bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling and Chatter Suppression With Ultra-Precision in Dynamic Turning Metal Cutting Process
Authors: Pan Jingchuan , Su Chun-Yi 
Published: November 2020

Abstract
In turning metal cutting, the occurrence of self-excited vibration, so called chatter, is undesirable as it gives rise to production problems, causing detrimental effects on the machined surface finish and decreasing the machining efficiency. In this paper, in order for chatter suppression, a piezoactuator is introduced for the regulation of the machine tool displacement and the metal cutting system is modeled as a class of uncertain linear system with hysteresis and time delay. In order to overcome the chatter due to the hysteresis and time delay during the cutting process, an robust adaptive controller for the metal cutting system of ultra-precision is proposed and the simulation results shows that the proposed adaptive controller significantly eliminates the chatter phenomena.
Structure-Borne Vibro-Impact Resonances and Periodic Green Functions
Authors: Babitsky V. I. , Veprik A. M. 
Published: November 2020

Abstract
Impact interactions can excite complex nonlinear resonant responses in structures subjected to simple periodic excitation. The specific features of these resonances are concentration of high harmonics in corresponding waveforms, dependence of their behaviour on parameters and initial conditions, synergistic spatial effects, and generation of essential forces and stresses. An effective approach to analysis of these resonances was developed using special functions, called periodic Green functions. An introduction of these functions allows the regular study of resonant phenomena in vibro-impact systems based on structural presentations and without reference to differential equations of motion. The paper reviews some results on the application of periodic Green functions for analysis of resonant phenomena in vibro-impact structures with lumped and distributed parameters. The physical experiments support the results of analysis.
Nonlinear Transient Localization and Beat Phenomena due to Backlash in a Coupled Flexible System
Authors: Ma Xianghong , Vakakis Alexander F. 
Published: November 2020

Abstract
Transient nonlinear localization and beat phenomena are studied in a system of two rods coupled with a nonlinear backlash spring. The method of Karhunen-Loeve (K-L) decomposition is used to reduce the order of the dynamics, and to study nonlinear effects by considering energy transfers between leading K-L modes. The computed K-L modes are used to discretize the governing partial differential equations, thus creating accurate and computationally efficient low-dimensional nonlinear models of the system. Reconstruction of transient nonlinear responses using these low dimensional models reveals the accuracy of the order reduction. Poincare’ maps are utilized to study the nonlinear localization and beat phenomena caused by the clearance connecting the coupled rods.
The Dynamics of a Flexible Levitated Droplet
Authors: Dupac Mihai , Marghitu Dan B. , Beale David G. 
Published: November 2020

Abstract
In this paper, a nonlinear dynamics analysis of the simulated data was considered to study the time evolution of an electro-magnetically levitated flexible droplet. The main goals of this work are to study the behavior of the levitated droplet and to investigate its stability. Quantities characterizing time series data such as attractor dimension or largest Lyapunov exponent were computed.
Topological Solitons in Non-Degenerate One-Component Chains: Part II — Numerical Study
Authors: Manevitch Leonid I. , Savin Alexander V. , Sigalov Grigori M. 
Published: November 2020

Abstract
In this paper, which is a direct continuation of part I, a numerical study of existence and stability of topological solitons revealed in part I is performed using smoothened potentials.
Symbolic Stability Boundaries and Root Locus Plots in Time-Periodic Systems
Authors: Butcher Eric A. 
Published: November 2020

Abstract
The recent development of a symbolic computational algorithm for approximating the parameter-dependent fundamental solution matrix of linear time-periodic systems is used to symbolically compute stability boundaries as an explicit function of the system parameters and to construct root locus plots. By evaluating this matrix at the end of the principal period, the parameter-dependent Floquet Transition Matrix (FTM), or the linear part of the Poincaré map, is obtained. The sub sequent use of well-known criteria enables one to obtain the equations for the stability boundaries in the parameter space as polynomials of the system parameters. The symbolic nature of the method also allows one to obtain root locus plots in the complex plane as a function of the system parameters. The roots of the FTM (Floquet multipliers) must lie within the unit circle for stability. Further, the technique can successfully be applied to periodic systems whose internal excitation is strong. The symbolic software Mathematica is used here to perform all symbolic calculations. Two illustrative example problems, viz., a parametrically excited simple pendulum and a double inverted pendulum subjected to a periodic follower force, are included.
Discontinuous Bifurcations in Stick-Slip Mechanical Systems
Authors: Galvanetto Ugo 
Published: November 2020

