bluuebunny/crossref_metadata_2025_split huggingface dataset:
Steady-State Non-Synchronous and Localized Responses of Tuned Pendulum Vibration Absorbers
Authors: Al-suwaiyan Abdallah S. , Shaw Steven W. 
Published: February 2021

Abstract
Previous analytical studies of Centrifugal Pendulum Vibration Absorber (CPVA) systems have focused on the dynamics of either a single absorber mass or multiple absorber masses moving along very special paths. In this paper, an approach is taken that allows one to investigate the dynamics of multi-absorber systems that have quite general paths for the absorber masses, including those used in practice. Of particular interest here are the existence and stability of certain classes of non-unison responses, including those in which the amplitude of a sub-group of absorbers is larger than the expected unison response. It is shown via the method of averaging that these steady state responses may exist and be stable for certain types of paths, including the commonly-used mistuned circular path. Furthermore, it is shown that these responses can co-exist with a stable unison response, even for very small torque levels. The analytical results are compared with numerical simulations and good agreement is found.
Nonlinear Dynamics of Orthogonal Metal Cutting: Experimental Studies
Authors: Foong Chee-Hoe , Wiercigroch Marian , Deans William F. 
Published: February 2021

Abstract
The elimination of chatter is one of the major aims in machining to improve geometrical accuracy and surface finish. In this study, occurrence of chatter was investigated experimentally using a specially designed rig by examining time histories of the cutting and thrust force components. A broad experimental study was conducted using brass, cast iron and aluminium samples. It was found that by changing the horizontal stiffness of the rig, the thrust force variations (in the vertical direction) were completely eliminated for the cast iron samples. A systematic analysis of the chip formation for the aluminium alloy is presented.
Computer Based Model of Vibro-Impact Driving
Authors: Lok Howe Ping , Neilson Richard D. , Rodger Albert A. 
Published: February 2021

Abstract
A computer based model of a novel vibro-impact ground moling system is presented as an aid to designing such systems. The equations of motion governing the system are presented and a corresponding laboratory model is described. The model includes elasto-plastic modelling of the end resistance and Coulomb terms for side resistance between the soil and the body of the moling system. Results for both penetration time histories and end resistance time histories from both the model and the rig are presented which show that the model can adequately predict the motion of the mole for design purposes.
Estimation of the Largest Lyapunov Exponent of Discontinuous Systems Using Chaos Synchronization
Authors: Stefanski Andrzej , Wojewoda Jerzy , Kapitaniak Tomasz , Brindley John 
Published: February 2021

Abstract
Properties of chaos synchronization have been used for estimation of the largest Lyapunov exponent of a discontinuous mechanical system. A method for such estimation is proposed and an example is shown, based on coupling of two identical systems with dry friction which is modelled according to the Popp-Stelter formula.
Nonlinear Dynamics in the Estimation of Rotor-Bearing Dynamic Properties in Large Hydro-Units*
Authors: Zhang X. Z. , Liu B. G. 
Published: February 2021

Abstract
This paper describes a method with which the nonlinear dynamic response and the natural features of rotor-bearing systems in large hydro-units can be estimated on a personal computer. The key step of this process is to estimate the dynamic eccentricity of the journal center in every guide bearing when the system is subjected to dynamic loads. As an example, the nonlinear dynamic responses, the natural frequencies and the critical speeds of the rotor-bearing system of a 240MW hydro-unit are calculated. The calculated dynamic responses agree well with the ones measured in the field.
On the Torus Flow Y′ = A + B cos Y + C cos X and its Relation to the Quasiperiodic Mathieu Equation
Authors: Mason Stephanie , Rand Richard 
Published: February 2021

Abstract
We obtain power series solutions to the “abc equation” dydx=a+bcosy+ccosx, valid for small c, and for small b. This equation is shown to determine the stability of the quasiperiodic Mathieu equation, z¨+(δ+ϵA1cost+ϵA2cosωt)z=0, in the small ϵ limit. Perturbation results of the abc equation are shown to compare favorably to numerical integration of the quasiperiodic Mathieu equation.
Multiple Time Scale Analysis for Bifurcation From a Double-Zero Eigenvalue
Authors: Luongo Angelo , Paolone Achille , Di Egidio Angelo 
Published: February 2021

