Special Topics in Structural Dynamics & Experimental Techniques, Volume 5: Proceedings of the 39th IMAC, A Conference and Exposition on Structural ... Society for Experimental Mechanics Series)

Dynamics of Coupled Structures , Volume 5: Proceedings of the 39th IMAC, A Conference and Exposition on Structural Dynamics, 2021, the fourth 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 the Dynamics of Coupled Structures, including papers on: Methods for Dynamic Substructures Applications for Dynamic Substructures Interfaces & Substructuring Frequency Based Substructuring Transfer Path Analysis Preface Contents 1 A Comparative Study of Joint Modeling Methods and Analysis of Fasteners Nomenclature 1.1 Introduction 1.2 Modeling Methods for Fastener Joints 1.2.1 Tied Surfaces at Joint: Tied Contact Method 1.2.2 Spring Model of Fastener: Spring Method 1.2.3 Beam Model of Fastener: Beam Method 1.2.4 Solid Model of Fastener: Plug Method 1.2.5 Cylinder of Solid Elements: Ring Method 1.2.6 Including Preload and Fastener Properties: Ring-Beam Method 1.2.7 Frustrum Calculation 1.3 Example Problem 1.4 Results 1.4.1 Modal Comparisons 1.4.2 Random Vibration Comparisons 1.5 Conclusion References 2 Historical Perspective of the Development of Digital Twins 2.1 Background 2.2 Pre-delivery Usage 2.2.1 Design Usage 2.2.2 Manufacturing Usage 2.3 Asset Management Usage 2.3.1 Life-Cycle Determination 2.3.2 VVUQ 2.4 Digital Twin Hierarchy 2.5 Conclusions References 3 Distributed Home Labs at the Time of the Covid 3.1 Introduction 3.2 Experimental Laboratories as a Tool for Practitioner Engineering 3.3 The New Revolution Offered by Microelectronics 3.4 The Smartphone: A Complete Measurement Lab 3.5 Some Preliminary Attempts with Small Groups on Research Projects 3.6 Some of the Most Interesting Projects 3.7 Final Remarks and Conclusions References 4 Closed-Form Solutions for the Equations of Motion of the Heavy Symmetrical Top with One Point Fixed 4.1 Background 4.2 Derivation of the EOM 4.3 The Cubic Polynomial f(u) 4.4 General Closed-Form Solution of the EOM 4.5 Closed-Form Solution for h == 1 4.6 Closed-Form Solution for h == 2 4.7 Conclusion References 5 Equations of Motion for the Vertical Rigid-Body Rotor: Linear and Nonlinear Cases 5.1 Definition of the Equations of Motion 5.2 Kinetic Energy of a Rigid-Body Rotor 5.3 Nonlinear Generalized Forces 5.4 Linear Form of the EOM 5.5 Results from the Linear Example 5.6 Procedure for Solving of the Nonlinear EOM 5.7 Results for the Nonlinear Example 5.8 Example That Exhibits Chaotic Behavior 5.9 Duffing Equation 5.10 Conclusions A.1 Appendix A References 6 Vibration Control in Meta-Structures Using Reinforcement Learning 6.1 Introduction 6.2 Q-Learning Algorithm Framework 6.3 Conclusion References 7 Using Steady-State Ultrasonic Direct-Part Measurements for Defect Detection in Additively Manufactured Metal Parts 7.1 Introduction 7.1.1 Defects in Additively Manufactured Parts 7.1.2 Quality Control and Non-destructive Evaluation 7.1.3 Acoustic Wavenumber Spectroscopy 7.2 Background 7.2.1 Materials 7.2.2 In Situ Data Acquisition Process 7.3 Analysis 7.3.1 Post-build Data Processing 7.3.2 Defect-Indicative Features 7.3.3 X-Ray Computed Tomography Labeling 7.3.4 Results 7.3.5 Future Work 7.4 Conclusion A.1 Appendix A: Montage of Figures References 8 Toward Developing Arrays of Active Artificial Hair Cells 8.1 Introduction 8.2 Array of Self-Sensing Artificial Hair Cells 8.3 AHC Array Simulation Results 8.4 AHC Array Simulation Results 8.5 Conclusion References 9 Challenges Associated with In Situ Calibration of Load Cells in Force-Limited Vibration Testing 9.1 Introduction 9.2 Test Setup 9.3 Apparent Mass Calculation 9.4 Load Cell Summing Implications on In Situ Calibration 9.5 Conclusion References