ABBREVIATIONS ................................................... 9
ZUSAMMENFASSUNG ................................................ 11
ABSTRACT ....................................................... 13
1 INTRODUCTION ................................................ 14
l.l Objective and structure of the thesis .................. 18
2 REVIEW ON CRASHWORTHINESS RESEARCH - STATE OF THE ART ....... 21
2.1 Review on crashworthiness research ..................... 21
2.2 Review on simulation methodologies ..................... 31
2.3 Identification of open questions - definition of the
thesis ................................................. 36
3 ASPECTS OF THE KINEMATICS MODEL APPROACH .................... 39
3.1 Basic approach of the Kinematics Model ................. 39
3.2 Macro modelling of crash devices ....................... 41
3.2.1 Selection of a macro element .................... 42
3.2.2 Macro architecture for axial crushing ........... 43
3.2.3 Macro architecture for frame bending ............ 45
3.2.4 Macro architecture for cargo-crossbeam failure .. 46
3.2.5 Macro architecture for the passenger crossbeam
connection ...................................... 47
3.3 Definition of Kinematics Model output data ............. 48
3.3.1 Output definition of macroelements .............. 49
3.3.2 Output definition of structural loads ........... 50
3.3.3 Output definition of injury risks ............... 51
3.4 Further modelling aspects .............................. 53
3.4.1 Refinement of the sub-cargo area modelling ...... 53
3.4.2 Parameterisation of the Kinematics Model ........ 55
4 DETAILED INVESTIGATION OF FRAME FAILURE MODELLING ........... 57
4.1 Positioning of the 'kinematic hinges' .................. 58
4.2 Pre-failure behaviour of a frame-stringer-skin
structure .............................................. 65
4.2.1 Potential failure initiations of
a frame-stringer-skin structure loaded under
pure bending .................................... 66
4.2.2 Elastic behaviour of a frame-stringer-skin
structure ....................................... 69
4.3 Post-failure behaviour of a frame-stringer-skin
structure .............................................. 73
4.3.1 Frame failure of typical fuselage design ........ 73
4.3.2 Frame failure of non-typical fuselage design .... 76
4.3.3 Failure behaviour of CFRP frame structures ...... 80
4.3.4 Outcomes of the investigation of the post-
failure behaviour ............................... 82
4.4 Influence of the kinematic hinge architecture on
lateral frame stability ................................ 83
4.5 Influence of the discretisation ........................ 88
4.6 Influence of the bending-compression ratio ............. 94
4.6.1 Identification of typical bending-compression
ratios .......................................... 95
4.6.2 Influence of the bending-compression ratio on
the kinematic hinge behaviour ................... 97
4.6.3 Influence of the bending-compression ratio on the
failure behaviour of a frame-stringer-skin
structure ...................................... 102
4.7 Summary - the final kinematic hinge macro
architecture .......................................... 103
5 IMPLEMENTATION OF A USER ELEMENT FOR FRAME FAILURE
MODELLING .................................................. 106
5.1 Requirements for an improved macro element ............ 107
5.2 Implementation of the user element .................... 112
5.3 Verification on the quasi-single element level ........ 117
5.4 Verification on the reference model level ............. 120
5.5 Summary and outlook ................................... 123
6 DEVELOPMENT OF A CRASHWORTHY COMPOSITE FUSELAGE DESIGN -
CRASH SCENARIO ASSESSMENT .................................. 124
6.1 Natural crash kinematics .............................. 125
6.2 Development of crash scenario A & В ................... 129
6.3 Assessment of crash scenario A & В .................... 136
7 DEVELOPMENT OF A CRASHWORTHY COMPOSITE FUSELAGE DESIGN -
CRASH SCENARIO DEVELOPMENT ................................. 141
7.1 Definition of structural allowables ................... 142
7.2 Analytical consideration of the crash zone ............ 146
7.3 Approach for the crash scenario development ........... 149
7.4 Crash scenario development ............................ 152
7.4.1 Crash kinematics optimisation .................. 153
7.4.2 Structural adaptation .......................... 159
7.4.3 Final crash scenario ........................... 163
7.5 Modification of the final crash scenario - the
ovalisation effect .................................... 166
7.6 Summary - definition of the final macro input
characteristics ....................................... 171
8 DEVELOPMENT OF A CRASHWORTHY COMPOSITE FUSELAGE DESIGN -
EXPERIMENTAL INVESTIGATION ON THE DESIGN OF CRASH DEVICES .. 174
8.1 Axial crushing tests .................................. 175
8.2 Frame bending tests ................................... 184
9 CONCLUSION AND OUTLOOK ..................................... 192
9.1 Methodology of the finite element modelling approach .. 192
9.2 Methodology of the crash design process ............... 194
9.3 Outlook ............................................... 195
Al APPENDIX OF CHAPTER 2 ...................................... 197
Al.l The finite element method in the scope of this
thesis ................................................ 197
A2 APPENDIX OF CHAPTER 4 ...................................... 201
A2.1 Analysis of pre-failure behaviour - description of
the numerical model ................................... 201
A3 APPENDIX OF CHAPTER 5 ...................................... 203
A3.1 List of property parameters ........................... 203
A3.2 List of solution-dependent variables (SOV) ............ 206
A3.3 Structogram of the calculation of internal forces ..... 207
A3.4 Definition of the reference model ..................... 214
A4 APPENDIX OF CHAPTER 6 ...................................... 216
A4.1 Definition of the fuselage design and the Kinematics
Model used for the crash scenario assessment .......... 216
A4.1.1 Assumptions for the macro input
characteristics ................................ 218
A4.1.2 Numerical parameters ........................... 220
A4.2 Further simulation results of the assessment study
of the crash scenarios ................................ 220
A4.2.1 Change of sign of the moment load in the
frame of scenario В ............................ 220
A4.2.2 Rotation angle of the absorbing kinematic
hinges in both scenarios ....................... 221
A4.2.3 Structural load-frame inner flange strains of
both scenarios ................................. 222
A4.2.4 Tensile loads in the vertical support struts ... 222
A4.2.5 Simulation results of the robustness cases
for scenario A ................................. 223
A4.2.6 Simulation results of the robustness cases
for scenario В ................................. 230
A5 APPENDIX OF CHAPTER 7 ...................................... 236
A5.1 Definition of the fuselage design and the Kinematics
Model used for the crash scenario development ......... 236
A5.2 Further results of the final crash scenario ........... 239
A5.3 Further results of the ovalisation effect ............. 246
A5.4 Further details of the metallic frame model ........... 251
A5.5 Determination of an optional trigger load level for
the vertical support struts ........................... 252
A6 APPENDIX OF CHAPTER 8 ...................................... 254
A6.1 Remarks to the development of a test setup for axial
crushing tests ........................................ 254
A6.2 Test matrix of the axial crushing test programme ...... 258
A6.3 Remarks to the development of a test setup for frame
bending tests ......................................... 259
A6.4 Test matrix of the frame bending test programme ....... 261
BIBLIOGRAPHY .................................................. 263
| 