Abstract
The multiple scale method is applied to analyze bifurcations from a double zero eigenvalue of general multiparameter dynamical systems. Due to the coalescence of the eigenvalues, the Jacobian matrix at the bifurcation is nilpotent. This entails using time scales with fractional powers of the perturbation parameter. The reconstitution method is employed lo obtain a second-order o.d.e. in the unique unknown amplitude. It coincides with Bogdanova-Arnold’s normal form for the bifurcation equation. Referring to an example, the present approach and the classical center manifold plus normal form method are compared. Finally, the mechanical behavior of a non-conservative two d.o.f. system is studied.
Effect of Coulomb Damping on Buckling of a Simply Supported Beam
Authors: Yabuno H. , Oowada R. , Aoshima N. 
Published: February 2021

Abstract
The present work describes a significant influence of a slight Coulomb damping on buckling of the simply supported beam subjected to an axial compressive force. Coulomb damping in the supporting points produces equilibrium regions around the well-known stable and unstable steady states under the pitchfork bifurcation which are analytically obtained in no consideration of the effect of Coulomb damping. After the transient response, the beam can stop any states in the equilibrium region, which becomes wider in the vicinity of the bifurcation point, depending on the initial condition. Also, the imperfection due to gravity is considered and it is theoretically shown that the equilibrium region is connected in the case when the imperfection due to gravity is relatively small comparing with the effect of the Coulomb damping, while the steady states under the pitchfork bifurcation in no consideration of the effect of Coulomb damping are necessarily disconnected by imperfection. Experimental results confirm the theoretically predicted effect of Coulomb damping in the supporting point on the buckling behavior of the beam.
Dynamics and Stability of Partial Immersion Milling Operations
Authors: Zhao M. X. , Balachandran B. , Davies M. A. , Pratt J. R. 
Published: February 2021

Abstract
In this paper, numerical and experimental investigations conducted into the dynamics and stability of partial immersion milling operations are presented. A mechanics based model is used for simulations of a wide range of milling operations and instabilities that arise due to regeneration and/or impact effects are studied. Poincaré sections are used to assess the stability of motions. The studies reveal that apart from Hopf bifurcation of a periodic motion, a period-doubling bifurcation of a periodic motion may also lead to chatter in partial immersion milling operations. Issues such as tooth contact time variation and structure of stability charts are also discussed.
Experimental and Analytical Investigation of the Subcritical Instability in Metal Cutting
Authors: Kalmár-Nagy Tamás , Pratt Jon R. , Davies Matthew A. , Kennedy Michael D. 
Published: February 2021

Abstract
A single-degree-of-freedom dynamic cutting fixture is used to map out a part of the lobed stability boundary in a simple high-speed machining experiment. The experiment reveals the hysteretic nature of the instability. A 1 DOF mechanical model is derived using parameters identified from the experiment. We then show the existence of a subcritical Hopf bifurcation in this delay-differential equation model which corresponds to the observed experimental instability. The calculation is based on center manifold reduction. Then time domain simulation is used to solve the full nonlinear equation of motion that allows for the tool to leave the workpiece giving excellent agreement with the experiment.
Suppression of Parametric Resonance of a Cantilever Beam by a Pendulum-Type Vibration Absorber
Authors: Yabuno Hiroshi , Kawazoe Jun , Aoshima Nobuharu 
Published: February 2021

Abstract
The dynamic response of a parametically excited cantilever beam with a pendulum-type vibration absorber is presented. The equation of motion and the associated boundary conditions are derived considering the static friction for the rotating motion at the pivot of the pendulum. It is thoretically shown that the static friction plays a dominant role in the suppression of the parametric resonance. The boundary conditions are different between the cases when the motion of the pendulum is locked by the static friction and when it’s not. According to this variation of the boundary conditions depending on the pendulum motion, the natural frequencies of the system are automatically changed and the unstable regions for the parametric resonance are also shifted, so that the parametric resonace does not occur. Furthermore experimental results verify the effectiveness of the pendulum as a vibration absorber for the parametric resonance.
Nonlinear Transient Localization and Low Dimensional Models of a Flexible System With a Clearance
Authors: Ma Xianghong , Vakakis Alexander F. 
Published: February 2021

