bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Identification of Hysteretic Systems Using the Differential Evolution Algorithm
Authors: Kyprianou A. , Worden K. , Panet M. 
Published: February 2021

Abstract
Hysteretic or memory dependent phenomena are observed in many areas such as magnetism, electricity, materials’ phase transitions and elasto-plasticity of solids [1]. In mechanical vibrations, the elasto-plasticity of some vibrating components introduces non-linearities which can be identified as of hysteretic type. A model, which describes accurately many random non-linear vibrations of the above type, is the Bouc-Wen model. This model is shown in equation (2) below in the context of the forced one-degree of freedom oscillator: (1)mx¨+cx˙+kx+z=f(t) where m, c and k are the mass, damping and spring coefficients respectevely. The restoring force z is given by the Bouc-Wen model (2): (2)z˙=−a|x˙|zn−β|zn|x˙+Ax˙ n oddz˙=−a|x˙|zn−1|z|−βx˙zn+Ax˙ n even The model was firstly introduced by Bouc in its rudimentary form with n equal to unity [2]. This was able to describe the hysteresis loop peculiar to the relationship between the restoring force z and displacement x. The paramaters α and β govern the shape of the loop. Wen generalised the Bouc equation to its final form by introducing the parameter n as given in 2 [3]. This parameter controls the smoothness of the hysteresis loop. The parameter A contributes to the linear striffness of the oscillator.
Because of the versatility of this model to represent various shapes of hysteresis loops, it has attracted many applications in the area of hysteretic vibrations. As a consequence the model is studied for various parameter sets in order to fit in different applications. Therefore a need emerges to identify the parameters for each different case.
This paper presents results of experimental identification of the Bouc-Wen model for an experimental oscillator. The parameters are estimated using the differential evolution method. The authors reported results for simulated data using this method in a previous paper [4].
Response of Hysteretic Multidegree-of-Freedom Systems Using Harmonic Balance Method
Authors: Capecchi Danilo , Masiani Renato , Vestroni Fabrizio 
Published: February 2021

Abstract
This article illustrates the nonlinear response of a hysteretic two degree of freedom system. The constitutive laws which define the force-displacement relation are based on a hysteretic model with Masing rules linked to a suitable nonlinear elastic model. Attention is focused on the periodic response, though an insight is also given to the non-periodic response. The method of analysis used is the harmonic balance with many components. Frequency-response curves are evaluated for different system characteristics. Ratios of small amplitude vibration frequency 3 and 2 are considered, with different hysteresis degree. Notwithstanding the dissipation due to hysteresis usually destroys most of the phenomena evidenced by the classical nonlinear oscillators, in the present analysis a rich behavior is found: IT symmetric and non symmetric, 2T periodic responses are found and so on.
Visualization of the A0 Lamb Wave and a Scholte-Stoneley Wave Interaction
Authors: Latard V. , Merlen A. , Pernod P. , Ahyi A. 
Published: February 2021

Abstract
Previous studies have shown the efficiency of the experimental impulsive acoustic approach for a fine understanding of acoustic scattering processes. The association of a high speed shadowgraph system and a spark generated acoustic pulse allowed the first visualization of the radiation into a fluid of a A0 Lamb wave travelling along an elastic plate (Ahyi and al., 1998) or the interaction of the A (Scholte Stoneley) and A0 on more complex geometries (Latard, 1998). Moreover it allows to follow the evolution in time and determine the generation points of the waves. It is shown in this paper that this visualization technique of impulsive scattering is a quantitative method providing not only wave velocities or frequencies, but also dispersion curves thanks to a single view of the phenomena. This paper presents also the visualization of the A wave by its interaction with the A0 radiation. Numerical simulations of this interaction are compared successfully with visualizations.
Influence of Mechanical Architecture and Coupling Effects on the Vibratory Behavior of Complex Gear Transmissions
Authors: Bourdon Adeline , Yakhou Karim , Chaloyard Laurent , Play Daniel 
Published: February 2021

Abstract
This paper describes a dynamic model for gear transmissions acting around a static working point, and taking into account the complete mechanical components. Gearbox casing behavior is introduced by using substructure analysis, and a tangent stiffness matrix is defined for each roller body bearing element. This model is used to compare the pullup and pulldown dynamic behavior of a five speed medium size automobile gearbox where the gear meshing phenomena are assumed to be identical. The eigenmodes of the pullup and pulldown models are compared and frequency responses to meshing excitation are studied. Substantial differences between pullup and pulldown behavior are observed and associated with to the orientation of static load.
Analysis of the Forces Between Gear Teeth by the Photoelasticity Method
Authors: Podzharov Evgueni I. , Villela Gonzalez Victor R. 
Published: February 2021

