring ......... 16
2.2.1 Previous Work about Loads Monitoring, System
Identification and Structural Investigations ....... 20
2.3 Concluding Remarks ........................................ 25
3 Airframe Maintenance Process and Costs ...................... 29
3.1 Airframe Maintenance Process .............................. 29
3.2 Airframe Maintenance Costs ................................ 31
3.3 Financial Analysis concerning Airline's Maintenance
Costs ..................................................... 34
3.4 Concluding Remarks ........................................ 37
4 Analysis of Flight Accidents .............................. 39
4.1 Unsatisfactory Loads Monitoring and Fatigue Controlling ... 39
4.2 Concluding Remarks ........................................ 40
5 Mathematical Formulation of the Model ..................... 43
5.1 Equations of Motion for aFlexible Aircraft ................ 43
5.2 Rigid-Body 3-Point Aerodynamic Loads Model ................ 45
5.3 Rigid-Body 7-Point Aerodynamic Loads Model ................ 51
5.4 Aerodynamic Modeling for High Angles of Attack ............ 54
5.5 Structural Effects on the Rigid-Body Aerodynamic Loads .... 55
5.6 Aeroelastic Generalized Forces ............................ 56
5.7 Observation Equations ..................................... 57
5.8 Concluding Remarks ........................................ 64
6 Experimental Scenario and Methodology ..................... 65
6.1 Aircraft Description - Ground and Flight Test Platform .... 65
6.2 Flight Test Methodology ................................... 67
6.2.1 Flight Test Maneuvers .............................. 68
6.2.2 Flight Test Procedures ............................. 71
6.3 Test Instrumentation for Sensor Calibration and Flight
Tests ..................................................... 72
6.4 Strain Sensor Calibration for Flight-Loads Calculation .... 76
6.4.1 Calibration Setup .................................. 76
6.4.2 Calibration Test Points ............................ 77
6.4.3 Physical Modeling and Statistical Tools ............ 78
6.4.4 Calibration Methodology Used in this Work .......... 80
6.5 Concluding Remarks ........................................ 84
7 Sensor Calibration for Calculation of Loads on
a Flexible Aircraft ....................................... 87
7.1 Reference Conditions for the Strain Sensor Calibration .... 87
7.2 Transformation of Strain Gauge Sensor Measurements in
Strain .................................................... 88
7.3 Transformation of FBG Measurements in Pure Mechanical
Strains ................................................... 89
7.4 Sources of Inaccuracies for the Development of the Load
Equations ................................................. 89
7.5 Final Structural Load Equations ........................... 91
7.6 Validation of the Final Structural Load Equations ......... 94
7.7 Local Aerodynamic Load Equations .......................... 95
7.8 Concluding Remarks ....................................... 100
8 Development and Validation of the Multipoint Loads Model
for Flexible Aircraft ...................................... 103
8.1 Data Compatibility Check ................................. 103
8.1.1 Kinematic Relations for Data Compatibility Check .. 104
8.1.2 Data Compatibility Check Performance .............. 107
8.2 Identification of the Multipoint Loads Model for the
DLR Discus-2c ............................................ 107
8.2.1 Accuracy of Loads Prediction Provided by the
Multipoint Loads Model for the Discus-2c .......... 123
8.3 Validation of the Multipoint Loads Model for the DLR
Discus-2c ................................................ 127
8.3.1 Validation in Time Domain ......................... 128
8.3.2 Range of Model Applicability in Frequency Domain .. 135
8.4 Simulation of the Multipoint Loads Model for Real-Time
Applications ............................................. 139
8.5 Limitations and Restrictions of the Real-Time
Multipoint Loads Model ................................... 141
8.6 Concluding Remarks ....................................... 143
9 Conclusions and Future Works ............................. 147
Appendix A - FPR Plots ........................................ 153
Appendix В - Identification Plots ............................. 157
Appendix С - Validation Plots and Results ..................... 203
Appendix D - Identified Model Parameters ...................... 229
Appendix E - Simulation Plots ................................. 239
Bibliography .................................................. 247
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