Abstract
Transient nonlinear localization in a system of two rods coupled with a nonlinear backlash spring is studied in this work. The method of Karhunen-Loeve (K-L) decomposition is then used to reduce the order of the dynamics, and to study nonlinear effects by considering energy transfers between leading K-L modes. In addition, 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. Reconstructions of transient nonlinear responses using these low dimensional models reveals the accuracy of the order reduction.
Comparison of Two Rate-Independent Hysteresis Models With Application to Piezoceramic Transducers
Authors: Royston Thomas J. , Lee Soon-Hong , Friedman Gary 
Published: February 2021

Abstract
The applicability of and relationship between two rate-independent hysteresis models that have been used to describe hysteresis in piezoceramic transducers are investigated. It is shown that the generalized Maxwell resistive capacitor hysteresis model is a particular case of the classical Preisach hysteresis model. The Preisach function that reduces the Preisach model to the Maxwell resistive capacitor model is derived. It is also shown that the inverse of the Maxwell model is this same particular case of the classical Preisach model. A Maxwell model identification procedure based on Preisach identification principles is formulated. The applicability of the classical Preisach and Maxwell hysteresis models for identifying and simulating piezoceramic dielectric behavior is investigated experimentally via studies on a 1-3 piezoceramic composite. Results indicate that both hysteresis models can accurately represent piezoceramic hysteresis. It is noted that the identified relationship between Preisach and Maxwell hysteresis models may prove useful in a wider range of hysteresis applications than just those involving piezoceramics.
Random Vibration Studies of a SDOF System With Shape Memory Restoring Force
Authors: Duval Luis , Noori Mohammad N. , Hou Zhikun , Davoodi Hamid , Seleecke Stefan 
Published: February 2021

Abstract
Intelligent and adaptive material systems and structures have become very important in engineering applications. The basic characteristic of these systems is the ability to adapt to the environmental conditions. One of the new class of materials with promising applications in structural and mechanical systems are Shape Memory Alloys (SMA). The mechanical behavior of shape memory alloys in particular shows a strong dependence on temperature. This property provides opportunities for the utilization of SMAs in actuators or energy dissipation devices. However, the behavior of systems containing shape memory components under random excitation has not yet been addressed in the literature. Such study is important to verify the feasibility of using SMAs in structural systems. In this work a non-deterministic study of the dynamic behavior of a single degree-of-freedom (SDOF) mechanical system, having a Nitinol spring as a restoring force element is presented. The SMA spring is characterized using a one-dimensional phenomenological constitutive model based on the classical Devonshire theory. Response statistics for zero mean random vibration of the SDOF under a wide range of temperature is obtained. Furthermore, nonzero mean analysis of these systems is carried out.
Ideal Elastic-Plastic Oscillators Subjected to Stochastic Input
Authors: Caddemi S. , Di Paola M. 
Published: February 2021

Abstract
The paper deals with the evaluation of the probabilistic response of an ideal elastic-plastic single degree of freedom oscillator subjected to a normal white noise. The analysis has been conducted on the hypothesis that accumulated plastic displacements are a compound homogeneous Poisson process independent of the external excitation. In this case plastic displacements can be treated as an additional external noise, to be identified, acting on a linear system.
In the paper a time domain approach to obtain the two variable non stationary correlation function is proposed. Hence the evolutionary power spectral density function is also obtained.
A numerical example is presented in order to show the accuracy of the presented procedure in comparison to Monte Carlo simulations.
Poincaré Map-Based Continuation of Periodic Orbits in Dynamic Discontinuous and Hysteretic Systems
Authors: Lacarbonara Walter , Vestroni Fabrizio , Capecchi Danilo 
Published: February 2021