Abstract
The photoelasticity method was used to study the change of forces during the gear engagements. The cinetostatic analysis forecasts a change of normal force between teeth when the point of contact passes the pitch point. This happens because of the action of friction forces between teeth when the torques on the gear wheels are constants. To prove this measurements of forces between teeth by the photoelacticity method were implemented in a test bench with a gear test rig with closed mechanical circuit.
Spectral Element Modeling of the Power Flow in a T-Beam Structure: A Computational Experiment
Authors: Ahmida Khaled M. , Arruda José Roberto F. 
Published: February 2021

Abstract
An alternative approach is proposed to predict the power flow pattern and the power dissipated in a T-beam structure. The T-beam used is the same chosen by Burroughs et al. (1994) as part of a round-robin study on structure-borne sound analysis. The Spectral Element Method, which is formulated directly in the frequency domain, is used to predict the energy distribution in the beam. The structure is also modeled using Statistical Energy and Finite Element Analyses. The results obtained by these three approaches are compared to previous FEA results obtained by Hambric (1995). The SEM and FEA results are shown to match well at lower frequencies. The spectral element analysis is shown to be more accurate in predicting the power flow at higher frequencies.
Friction-Induced Vibration in a Dynamometer Utilizing a Two-Disk Friction Interaction
Authors: Anabtawi Ahmed , Farhang Kambiz 
Published: February 2021

Abstract
A mathematical model is developed for a dynamometer for testing a two-disk friction brake system. The model accounts for the compressive shear properties of the friction disks as well as stiffness and inertial characteristics of the dynamometer. Friction coefficient/velocity relations are established using the measurement data and employed in the mathematical model to perform simulations of the dynamometer’s vibration response and instability.
Five different simulations are performed. The first four employ a fifth order polynomial fit from the coefficient friction measured experimentally. One of these four simulations uses data from noisy test while the other three utilize relatively low-noise tests. The fifth and last simulation is carried out using a theoretical coefficient of friction, being assumed to experience certain sinusoidal variation. Such function is used to study the effect of variability in kinetic coefficient of friction of the experimental data.
In the first four simulations (i.e. the experimental cases), it is observed that the simulations turn unstable when the friction-velocity slope becomes negative. That phenomenon is alleviated when higher damping is used. In the fifth simulation (i.e. the sinusoidal case), variation in the coefficient of friction is found to increase vibration in the dynamometer system.
Brake Squeal Analysis by Finite Elements and Comparisons to Dyno Results
Authors: Nack W. V. 
Published: February 2021

Abstract
An approximate analysis method for brake squeal is presented. Using MSC/NASTRAN a geometric nonlinear solution is run using a friction stiffness matrix to model the contact between the pad and rotor. The friction coefficient can be pressure dependent. Next, linearized complex modes are found where the interface is set in a slip condition. Since the entire interface is set sliding, it produces the maximum friction work possible during the vibration. It is a conservative measure for stability evaluation. An averaged friction coefficient is measured and used during squeal. Dynamically unstable modes are found during squeal. They are due to friction coupling of neighboring modes. When these modes are decoupled, they are stabilized and squeal is eliminated. Good correlation with experimental results is shown. It will be shown that the complex modes baseline solution is insensitive to the type of variations in pressure and velocity that occur in a test schedule. This is due to the conservative nature of the approximation. Convective mass effects have not been included.
Studies on the Dynamic Behavior of a Printed Circuit Board
Authors: Wang Hongfang , Zhao Mei 
Published: February 2021

Abstract
The dynamic behavior of printed circuit (PC) boards exercises strong influence on the reliability of electronic equipment. In this paper, the dynamic behavior of a PC board is studied by means of computation and verified by experiment with results compared favorably. This shows that FE modeling strategy used is sound. In general, excitement frequencies induced by external environment are in the range from several Hz to several hundred Hz. In order to avoid product failures due to resonance, it is desirable to make the fundamental natural frequency of PC boards as high as possible. Two structural modified design methods to raise the fundamental frequency are given with a numerical example.
Thickness Profiles for Rotating Circular Disks That Maximize Critical Speed
Authors: Renshaw Anthony A. , Warner Grant M. 
Published: February 2021

Abstract
Thickness profiles for rotating disks that maximize critical speed are determined for use by designers of industrial circular saws. The disk thickness is permitted to vary between fixed lower and upper bounds, the lower bound corresponding to the minimum thickness saw capable of supporting the in-plane stresses associated with cutting forces and rotation, the upper bound corresponding to the thickness of the saw teeth. The optimal thickness profile consists of two annuli, the inner one with thickness equal to the upper bound, the outer one with thickness equal to the lower bound. With the optimal thickness profile, the critical speed can be raised up to 24%, depending on the clamping ratio of the disk and the lower bound. Optimal thickness profiles and increases in critical speeds are described and compared to existing saw designs.
The Influence of Transverse Clamping Flexibility on Centrally Clamped, Centripetally Tensioned, Rotating Circular Disks
Authors: Kim Hong-Ryul , Renshaw Anthony A. 
Published: February 2021

