A Virtual Testing Approach for Honeycomb Sandwich Panel Joints in Aircraft Interior (eBook)

Vorwort 8
Zusammenfassung 9
Table of contents 10
Abbreviations 13
Nomenclature 15
1 Introduction 16
1.1 Motivation 16
1.2 Thesis objectives 17
1.3 Thesis structure 17
2 State of the art 19
2.1 Sandwich structures 19
2.1.1 Face sheets 19
2.1.2 Core 21
2.1.3 Bonded sandwich panel 22
2.1.4 Failure modes 25
2.2 Sandwich structure joints 26
2.2.1 Inserts 26
2.2.2 Panel edges 29
2.2.3 Novel joint designs 30
2.3 Computational analysis 31
2.3.1 Finite Element Method 33
2.3.2 Literature survey on sandwich panel joint modelling 36
2.4 Virtual testing 37
2.5 Assessment of the state of the art and need for further research 44
3 Overall concept of mechanical characterization 47
4 Mechanical characterization on constituent level 49
4.1 Sandwich core 49
4.1.1 Materials 50
4.1.2 Experimental analysis 53
4.1.3 Numerical modelling on meso scale 58
4.1.4 Numerical modelling with 3D-contiuum elements 73
4.1.5 Conclusion 76
4.2 Face sheets 76
4.2.1 Experimental analysis 78
4.2.2 Numerical modelling and calibration 79
4.3 Adhesives 82
4.3.1 Experimental analysis 82
4.3.2 Numerical modelling and calibration 86
5 Mechanical characterization on structural element level 87
5.1 Panel flexure 87
5.1.1 Experimental analysis 89
5.1.2 Numerical analysis 93
5.2 In-plane shear 101
5.2.1 Experimental analysis 101
5.2.2 Numerical analysis 102
5.3 Additional test methods 105
6 Mechanical characterization on sub-component level 108
6.1 Threaded inserts perpendicular to the face sheet 108
6.1.1 Out-of-plane tension (pull-out) 109
6.1.2 In-plane tension (shear) 112
6.2 L-Joints 113
6.2.1 L-Joint bending test 114
6.2.2 L-Joint shear test 115
7 Virtual testing approach for sandwich panel joints 117
7.1 Overview 117
7.2 Phase 1 - Problem analysis 118
7.3 Phase 2 - Definition of model framework 122
7.4 Phase 3 - Model development 126
7.4.1 Investigation 127
7.4.2 Building blocks 137
7.4.3 Modelling database 148
7.5 Phase 4 - Application of virtual test 148
7.6 Summary 152
7.7 Validation based on different joint configurations 153
7.7.1 Partially potted inserts 153
7.7.2 Corner joints 160
7.7.3 Conclusion 165
8 Development of novel sandwich panel joints 166
8.1 Virtual testing of design alternatives 168
8.2 Validation by experimental investigation 171
9 Summary and outlook 173
Literature 175
Appendix A – Constituent level 189
A1 Implemented material models of Nomex honeycomb 189
A2 Implemented material models for face sheets 193
A3 Implemented material models for adhesives 197
Appendix B – Structural element level 202
B1 Sandwich bending test details 202
B2 Comparison of modelling approaches in case of bending 204
B3 Frame shear test details 205
Appendix C – Sub-component level 206
C1 Damage progression for pull-out test on fully potted insert 206
C2 Implemented cohesive behavior of potting-face contact 207
C3 Experimental results in novel design study 208
Lebenslauf 210