Abstract
A numerical algorithm is proposed to compute variation of periodic solutions and their codimension-one bifurcations in discontinuous and hysteretic systems in the relevant control parameter space. For dynamic systems with discontinuities and hysteresis, some components of the associated vector fields are nondifferentiable. Therefore, one cannot resort on classical numerical tools based on the evaluation of the Jacobian of the vector field for path-following analyses. Using the pertinent state space, periodic orbits are sought as the fixed points of a Poincaré map based on an appropriate return time. The Jacobian of the map is computed numerically via either a forward or a central finite-difference scheme and a Newton-Raphson procedure is used to determine the fixed points. The continuation scheme is a pseudo-arclength algorithm based on arclength parameterization. The eigenvalues of the Jacobian of the map — Floquet multipliers — are computed to ascertain the stability of the periodic orbits and the associated bifurcations. The procedure is used to construct frequency-response curves of a bilinear, a Masing-type, and a Bouc-Wen oscillator in the primary and superharmonic frequency ranges for various excitation levels. The proposed numerical strategy proves to be very effective in capturing a rich class of solutions and bifurcations — including jump phenomena, pitchfork (symmetry-breaking), and period-doubling.
A0 Wave in a Submerged Stiffened Cylindrical Shell
Authors: Baillard André , Conoir Jean-Marc , Décultot Dominique , Maze Gérard , Klauson Aleksander , Metsaveer Jaan 
Published: February 2021

Abstract
The backscattering of a normal incident plane acoustic wave by a stiffened cylindrical shell is considered. The studied cylindrical shell is made of stainless steel and its internal to external radius ratio is b/a = 0.98. The shell submerged in water is strengthened by an internal plate of the same material and thickness, which is diametrically soldered.
As for the unstiffened shell, A wave (Scholte-Stoneley wave) and S0 wave (first symmetrical Lamb wave) are detected in the frequency range investigated (50–200 ka where k is the wave number in water). On the contrary, the presence of the plate into the tube allows the detection of A0 wave (flexural Lamb wave) whereas it is not observed for the unstiffened shell, owing to the attenuation of the wave during the propagation around the tube. In particularl, A0 wave could be reflected on the junction with enough energy to re-emit in water. Furthermore, wave type conversions are allowed by way of the junctions: S0–A0 wave conversions are observed.
Modal Parameters Estimation and Model Order Selection of a Structure Excited by a Random Force
Authors: Larbi N. , Lardies J. 
Published: February 2021

Abstract
A multivariate maximum likelihood procedure for the estimation of modal parameters is presented. The vibrating system is excited by a random force and sensors output only are used to estimate the natural frequencies and damping coefficients of the system. The method works in time domain and a vector autoregressive moving average (VARMA) process is used. The information about modal parameters is contained in the multivariate AR part, which is estimated using an iterative maximum likelihood algorithm. This algorithm uses a score technique and output data only. The order of the AR part is obtained via the Minimum Description Length associated with an instrumental variable procedure. Experimental results show the effectiveness of the method for model order selection and modal parameters estimation.
Stochastic Stability of a Universal-Joint Driven Torsional System
Authors: Asokanthan S. F. , Wang Xiao-Hui 
Published: February 2021

Abstract
Torsional instabilities in a two-degree-of-freedom system driven by a Hooke’s joint due to random input angular speed fluctuation are investigated. Linearised analytical models are used for calculating the largest Lyapunov exponent. Instability behaviour is then characterised by examining the sign of this exponent. Conditions for the onset of instability via sub-harmonic parametric resonances has been shown to coincide with those for the deterministic case. However, the onset of instability via sum as well as the difference type combination resonance is found to be different from that of the deterministic case. The instability conditions for the system under input angular speed fluctuation have been presented graphically in the excitation frequency-excitation amplitude-top Lyapunov exponent space. Predictions for the deterministic and the stochastic cases are compared. The effect of fluctuation probability density as well as that of inertia loads on the stability behaviour of the system has been examined.
Analysis of Dynamic Couplings in Two-Stage Geared Systems
Authors: Raclot J. P. , Velex P. 
Published: February 2021

