Nonlinear Structures & Systems, Volume 1: Proceedings Of The 39th Imac, A Conference And Exposition On Structural Dynamics 2021 (conference . Society For Experimental Mechanics Series) Hardcover

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Preface Contents Pre-test Predictions of Next-Level Assembly Using Calibrated Nonlinear Subcomponent Model 1 Introduction 2 Theory 2.1 Nonlinear Hurty/Craig-Bampton Reduction 2.2 Multi-harmonic Balance 3 Fixture-Pylon Model Calibration 3.1 Fixture-Pylon Finite Element Model 3.2 Extracting Backbone Curves from Experimental Stepped-Sine Data 3.3 Calibration of Nonlinear Elements 3.4 Stepped-Sine Validation 4 Wing-Pylon NNM Computation 4.1 Wing-Pylon Finite Element Model 4.2 NNM 1 Computation 4.3 NNM 2 Computation 5 Conclusions References Nonlinear Variability due to Mode Coupling in a Bolted Benchmark Structure 1 Introduction 2 Experimental Setup and Procedure 3 Results 4 Conclusion References Nonlinear Dynamic Analysis of a Shape Changing Fingerlike Mechanism for Morphing Wings 1 Introduction 2 Theory: Quasi-Static Modal Analysis 3 Finite Element Model of Morphing Wing 4 Simulated Results of Morphing Wing Fem 4.1 Static Preload 4.2 Quasi-Static Modal Analysis 4.3 Reduced Order Model 5 Conclusions and Future Work References Evaluation of Joint Modeling Techniques Using Calibration and Fatigue Assessment of a Bolted Structure 1 Introduction 2 Hardware Description 2.1 Assembly Hardware 3 Experimental Data and Analysis 3.1 Free-Free Modal Data 3.2 Fixed Base Modal Data 3.3 Additional Fixed Base Testing and Characterization of Axial Mode 4 Structural Dynamic Modeling 4.1 Model 1: Solid Bolt and Tied Joint Interface 4.2 Model 2: Tied Joint Bolt and Interface 4.3 Model 3: Single Tied Joint 4.4 Model 4: Tied Data 5 Model Updating 5.1 Initial Study 5.2 Free-Free Comparison 5.3 Fixed Base Comparison 6 Initial Fatigue Assessment 6.1 Background 6.2 Evaluating Uniaxial Fatigue 7 Joint Stiffness Comparison 7.1 Analytical Calculations 7.2 Linear Structural Dynamic Analysis 7.3 Nonlinear Solid Mechanics Analysis 8 Conclusion References A Non-Masing Microslip Rough Contact Modeling Framework for Spatially and Cyclically Varying Normal Pressure 1 Introduction 2 System Modeling 3 Asperity Contact Modeling 4 Results References Finite Elements and Spectral Graphs: Applications to Modal Analysis and Identification 1 Introduction 2 Formulation and Approach: Discretization of the Wave Equation 2.1 Quick Recap of Linear Finite Elements 2.2 Discretization on the Graph Domain 3 Results and Conclusions 4 Future Work References Effects of the Geometry of Friction Interfaces on the Nonlinear Dynamics of Jointed Structure 1 Introduction 2 Methodoloy 2.1 Step 1: Nonlinear Static Analysis 2.2 Step 2: Refined Contact Analysis 2.3 Step 3: Nonlinear Dynamic Analysis 3 Case Study 4 Results 5 Conclusion References Bifurcation Analysis of a Piecewise-Smooth Freeplay System 1 Introduction 2 System's Modeling 3 Nonlinear Characterization 4 Conclusions References Insights on the Bifurcation Behavior of a Freeplay System with Piecewise and Continuous Representations 1 Introduction 2 System Modeling 3 Effectiveness of Continuous Representations for System with Freeplay Nonlinearity 4 Conclusions References Model Updating and Uncertainty Quantification of Geometrically Nonlinear Panel Subjected to Non-uniform Temperature Fields 1 Introduction 2 Theory 2.1 Geometrically Nonlinear Finite Element Model 2.2 Modal Analysis About Thermal Equilibrium 3 Model Correlation of Curved Panel 3.1 Target Experimental Data 3.2 Temperature Field Mapping to FE Model 3.3 Model Updating of Curved Panel at Room Temperature 3.4 Modal Analysis of Curved Panel Subjected to Localized Central Heating 3.5 Model Updating of Curved Panel Subjected to Localized Central Heating 3.6 Effect of Uncertainty in the Panel Model Subjected to Localized Heating 4 Conclusion References On Affine Symbolic Regression Trees for the Solution of Functional Problems 1 Introduction 2 Symbolic Regression Is a Search Problem 3 Enumerating Search Spaces 4 Affine Regression Trees 5 Illustration with a Benchmark Set 6 Conclusions References Comparative Analysis of Mechanical and Magnetic Amplitude Stoppers in an Energy