Vibration Based Structural Health Monitoring of Composite Skin-Stiffener Structures

Vibration-Based Structural Health Monitoring of Composite Skin-Stiffener Structures
Ted Ooijevaar
Contents
Summary i
Samenvatting iii
Nomenclature ix
1 Introduction 1
1.1 Background and motivation . 1
1.2 Composite structures . 3
1.2.1 Fiber reinforced plastics . 3
1.2.2 Damage types . 4
1.2.3 Damage classification 5
1.3 Structural health monitoring 6
1.3.1 General . 6
1.3.2 Classifications . 7
1.3.3 Techniques . 9
1.3.4 Major technology gaps 11
1.4 Objective and scope 12
1.5 Outline . 14
References 15
2 Overview of vibration based damage identification methods 19
2.1 Introduction 20
2.2 Generalized description damaged system . 20
2.3 Literature overview vibration based methods . 22
2.4 Damage feature selection 24
2.4.1 Effect of damage on dynamic properties . 25
2.4.2 Information condensation 30
2.5 Concluding remarks . 35
References 35
vvi Contents
3 Vibration based structural health monitoring of a composite T-beam 39
3.1 Introduction 40
3.2 The modal strain energy damage index algorithm 41
3.3 Composite T-beam structure . 43
3.4 Experimental analysis of a sub-structure . 44
3.4.1 Experimental outline . 44
3.4.2 Set-up and vibration measurements 45
3.4.3 Results . 46
3.5 Conclusions 54
References 56
4 Damage identification in skin-stiffener structures based on curvatures 59
4.1 Introduction 60
4.2 Composite skin-stiffener structures . 61
4.3 Damage identification procedure 65
4.4 Experimental set-up and signal processing 69
4.5 Experimental results . 71
4.5.1 Two stiffener structure with damage scenario I and II 71
4.5.2 Three stiffener structure with damage scenario III 74
4.6 Discussion . 78
4.7 Conclusions 79
References 81
5 Nonlinear dynamic behavior of an impact damaged skin-stiffener structure 85
5.1 Introduction 86
5.2 Composite skin-stiffener structure . 87
5.3 Experimental work 88
5.3.1 Set-up and signal processing 89
5.3.2 Initial global dynamic characterization 89
5.3.3 Harmonic waveform distortion . 92
5.3.4 Damage induced dynamic mechanisms 94
5.3.5 Spatial effects . 98
5.3.6 Influence of excitation frequency 101
5.4 Discussion . 102
5.4.1 Underlying physical phenomena 102
5.4.2 Higher harmonics 104
5.5 Conclusions & future prospects . 106
References 107Contents vii
6 Vibro-acoustic modulation based damage identification 109
6.1 Introduction 110
6.1.1 Background and motivation . 110
6.1.2 Vibro-acoustic modulation concept 110
6.1.3 Objective and outline 112
6.2 Theoretical description 113
6.2.1 Two-tone forced vibration of a nonlinear system . 113
6.2.2 Signal decomposition approach 115
6.2.3 Nonlinear response characteristics . 116
6.3 Experimental work 118
6.3.1 Composite skin-stiffener structure . 118
6.3.2 Experimental set-up . 118
6.3.3 Experimental procedure . 120
6.4 Experimental results and discussion 122
6.4.1 Response decomposition 123
6.4.2 Spatial results . 125
6.4.3 Underlying dynamic behavior . 130
6.5 Conclusions & future prospects . 131
References 133
7 Discussion 135
7.1 Design of an SHM strategy . 135
7.1.1 Scenario based design procedure 136
7.1.2 Combination of approaches . 140
7.2 Application of vibration based SHM 141
7.2.1 Integrated sensing 142
7.2.2 Operational and environmental effects 145
References 145
8 Conclusions and recommendations 149
8.1 Conclusions 149
8.2 Recommendations 151
A Dynamics based nondestructive testing techniques 153
B Damage features and classifiers 157
C Hilbert transform 163
Dankwoord 165
Publications 16 .
كلمة سر فك الضغط : books-world.net
The Unzip Password : books-world.net