Abstract
A modular model for the simulation of the dynamic behavior of multi-stage spur and helical gears is presented. It is mostly based on shaft finite elements combined with some specific gear elements which account for torsional-flexural-axial couplings, parametric and external excitations. Each tooth contact on theoretical base planes is assimilated to a line contact and discretized in accordance with the contact line evolutions when pinions and gears are rotating. A local stiffness and a normal deviation which represent gear tooth elasticity and tooth shape modifications or/and errors are associated with each cell of the time-dependent grid.
Seeking particular stable solutions only, the equations of motion are linearized and solved by using a specific spectral method which has been adapted to parametrically excited systems submitted to broad band parametric and external excitations.
Numerical simulations (dynamic transmission errors and displacements) have been performed for two different two-stage geared trains, i. e., a dual speed reducer (two pinion-gear pairs) and a dual mesh reverse idler (3 gears). The role and the definition of profile modifications (short/long reliefs), the contributions of pitch errors and the influence of the mesh relative orientation on the system dynamic behavior are examined. Finally, the nature and the intensity of the inter-mesh couplings in a double stage geared unit are discussed.
Numerical Simulation of Nonlinear Spur Gear Dynamics
Authors: Arakere Nagaraj K. , Nataraj C. 
Published: February 2021

Abstract
An analytical investigation of the nonlinear dynamics of a high-speed spur-gear pair supported on journal bearings is presented. Dynamic tooth loads result from the interaction between periodic variation of gear mesh stiffness, involute tooth profile errors and gear rotor dynamics. Accurate estimation of dynamic tooth loads, as the gear teeth engage and disengage, is critical for fatigue life estimation. Load-deflection characteristics of a spur gear mesh and the periodically varying gear mesh stiffness is developed using a finite element model. Relative displacement between the gear teeth (transmission error) due to tooth deflection along the line of action is evaluated. The coupled torsional-lateral vibrations of a spur-gear pair supported on journal bearings is modeled as a six degree of freedom system. The time dependent radial and tangential forces acting on the gear shaft supported on journal bearings is evaluated. Short bearing theory is used for modeling the journal bearing dynamics. The resulting nonlinear equations of motion are numerically integrated to obtain gear and pinion whirl orbits due to unbalance excitation and dynamic tooth load variation. Dynamic tooth loads are compared with the mean load due to torque transmission.
New Higher Order Numeric Quadratures for Regular or Singular Functions on an Interval: Applications for the Helmholtz Integral Equation
Authors: Helluy Philippe , Maire Sylvain , Ravel Patrice 
Published: February 2021

Abstract
A high order integration method is presented for regular or singular integrands over an integral. This method appears to be very useful to compute the integrals of the green function in the numerical resolution of boundary integral equations.
Simulation Method of Torsional Vibration Waveform of Reciprocating Engine Crankshaft Systems by Transition Matrix Method
Authors: Wakabayashi Katsuhiko , Honda Yasuhiro , Kodama Tomoaki , Okamura Hiroshi 
Published: February 2021

Abstract
The torsional vibration of the crankshaft system of high speed diesel engines has become more excessive with the increase of engine power and with the decrease of engine rigidity. So it is necessary in the design stage to improve accuracy in the calculation of maximum torsional vibration amplitude at resonant engine speed. At first, this paper refers to a method for obtaining experimentally engine damping that is necessary for the calculation of torsional vibration. If the value of the damping cannot be accurately estimated, the accuracy of the calculated result is still not satisfactory. In this experiment, the decay constant is obtained from the record of the damped, free torsional vibration waveforms which can be got by stopping abruptly combustion in steady operating. It is also shown that the damping ratio, which is approximately 0.03 to 0.04 in high-speed, small diesel engines, can be got from the already-obtained decay constant. Secondly, authors try to calculate directly resultant amplitude by using a step by step transition matrix method. The simulated waveforms of torsional vibration of a high speed diesel engine are compared with the experimental results and it is shown that the calculated results by the transition matrix method are accurate. At the same time, this paper refers to a method for the estimation of engine damping coefficient that is necessary for the calculation of torsional vibration. In this method, the damping coefficient can be got from the previously obtained damping ratio.