Abstract
Non-smooth dynamical systems exhibit continuous and discontinuous bifurcations. Continuous bifurcations are well understood and described in many textbooks, whereas discontinuous bifurcations are still the object of active research. Grazing bifurcations, C-bifurcations and other types of bifurcations characterised by jumps of the relevant Floquet multipliers have been described in the scientific literature. This paper deals with two discontinuous bifurcations found in mechanical systems affected by dry friction.
Computational Methods for Nonsmooth Acoustic Systems Arising in an Electromagnetic Hysteresis Identification Problem
Authors: Banks H. T. , Raye J. K. 
Published: November 2020

Abstract
Electromagnetic interrogation techniques have numerous useful applications, including locating mines or bunkers beneath the ground, and detecting abnormal tissue noninvasively within the body. Several recent successful such techniques involve using some type of interface, such as a superconductive metal backing or a standing acoustic wave grating, to reflect an oncoming electromagnetic wave. These electromagnetic wave reflections are then used to identify dielectric properties (conductivity and polarization) of the target materials. Many useful polarization models (for example, Debye, Lorentz, and higher order models) result in a hysteretic term in Maxwell’s equations. Thus, a wide class of electromagnetic interrogation problems involve identification of hysteresis mechanisms. We wish to examine a technique in which an acoustic wave traveling toward the oncoming electromagnetic wave acts as a virtual interface. As a first step in assessing this interrogation technique, we consider the equations describing an acoustic pressure wave produced by a windowed sine wave pulse traveling through a layered medium and develop computational methods for solving these equations. After considering several other approaches, we suggest that an adequate way to solve this system with the finite element method is to use a fully Galerkin scheme in a nonstandard weak formulation. Our approximation methods, resulting in large algebraic systems, are explained and computational findings are presented which support the efficacy of the approach.
Narrowband Control Design for Smart Structural Systems
Authors: Kolepp Daniel J. , Smith Ralph C. 
Published: November 2020

Abstract
This investigation focuses on the development of narrowband control strategies which are effective for structural systems subjected to both harmonic exogenous forces and stochastic uncertainties in the model or measurements. A cantilever beam with surface-mounted piezoceramic actuators is used as a prototypical structure since it exhibits physical attributes of a variety of vibrating structures but is sufficiently simple to facilitate initial control design. A PDE model for the structure is discretized using a spline-based Galerkin technique to obtain a semi-discrete system that is appropriate for finite-dimensional control design. A narrowband control method, which can be tuned to attenuate either natural frequencies or specific frequencies in the exogenous input, is developed and compared with standard LQR techniques through numerical examples.
Acoustic Control Modeling of Conical Bores With Actuating Boundary Conditions
Authors: Farinholt Kevin M. , Leo Donald J. 
Published: November 2020

Abstract
An investigation of the natural frequencies and mode shapes associated with sealed conical bores having actuating boundary conditions is presented. Beginning with the one dimensional wave equation for spherically expanding waves, modal characteristics are developed as functions of cone geometry and actuator parameters. This paper presents both analytical and experimental comparisons for the purpose of validating model and development techniques. An investigation of the orthogonality and adjointness of the solution is presented. A discussion of incorporating driving forces in the system model for the purpose of coupling control actuators with internal acoustics is also included. Including these driving forces, a state space model of the system is developed for the purpose of applying modern feedback control. This paper concludes with a study on applying Linear Quadratic Regulator techniques to this system, relating tradeoffs between spatially averaged pressure and control voltages. The results of our simulations indicate that pressure reductions of 30% are attainable with average control voltages of 14.4 volts, given an example geometry.
Adaptive Feedforward Active Noise Control in an Acoustic Duct
Authors: Ohadi A. R. , Esmailzadeh E. , Alasty A. 
Published: November 2020

Abstract
The single-reference/multi-output active noise control (ANC) of an accurate physical model of an acoustic duct system has been investigated. Computer model of a multi-channel ANC system with tonal and sweep sine input signals, and an adaptive feedforward algorithm that minimizes the generic cost function are developed. Results obtained for various single-input/single-output (SISO) configurations of ANC systems were compared. The dynamic response of a single-reference/multi-output ANC system, using Minimax and MEFXLMS algorithms, is studied and the effect of acoustical feedback neutralization in a multichannel ANC system is studied. Simulation results demonstrate that the multi-channel adaptive feedforward ANC system, using the Minimax algorithm, has a superior performance in comparison to the same system with MEFXLMS.
Optimization of a Resonant Bimorph Actuator Drive
Authors: Mockensturm Eric M. , Koopmann Gary H. , Frank Jeremy , Lesieutre George A. 
Published: November 2020