Abstract
A detailed design study is presented analyzing the influence of transverse clamping flexibility on the critical speeds and transverse stiffness of centrally clamped, centripetally tensioned, rotating circular disks. Tensioning techniques, which introduce in-plane stresses into thin plates, are commonly used to improve the critical speed and transverse stiffness of industrial circular saws. In centripetal tensioning, the magnitude of tensioning increases with the rotation speed of the disk, an objective that requires the disk to expand radially within the clamp as it rotates. Clamp designs that allow this radial expansion are necessarily more flexible in the transverse direction than traditional clamps, an effect that can be detrimental to the performance of high speed circular saws. The analysis here provides quantitative design guidelines for centripetal tensioning clamps to ensure that they improve circular saw performance.
Nonlinear Vibration of Parametrically Excited Viscoelastic Moving Belts
Authors: Zhang Lixin , Zu Jean W. 
Published: February 2021

Abstract
The dynamic response and stability of parametrically excited viscoelastic belts are investigated in this paper. The linear viscoelastic differential constitutive law is employed to characterize the material property of belts. The generalized equation of motion is obtained for a viscoelastic moving belt with geometric nonlinearity. The method of multiple scales is applied directly to the governing equation, which is in the form of continuous gyroscopic systems. Closed-form expressions for the amplitude, existence conditions and stability conditions of non-trivial limit cycles of the summation resonance are obtained. Effects of viscoelastic parameters, excitation frequencies, excitation amplitudes and axial moving speeds on stability boundaries are discussed.
Combinations for the Free Vibration Behaviors of Anisotropic Rectangular Plates Under General Edge Conditions
Authors: Narita Yoshihiro 
Published: February 2021

Abstract
The free vibration behavior of rectangular plates provides important technical information in structural design, and the natural frequencies are primarily affected by the boundary conditions as well as aspect and thickness ratios. One of the three classical edge conditions, i.e., free, simple supported and clamped edges, may be used to model the constraint along an edge of the rectangle. Along the entire boundary with four edges, there exist a wide variety of combinations in the edge conditions, each yielding different natural frequencies and mode shapes. For counting the total number of possible combinations, the present paper introduces the Polya counting theory in combinatorial mathematics, and formulas are derived for counting the exact numbers. A modified Ritz method is then developed to calculate natural frequencies of anisotropic rectangular plates under any combination of the three edge conditions and is used to numerically verify the numbers. In numerical experiments, the number of combinations in the free vibration behaviors is determined for some plate models by using the derived formulas, and are corroborated by counting the numbers of different sets of the natural frequencies that are obtained from the Ritz method.
A Closed-Form Approach to Transient Dynamic Response of One-Dimensional Distributed Systems
Authors: Wu Xuqiang , Yang Bingen 
Published: February 2021

Abstract
A closed-form transient analysis of one-dimensional distributed dynamic systems is presented. The proposed approach, called the Z-Prime Method, starts with inverse Laplace transform of a distributed transfer function formulation. Through establishment of a relation between transfer function residues and system eigensolutions, the closed-form transient response of the distributed system under general external, boundary and initial disturbances is obtained. Unlike conventional modal expansion, the proposed method does not depends on any orthogonal eigenfunctions.
Modal Analysis for the Active Multi-Layer Beams by Using Spectrally Formulated Exact Eigenfunctions
Authors: Lee Usik , Kim Joohong 
Published: February 2021

Abstract
In this paper, a modal analysis method (MAM) is introduced for the active multi-layer laminate beams. Two types of active multi-layer laminate beams are considered: the elastic-viscoelastic-piezoelectric three-layer beams and the elastic-piezoelectric two-layer beams. The dynamics of the multi-layer laminate beams are represented by a set of fully coupled equations of motion, derived by using Hamilton’s principle. The exact eigenfunctions are spectrally formulated and the orthogonality of eigenfunctions is derived in a closed form. The present MAM is evaluated through some numerical examples. It is shown that the dynamic characteristics obtained by the present MAM certainly converge to the exact ones obtained by SEM as the number of eigenfunctions superposed in MAM is increased. The modal analysis results are also compared with the results obtained by FEM.
Forced Vibration and Dynamic Stability of a Rotating Tapered Composite Timoshenko Shaft
Authors: Kim Wonsuk , Argento Alan , Scott Richard A. 
Published: February 2021

