Topics in Modal Analysis and Testing, Volume 8: Proceedings of the 39th IMAC, a Conference and Exposition on Structural Dynamics 2021

Topics in Modal Analysis & Testing, Volume 8: Proceedings of the 39th IMAC, A Conference and Exposition on Structural Dynamics, 2021, the eighth volume of nine from the Conference, brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of Modal Analysis, including papers on: Operational Modal & Modal Analysis Applications Experimental Techniques Modal Analysis, Measurements & Parameter Estimation Modal Vectors & Modeling Basics of Modal Analysis Additive Manufacturing & Modal Testing of Printed Parts Preface 6 Contents 7 1 A Structural Dynamics Approach to Modeling Human Performance 8 1.1 Background: Banister IR Model 8 1.2 Viscoelastic Model 10 1.3 Results and Discussion 11 1.3.1 Response to Single Impulse 11 1.3.2 Cumulative Response over Season 11 1.3.3 Parameter Fitting 12 1.3.4 Potential for Pedagogical Purposes 13 1.3.5 Potential Future Applications of Vibration Principals to Human Performance 14 1.4 Conclusions 14 References 14 2 Feature Based Monitoring Application for Automatic Crack Detection Using WaveImage 16 2.1 Introduction 16 2.2 Background 17 2.3 Automatic Peak Search 18 2.4 Adjustment of the Automatic Peak Search 19 2.5 Conclusion 20 References 20 3 High Spatial Resolution Modal Parameter Estimation via Low-Cost Fiber Optic Strain Sensors 21 Nomenclature 21 3.1 Introduction 21 3.2 Experimental Setup 22 3.3 Results 22 3.4 Conclusion 26 References 27 4 Machine Learning Vibration-Based Damage Detection and Early-Developed DamageIndicators 29 4.1 Introduction 29 4.2 Methodology 30 4.3 Results 34 4.4 Conclusion 37 References 37 5 Semi-Analytical Analysis for Dynamic Behaviors of Wind Turbine Blades Using Transfer Function Methods 39 5.1 Introduction 39 5.2 Background 40 5.3 Theory and Modeling 41 5.3.1 The Euler–Bernoulli Beam Includes Piezoelectric Patches 42 5.3.2 Analytical Modeling of the Euler–Bernoulli Beam Includes PZT Patches 42 5.4 Assume Mode Method 44 5.4.1 Finite Element Modeling 45 5.4.2 The Wind Turbine Blade Projection on the Euler–Bernoulli Beam 45 5.5 Results and Discussion 47 5.6 Conclusion 48 References 48 6 Evaluating the Mechanical Redesign of a Biped Walking Robot Using Experimental Modal Analysis 50 6.1 Introduction 50 6.2 Mechanical Redesign and System Overview 51 6.3 Experimental Setup 52 6.4 Results 53 6.5 Discussion 54 6.6 Conclusions and Future Works 56 References 56 7 Novel Wirelessly Synchronised Modal Testing of Operational Buildings Using Distributed OCXO High-Precision Data Loggers 58 7.1 Introduction 58 7.2 Oven-Controlled Crystal Oscillator (OCXO) High-Precision Synchronised Data Acquisition System 59 7.3 Forced Vibration Modal Testing in the Use of OCXO-Based Distributed Data Loggers 61 7.3.1 Description of the Test Structure 61 7.3.2 Modal Testing Setup Featuring Wired SA- and Wireless OCXO-Based Distributed Data Loggers 63 7.3.3 Modal Analysis 64 7.4 Modal Testing of Fully Operational CLT Building 67 7.5 Discussion and Conclusions 69 References 69 8 Empirical Fourier Decomposition for Time-Domain Signal Decomposition 70 8.1 Introduction 70 8.2 Reviews of EWT and FDM 71 8.2.1 EWT 71 8.2.2 FDM 74 8.3 EFD 77 8.3.1 Improved Segmentation Technique 77 8.3.2 Construction of an Ideal Filter Bank 78 8.4 Numerical Investigation 79 8.5 Concluding Remarks 81 References 81 9 Vibration Isolation in 3D Printer Using Meta-Structures 83 9.1 Introduction 83 9.2 Bandgap Using the 1D Meta-Structure 83 9.3 Conclusion 85 10 Experimental Modal Analysis Using Nontraditional Response Variables 86 10.1 Introduction 86 10.2 Nomenclature 87 10.3 Theoretical and Experimental Considerations 87 10.3.1 In Vacuo Linear Structural Dynamics 87 10.3.2 Hydroelasticity and Vibroacoustics 88 10.3.3 Experimental Modal Analysis (EMA) Considerations 89 10.4 Illustrative Example 1: In Vacuo Structure Accelerations and Strains 90 10.4.1 Simulated Measured Data 90 10.4.2 Experimental Modal Analysis 92 10.4.3 Strain Viewed as a Surrogate Variable 94 10.5 Illustrative Example 2: Hydroelastic System Accelerations and Fluid Pressures 95 10.5.1 Simulated Measured Data 95 10.5.2 Experimental Modal Analysis 97 10.6 Conclusions 100 A.1 Appendix: The Simultaneous Frequency Domain Method (SFD) 100 A.1.1 Effective Dynamic Systems 100 A.1.2 “Classic” SFD 101 A.1.3 SFD 2018: A Fresh Look at Experimental Modal Analysis 102 References 102 11 Dynamic Behavior of Post-Buckled Fixed-Fixed Composite Skin Panels 103 11.1 Introduction 103 11.2 Experimental Methods 104 11.2.1 Testing Setup 104 11.2.2 Impact Testing 104 11.2.3 Shaker Table Testing 104 11.3 Results and Discussion 106 11.3.1 Determination of Natural Frequencies 106 11.3.2 Changes in Natural Frequency of Post-Buckled Configuration 107 11.3.3 Determination of Minimum g-Loading 108 11.4 Conclusions 109 References 110