Abstract
A rotary actuator driven by piezoelectric bimorphs has been developed for various smart structure applications. A rotary (roller) clutch rectifies bimorph oscillation into rotational motion to convert electrical to mechanical power. While prototype actuators perform well, they were designed with just engineering intuition. Here, a mathematical model of the actuator is developed. Using empirical data collected from a prototype actuator and a roller clutch, the mathematical model was tuned so that it predicted accurately the performance of the prototype. The model was then used to optimize the design of the actuator. The model predicts that performance can be significantly increased by making slight modifications to the prototype. Work to verify these predictions of the mathematical model is underway.
High Dynamic Range Colocated Sensoriactuator for Control of High-Speed Optical Systems
Authors: Knowles Gareth , Bower Bruce 
Published: November 2020

Abstract
Vibratory load transmission reduction for precision space A major challenge to the aerospace industry is to develop precision beam steering optics with clear aperture as large as 8 inches that operate at bandwidths of 1KHz, have throws of 3–10 mrad, and position accuracy of 100 nrad. The proposed technology promises to meet these requirements by introducing a new piezoelectronically driven colocated sensoriactuation system. The novel sensor promises to enable ultra-linear, 1nm resolution and 4 KHz small signal bandwidth in a small package. The sensor is integrated into the actuation mechanism in order to provide advantageous colocated functioning. The actuation mechanism is of unique high stiffness and shear strength capable of driving at high-bandwidth with no low coupling modes present. The proposed technology offers a lower cost, lighter weight, lower volume solution that can markedly increase performance capability. The approach is applied to the problem of controlling fast optics for precision optical compensation or hyperspectral imaging. The paper presents aspects of design experiment and system measurement.
Model-Based Estimation of Impact Forces Affecting Elastic Structures: Simulation and Experiment
Authors: Abicht Claus , Bormann Jens , Müller Peter C. , Söffker Dirk , Ulbrich Heinz 
Published: November 2020

Abstract
The paper introduces into the concept of model-based impact estimation of elastic structures. Based on the model of the affected linear structure a robust linear observer technique is applied to estimate the unknown impacts. The complete procedure of impact estimation is shown by simulations. Results of the observer-based estimation of unknown impacts are presented. As a new result, it is observed that the proposed observer technique can generally (but with limitations) be applied to elastic structures.
A Simple Dynamic Modeling of Head Slap in Hard Disk Drive
Authors: Lee Seong-Hun , Lee Jeong-Hak , Kim Kwang-Joon 
Published: November 2020

Abstract
In order to understand mechanism of the impact between head and disk of a HDD subject to a shock and to improve the shock resistance effectively, it is essential to develop a dynamic model which can represent well the head slap. Although motion of the head and disk subject to a shock requires modeling by a continuous system to be rigorous, in this study, a simplified lumped parameter model is developed to understand basic dynamics of the head slap and to determine crucial parameters for the improvement of the structural design. In addition, drop test results of the HDD are presented to back to up the derived model.
A Mobile Mechanism With Slant Leg on a Vibratory Floor
Authors: Yamaguchi Hideya , Yashima Masahito 
Published: November 2020

Abstract
This paper investigates the characteristics of a mobile mechanism that consists of a main mass and a slant leg with a rotational spring at the joint. The device travels on an oscillating floor due to the difference in the friction force between forward and backward directions during the stick-slip motion. Numerical simulation and experimentation show that the direction and velocity of movement are controlled by the exciting frequency. Furthermore, the effects of the angle of the slant leg and the sliding coefficient of friction on those characteristics are investigated.
Distributed Friction and Microslip in Mechanical Joints With Varying Degrees-of-Freedom
Authors: Quinn D. Dane 
Published: November 2020

Abstract
This work considers the effect of distributed friction on the dynamics arising from a simple model for a jointed structure. A hierarchy of models is developed, parameterized by the degree-of-freedom n, which physically corresponds to the number of possible slip zones. When the resulting system is subjected to harmonic forcing, numerical simulations indicate that the instantaneous power dissipated by the frictional forces is sensitive to n. However, the frictional work per unit forcing cycle is, surprisingly, relatively insensitive to the degree-of-freedom, provided n is greater that some minimum number which depends on the amplitude of the external forcing as well as the maximum frictional force. Finally, representative simulations are shown as both the amplitude and frequency of the external forcing are varied. This model provides a starting point for the development of reduced-order models of structural interfaces.
Vibration Control of a Beam Using a Sliding Support
Authors: Nguyen Phillip H. , Ginsberg Jerry H. 
Published: November 2020

