Special Topics in Structural Dynamics & Experimental Techniques, Volume 5

Preface: SEM 2022 IMAC XL – Volume 5	6
Contents	7
1 Multi-Cellular Damping for Composite Material Applications	9
1.1 Introduction	9
1.2 Background	10
1.3 Analysis	10
1.4 Conclusion	12
References	14
2 Novel Data Acquisition Utilising a Flask Python Digital Twin Operational Platform	15
2.1 Introduction	15
2.2 Digital Twin Operational Platform	15
2.2.1 DTOP-Cristallo	16
2.3 Experimental System	17
2.3.1 Setup	17
2.3.2 Code	17
2.4 Results	19
2.5 Conclusions	19
References	20
3 Model Validation for Combined Inertial Acceleration and Vibration Environments	22
3.1 Introduction	22
3.2 Unit Description	23
3.2.1 Design	23
3.2.2 Centrifuge Setup	24
3.3 Experimental Characterization	24
3.3.1 Modal Testing	25
3.3.2 Vibrafuge Testing	28
3.4 Finite Element Analysis	28
3.4.1 Modal Analysis	29
Model Calibration	29
Preloaded/Handoff Modal	30
3.4.2 Random Vibration Analysis	31
Loading Cases	32
Random Vibration Loading	34
Random Vibration Results	35
3.5 Conclusion	38
A.1 Appendix	39
References	40
4 Modal Testing with Piezoelectric Stack Actuators	41
4.1 Introduction	41
4.2 Transfer Function Derivation	42
4.3 Experimental Application	44
4.4 Conclusions	46
References	46
5 Generative Adversarial Networks for Labelled Vibration Data Generation	47
5.1 Introduction	47
5.1.1 Problems	47
5.1.2 Background	48
5.1.3 Objective of the Study	48
5.2 Workflow	48
5.2.1 Data and Equipment	48
5.2.2 Data Preprocessing	48
5.2.3 Model Architecture	49
5.2.4 Fine-Tuning for Training	49
5.2.5 Evaluation and Interpretation of the Results	50
5.3 Conclusion	54
References	54
6 Validation of an Impulse Response Filter for Impact Force Reconstruction on a Hammer Drill	57
6.1 Introduction	57
6.2 Impulse Response Filter	58
6.3 Validation Case	59
6.4 Conclusion	61
References	62
7 Determination of Nonlinear Joint Forces and Nonlinear Identification of Jointed Connections Using FRFs	63
7.1 Introduction	63
7.2 Theory	64
7.3 Results	65
7.4 Conclusion	66
References	66
8 Investigation of Using Log-Spectrum Averaging (Cepstral Averaging) for Blind Reconstruction of an Unknown Impact Input Force	68
8.1 Introduction	68
8.2 Methodology	69
8.3 Simulation Results	70
8.3.1 FE Model and Simulation Parameters	71
8.3.2 Blind ILP Result (Noise-Free Case)	71
8.4 Discussion	72
8.5 Conclusion	72
References	73
9 The Application of a Force Identification Method Based on Particle Swarm Optimization to Compression Steel Bars	74
9.1 Introduction	74
9.2 Theoretical Model	75
9.3 Experimental Setup	77
9.4 Experimental Results	79
9.5 Conclusion	80
Appendix	82
References	84
10 Degree of Freedom Selection Approaches for MIMO Vibration Test Design	85
Introduction	85
Theory	86
Sensor Selection Approach	86
Optimal Experimental Design	87
Test Design	89
Model	89
Field Environment	89
Laboratory Conditions	89
Analysis Steps	91
Results	91
Single Example – Nominal Laboratory Model – Nominal Field Model – Environment A	91
Overall Performance	92
Model Variation	93
Additional Considerations	94
Conclusions	94
References	94
11 Vibration Mitigation of Bladed Structures Using Piezoelectric Digital Vibration Absorbers	95
Introduction	95
Background	96
Results	97
Conclusion	98
References	98
12 An Open-Source Automatic Modal Hammer Suitable for Studying Nonlinear DynamicalSystems	99
Introduction	99
Methods	100
Results	100
References	101
13 Crack Diagnosis and Prognosis of Miter Gates Based on a Global-Local Model and Image Observations	102
Introduction	102
IGL Algorithm	102
Image-Based Measurements	103
Online Diagnosis and Prognosis	103
Results	104
Conclusion	105
References	105
14 A Hierarchical Filtering Approach for Online Damage Detection Using Parametric Reduced-Order Models	106
Introduction	106
Methodology	106
Results	107
Conclusions	108
References	108
15 A Tutorial on an Open-Source Python Package for Frequency-Based Substructuring and Transfer Path Analysis	109
Introduction	109
Recap of the Existing pyFBS Features	110
Test Structure Datasets	110
3D Display	111
FRF Synthetization	111
Virtual Point Transformation	112
System-Equivalent Model Mixing	112
Source Characterization with the In-Situ TPA	113
Additional Features of pyFBS	113
Singular Vector Transformation	113
Operational System Identification	114
Conclusions	119
References	119
16 Miniature Underwater Robot – An Experimental Case Study	120
Introduction	120
Experiments and Analysis	121
Conclusion	122
References	123
17 Benefits of Using a Portable Coordinate Measurement Machine to Measure a Modal Test Geometry	124
Introduction	124
Standard Geometry Generation Methods	125
Basic Process for Generating Test Geometries with a PCMM	125
Defining the Locations of Triaxial Accelerometers	127
Defining the Locations of Uniaxial Accelerometers	127
Converting the Probe Data into a Test Geometry	129
Measuring Probe Data on Large Structures	131
Comments on Accuracy	131
Identifying Specified Measurement Locations	132
Benefits from Using the PCMM and Geometry Generation Script	133
Conclusions	135
References	135

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