Harvesting Absorber 1 Introduction 2 Nonlinear Reduced-Order Modeling 3 Analysis 4 Conclusions References NIXO-Based Identification of the Dominant Terms in a Nonlinear Equation of Motion 1 Definition of the -Indicators 2 Simulated Black-Box Identification of a Curved Beam 3 Identification of Mode 1 4 Sample Black-Box ID Outcomes from High-Amplitude Vibration Tests 5 Validation of Results 6 Conclusion and Future Work Reference Nonlinear Dynamics and Characterization of Beam-Based Systems with Contact/Impact Boundaries 1 Introduction 2 Experimental Setup and Testing 3 Nonlinear Analysis of Beam with Hard Stoppers 4 Conclusions References Experimental Modal Analysis of Geometrically Nonlinear Structures by Using Response-Controlled Stepped-Sine Testing 1 Introduction 2 Nonlinear Experimental Modal Analysis with RCT and HFS 3 Experiment 4 Discussions and Conclusions References On the Application of the Generating Series for Nonlinear Systems with Polynomial Stiffness 1 Introduction 2 Background Theory and Definitions 2.1 Algebraic Structure 2.2 Iterated Integrals 2.3 Volterra Series 3 The Consolidated Expansion and a Diagrammatic Representation 3.1 Developing the Diagrammatic Representation 4 Generating Series for the Asymmetric Duffing Oscillator 4.1 Shuffle Product of Series Terms 4.2 The Asymmetric Duffing Oscillator 5 Determining System Response 6 Response to Gaussian White Noise 7 Conclusions References A Hybrid Static and Dynamic Model Updating Technique for Structures Exhibiting Geometric Nonlinearity 1 Introduction 2 Hybrid Testing: Theory 3 Static Test and Stiffness Updating 4 Nonlinear Static Test and Model Updating 5 Dynamic Test and Mass Updating 6 Test Setup and Finite Element Modeling 7 Results 8 Conclusion and Future Scope Appendix References Insights on the Dynamical Responses of Additively Manufactured Systems 1 Introduction 2 Additively Manufactured Beams and Experimental Setup 3 Filament Orientation Effects on the Linear Characteristics of PLA-Beam Systems 4 Conclusions References Characterization of Nonlinearities in a Structure Using Nonlinear Modal Testing Methods 1 Introduction 2 Theoretical Background 3 Phase-Locked Loop 4 Software Phase-Locked Loop 5 Test Rig Details 6 Results 7 Conclusion and Future Work References Challenges of Characterizing Geometric Nonlinearity of a Double-Clamped Thin Beam Using Nonlinear Modal Testing Methods 1 Introduction 2 Theoretical Background 3 Phase-Locked Loop: Theory and Implementation 4 Test Structure and Instrumentation Details 5 Results 6 Conclusion and Future Work References Establishing the Exact Relation Between Conservative Backbone Curves and Frequency Responses via Energy Balance 1 Introduction 2 Prediction of Forced-Damped Responses from the Conservative Limit 3 Conclusion References Joint Interface Contact Area Predictions Using Surface Strain Measurements 1 Introduction 2 Experimental Specimen 3 Results Reference Towards Compact Structural Bases for Coupled Structural-Thermal Nonlinear Reduced Order Modeling 1 Introduction 2 Coupled Structural-Thermal NLROM 3 Enrichment for Two-Temperature-Field Scenario 4 Methods for Construction of Compact Enriched Bases 4.1 Method of Progressive POD 4.2 Method of Static Condensation 5 Comparison of Three Enriched ROMs with Nastran 6 Conclusions References Ensemble of Multi-time Resolution Recurrent Neural Networks for Enhanced Feature Extraction in High-Rate Time Series 1 Introduction 2 Algorithm Architecture 3 Simulations on Drop Tower Data 4 Conclusion References Modelling the Effect of Preload in a Lap-Joint by Altering Thin-Layer Material Properties 1 Introduction 2 Experimental Analysis of Lap-Joint 3 The Modified Thin-Layer Approach 4 3D Detailed Model 5 2D Equivalent Model 6 Conclusion References Nonlinear Structures & Systems, Volume 1: Proceedings Of The 39th Imac, A Conference And Exposition On Structural Dynamics, 2021, The First 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 Nonlinear Dynamics, Including Papers On: Nonlinear Reduced-order Modeling Jointed Structures: Identification, Mechanics, Dynamics Experimental Nonlinear Dynamics Nonlinear Model & Modal Interactions Nonlinear Damping Nonlinear Modeling & Simulation Nonlinearity & System Identification