 | Kling A. Contributions to improved stability analysis for design of thin- walled composite structures. - Deutsches Zentrum für Luft- und Raumfahrt Institut für Faserverbundleichtbau und Adaptronik, Braunschweig. - Köln: DLR, Bibliotheks- und Informationswesen, 2010. - vi, 123 p.: ill., graph. - (Forschungsbericht; 10-01). - Incl. bibl. ref. - ISSN 1434-8454
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List of Figures ................................................ iv
List of Tables ................................................ vii
1 Introduction ................................................. 1
1.1 Motivation .............................................. 1
1.2 Scope of the Work ....................................... 3
2 Simulation and Experimental Validation of Stiffened
Composite Panels ............................................. 4
2.1 Introduction ............................................ 4
2.2 Literature Review ....................................... 4
2.2.1 A Brief History of Stability Analysis ............ 4
2.2.2 A Brief Review on Composite Material ............. 6
2.2.3 Experimental Investigations on Buckling and
Postbuckling of Stiffened Composite Panels ....... 7
2.2.4 Numerical Investigations on Buckling and
Postbuckling of Stiffened Composite Panels ....... 9
2.2.5 Validation and Verification ..................... 10
2.3 Structural Stability Phenomena ......................... 11
2.3.1 Bifurcation Buckling ............................ 13
2.3.2 Limit Point Buckling ............................ 15
2.4 Stability Design Scenario for Stiffened Curved CFRP
Panels ................................................. 17
2.5 Experiment ............................................. 18
2.5.1 Design of the Test Structures ................... 20
2.5.2 Test Structure .................................. 22
2.5.3 Preparation of the Test Structure ............... 24
2.5.4 Test ............................................ 30
2.5.5 Results ......................................... 32
2.6 Analysis ............................................... 34
2.6.1 Eigenvalue Buckling Analysis .................... 35
2.6.2 Time Independent Solution Methods ............... 36
2.6.3 Time Dependent Solution Methods ................. 43
2.6.4 Finite Element Model ............................ 47
2.6.5 Simulation Procedure ............................ 49
2.6.6 FE Analysis ..................................... 52
2.6.6.1 Newton-Raphson Method with Artificial
Damping ................................ 52
2.6.6.2 Arc-Length (modified Riks) Method ...... 56
2.6.6.3 Dynamic Explicit Finite Difference
Method ................................. 58
2.6.6.4 Summary of the Non-linear FA
Analysis ............................... 60
2.7 Validation ............................................. 62
2.7.1 Introduction .................................... 62
2.7.2 Validation Process .............................. 63
2.7.3 Results ......................................... 66
2.8 Validation Assessment .................................. 70
2.9 Summary ................................................ 72
2.10 Conclusions and Outlook ................................ 72
3 Hybrid Subspace Analysis Procedure .......................... 75
3.1 Introduction ........................................... 75
3.2 Literature Review ...................................... 75
3.3 Outline of the Method .................................. 79
3.4 Selection and Determination of Global Shape
Functions .............................................. 82
3.4.1 Deformed Structure of the Last Converged
Full System Increment ........................... 83
3.4.2 Buckling Modes .................................. 83
3.4.3 Path-Derivatives ................................ 84
3.5 System Reduction ....................................... 85
3.6 Flow-Chart of the Computational Procedure .............. 86
3.7 Numerical Examples ..................................... 91
3.7.1 Example 1 ....................................... 93
3.7.2 Example 2 ....................................... 94
3.7.3 Example 3 ....................................... 98
3.7.4 Example 4 ....................................... 99
3.8 Summary ............................................... 101
3.9 Conclusion and Outlook ................................ 102
Bibliography .................................................. 105
Appendix A .................................................... 116
Appendix В .................................................... 118
Appendix С .................................................... 122
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