 | Siemann M.H. Numerical and experimental investigation of the structural behavior during aircraft emergency landing on water: Diss. … Dr.-Ing. / Deutsches Zentrum für Luft-und Raumfahrt, Institut für Bauweisen- und Strukturtechnologie, Stuttgart. - Köln: DLR, 2016. - XII, 184 p.: ill., tab. - (Forschungsbericht; 2016-42). - Res also Germ. - Bibliogr.: p.170-184. - ISSN 1434-8454
Шифр: (Pr 1120/2016-42) 02
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Nomenclature .................................................. vii
Abstract ....................................................... ix
Kurzfassung .................................................... xi
1 Introduction ............................................... 1
1.1 Background and Motivation .................................. 1
1.2 Objectives and Structure ................................... 4
2 Fundamentals and State of the Art .......................... 7
2.1 Ditching and Crash on Water ................................ 7
2.2 Ditching Certification .................................... 12
2.2.1 Requirements ....................................... 12
2.2.2 Procedures ......................................... 14
2.3 Methods for Ditching Analysis ............................. 16
2.3.1 Accident Investigations ............................ 17
2.3.2 Ditching Experiments ............................... 18
2.3.3 Analytical, Semi-Analytical and Hybrid Approaches .. 23
2.3.4 Advanced Numerical Simulations ..................... 26
2.4 Coupled SPH-FE Approach ................................... 33
2.4.1 Fundamentals ....................................... 33
2.4.2 Coupling ........................................... 34
2.4.3 Selected Applications .............................. 35
2.5 Smoothed Particle Hydrodynamics ........................... 37
2.5.1 Fundamentals ....................................... 37
2.5.2 Governing Equations ................................ 40
2.5.3 Computational Aspects .............................. 43
2.6 Summary of Identified Challenges and Open Questions ....... 44
2.7 Detailed Objectives ....................................... 45
3 Guided Ditching Experiment ................................ 47
3.1 Introduction .............................................. 47
3.2 Description of Experiment ................................. 49
3.2.1 Test Facility ...................................... 49
3.2.2 Trolley Assembly. Specimens, and Instrumentation ... 50
3.2.3 Test Program and Procedure ......................... 53
3.3 Test Results .............................................. 54
3.3.1 General Description ................................ 54
3.3.2 Relation of Hydrodynamic and Structural Response ... 59
3.3.3 Effects of Impact Conditions and Panel Curvature ... 62
3.3.4 Effects of Structural Deformation .................. 69
3.4 Summary and Discussion ............................... 75
4 Guided Ditching Simulation ................................ 77
4.1 Introduction .............................................. 77
4.2 Structural Model .......................................... 78
4.2.1 Guide Track ........................................ 78
4.2.2 Trolley and Panel .................................. 81
4.2.3 Instrumentation of Numerical Model ................. 84
4.3 Fluid Model ............................................... 86
4.3.1 Hydrodynamic Model ................................. 86
4.3.2 Modeling Strategies for the Fluid Domain ........... 95
4.3.3 Particle Resolution ............................... 103
4.3.4 Initial Particle Distribution ..................... 105
4.4 Fluid-Structure Interaction .............................. 113
4.5 Summary of Developed Simulation Model ............... 113
5 Validation and Verification Studies ...................... 117
5.1 Parameter Studies ........................................ 117
5.1.1 Impact Conditions and Panel Curvature ............. 118
5.1.2 Structural Deformation ............................ 123
5.2 Investigation of Structural Behavior ..................... 129
5.2.1 Key Mechanisms of Structural Response ............. 129
5.2.2 Analysis of Strain Distribution and Local Strain
Gradients ......................................... 132
5.3 Discussion of Results .................................... 137
5.3.1 Capabilities and Limitations ...................... 137
5.3.2 Investigation of Structural Behavior .............. 139
6 Conclusion and Outlook ................................... 141
6.1 Contributions and Conclusions ............................ 141
6.2 Future Work .............................................. 145
A Guided Ditching Experiment ............................... 149
A.l Facility Tolerances ................................. 149
A.2 Overview of Instrumentation ......................... 149
A.3 Test Matrix ......................................... 152
A.4 Model for Estimation of Air Cushion ................. 153
A.5 Supplementary Results: Effects of Structural
Deformation ......................................... 154
В Guided Ditching Simulation ............................... 155
B.l Hard- and Software .................................. 155
B.2 Material Input Data ................................. 156
B.3 Results with Two-Phase Cavitation Model ............. 158
B.4 Results of SPH Domain Size Investigation ............ 160
B.5 Results of SPH Resolution Study in 2D ............... 161
B.6 Non-Uniform Particle Distributions .................. 162
С Validation and Verification Studies ...................... 167
C.l Exemplary Pressure Time Histories ................... 167
C.2 Supplemental Results: Parameter Studies ............. 168
C.3 Analysis of Panel Deformation ....................... 170
Bibliography .................................................. 171
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