Abstract
This paper discusses a concept for controlling flexural vibration of a beam in which a pin support oscillates harmonically parallel to the beam’s axis. This induces a periodic fluctuation of the effective inertia and stiffness, which represents a source of parametric excitation. A model of the response is developed by using a Ritz series modified to allow the basis functions to be time, as well as position, dependent. Solutions are obtained by numerically integrating the equations of motion. Vibration control requires identification of the support frequency, amplitude, and phase angle that reduce the overall motion relative to what would be obtained if the support were stationary. It is shown that resonances can be controlled in this manner. However, the concept is shown to be ineffective for broadband vibration reduction because the parametric excitation merely shifts the resonant frequencies, while it also induces new resonances.
Input-Shaped Control of Gantry Cranes: Simulation and Curriculum Development
Authors: Forest Craig , Frakes David , Singhose William 
Published: November 2020

Abstract
Knowledge of vibrations and controls has increased significantly by utilizing emerging computer capabilities. Engineering education should embrace this technology through computer simulations that predict and display the dynamic response of interesting systems. For example, manipulating payloads with an overhead gantry crane can be challenging due to the oscillations induced by the crane motion. The problem gets increasingly difficult when the work environment is cluttered with obstacles. This paper describes a simple input shaping solution to the vibration problem and shows how this problem and concept were integrated into the curriculum of an undergraduate system dynamics and controls course at the Georgia Institute of Technology. Furthermore, an educational tool is used to gather data on how crane operators attempt to navigate around obstacles. The results show that input shaping reduces the likelihood of collisions between the payload and obstacles, while at the same time allowing operators to be more aggressive in selecting navigation paths.
Obstacle Avoidance for 2D Hyper-Redundant Manipulators Using Harmonic Potential Functions and the Mode Shape Technique
Authors: Fahimi F. , Ashrafiuon H. , Nataraj C. 
Published: November 2020

Abstract
Obstacle avoidance for discrete-link two-dimensional (2D) hyper-redundant manipulators in known environments is considered. The manipulator is divided into two sections, a proximal section that has not entered the space among obstacles and a distal section among the obstacles. Harmonic potential functions were used, in order to avoid local minima in cluttered environments. A modified panel method is used to generate the potential of any arbitrary shaped obstacle in two-dimensional space. An alternative backbone curve concept and an efficient fitting method are introduced to control the trajectory of proximal links. The fitting method is recursive and avoids the complications involved with solving large systems of nonlinear algebraic equations. Combination of the safe path derived from the harmonic potential field and the backbone curve concept leads to an elegant kinematic control strategy that guarantees obstacle avoidance for planar hyper-redundant robotic manipulators.
The Robust Adaptive Control of Free-Floating Space Manipulator Systems
Authors: Li Chen , Yanzhu Liu 
Published: November 2020

Abstract
In this paper, the kinematics and dynamics of free-floating space manipulator systems are analyzed, and it is shown that the Jacobian matrix and the dynamic equations of the system are nonlinearly dependent on inertial parameters. In order to overcome the above problems, the system is modeled as under-actuated robot system, and the idea of augmentation approach is adopted. It is demonstrate that the augmented generalized Jacobian matrix and the dynamic equations of the system can be linearly dependent on a group of inertial parameters. Based on the results, the robust adaptive control scheme for free-floating space manipulator with uncertain inertial parameters to track the desired trajectory in workspace is proposed, and a two-link planar space manipulator system is simulated to verify the proposed control scheme. The proposed control scheme is computationally simple, because we choose to make the controller robust to the uncertain inertial parameters rather than explicitly estimating them online. In particular, it require neither measuring the position, velocity and acceleration of the floating base with respect to the orbit nor controlling the position and attitude angle of the floating base.
Finite Element Analysis of Thermal Buckling and Postbuckling of Composite Plates With Embedded SMA
Authors: Weifang Zhong , Jing Zou , Yongdong Wu 
Published: November 2020

Abstract
Based on Von Karman strain-displacement relations and variational principles, the FEM formulations, which are used to analyze the thermal buckling, and thermal postbuckling of composite plates with embedded SMA are presented in this study. The recovery stress and young modulus are calculated by one-dimensional constitutive model. Some numerical examples are also presented. The results indicate that activated SMA can suppress the thermal buckling of the plates and reduce thermal postbuckling deflections.
An Experimental Approach to the Design of PVDF Modal Sensors
Authors: Cuhat Daniel , Davies Patricia 
Published: November 2020

Abstract
The principle of modal sensing is based on the use of a shaped PVDF piezoelectric film measuring strains on the surface of a bending beam and acting as a modal filter. So far, the use of this type of sensors has remained confined to studies involving uniform structures with classical boundary conditions. The goal of this paper is to present an experimental methodology for the design of a shaped modal sensor applicable to an non-uniform Euler-Bernoulli beam with arbitrary boundary conditions. This approach is illustrated with test data collected on a cantilever beam structure with a laser Doppler velocimeter.