Abstract
The response and stability of a high speed extended length tool holder subjected to cutting forces typical of milling operations are studied. The system is modeled as a rotating, tapered, filament-wound composite. Timoshenko shaft having clamped-free supports, and subjected to fluctuating, deflection-dependent, cutting-type end loads. Viscous damping is also included in the model. The general Galerkin method is used to satisfy spatial dependence in the system equations, and the monodromy matrix method and numerical integration are used to determine the system’s stability and response, respectively.
Analysis of the Natural Vibration Properties of a Timoshenko Beam Supported by Springs (by Finite Integral Transform Method)
Authors: Xu Zhixiang , Tamura Hideyuki , Seto Kunisato 
Published: February 2021

Abstract
This paper presents analytical results of transverse vibration of a Timoshenko beam supported by spring-spring which stiffness is variable, that is a simplified model of magnetically levitated vehicle body’s vibration problem and magnetic bearings support shaft’s vibration problem. By applying the finite integral transform technique, the analytical solution of this dynamic model is successfully obtained. Especially, by investigating the frequency equation, the effect of the stiffness of two supporting-springs to the natural frequencies is clarified. From the results, it is cleared that the natural frequencies of the beam system can be effectively controlled by changing the supporting-spring’s stiffness.
Free Response of Twisted Plates
Authors: Mockensturm Eric M. , Mote C. D. 
Published: February 2021

Abstract
In previous work, Mockensturm and Mote (1999) investigated the effects of twist on steady motions of an axially moving plate. It was found that twisting produces compressive stresses that increase with twist, aspect ratio, and initial, longitudinal tension. In this work, we study the effects of the stresses and non-flat equilibrium produced by twist on the free response. To accomplish this, the equations of motion are linearized about the equilibrium configuration, yielding a set of three, coupled, linear partial differential equations. The equations are discretized and the free response is predicted from the resulting discrete eigenvalue problem. As a function of twist angle, the natural frequencies first increase and then decrease rapidly to zero as the compressive lateral stresses become sufficiently large to cause wrinkling. The effects of thickness, aspect ratio, and initial tension on natural frequencies are also studied.
Nonlinear Dynamics of a Taut Spatial String With Material Nonlinearities
Authors: Leamy Michael J. , Gottlieb Oded 
Published: February 2021

Abstract
A spatial string model incorporating a nonlinear (and non-conservative) material law is proposed using finite deformation continuum mechanics. The influence of material nonlinearities on the string’s dynamic response to excitation near a transverse natural frequency is shown to be small due to their appearance at high orders only. Material nonlinearities appear at low order in the equations for excitation near a longitudinal natural frequency and a solution for this case is developed by applying the method of multiple scales directly to the partial differential equations. An example string is considered to explore the influence of material nonlinearities on the dynamic response. Rich modal content is found, which can not be predicted by simpler models. Additionally, the material nonlinearities are shown to exert their greatest, influence away from resonance, where they serve to limit the response amplitudes.
Modal Overlap and Dissipation Effects in a Fuzzy Structure Containing a Continuous Master Element
Authors: Drexel M. V. , Ginsberg J. H. 
Published: February 2021

Abstract
This work was prompted by a study performed by Strasberg (1997) in which numerous small spring-mass-damper systems are attached to a large suspended mass representing the master structure. The isolated natural frequency of each attached system was selected to match in average the natural frequency of the isolated master structure. Strasberg found that the critical issue when an impulse excitation is applied to the master structure is the bandwidth of the isolated attached systems in comparison to the spacing between the natural frequencies of the system. Modal overlap, which corresponds to the bandwidths that exceed the spacing of those frequencies, was shown to greatly influence the response of the master structure. Light damping, for which there is little modal overlap, corresponds to an impulse response that consists of a sequence of nearly periodic exponentially decaying pulses, and the transfer function for harmonic excitation of the master structure indicates that the sub-structure acts as a vibration absorber for the master structure. Increased damping leads to modal overlap, with the result that the impulse response consists of a single decaying pulse. The frequency domain transfer function indicates that the vibration absorber effect is enhanced. The present work explores these issues for continuous systems by replacing the one degree of freedom master structure with a cantilever beam. The system parameters are selected to match Strasberg’s model, with the suspended sub-structure placed randomly along the beam. The beam displacement is represented as a Ritz series whose basis functions are the cantilever beam modes. The coupled equations are solved by a state-space eigenmode analysis that yields a closed form representation of the response in terms of the complex eigenmode properties. The continuous fuzzy structure is shown not to display the transfer of energy between the master structure and the substructure that was exhibited by the discrete fuzzy structure, apparently because of the asynchronous motion of the attachment points resulting from the spatial variability of the beam’s motion. The vibration absorber effect for harmonic excitation is only obtained for the heavy damping in the case of a beam.