bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modal Characteristic of Cantilevered Beams and Plates: A Study of Transition From Beam-Like to Plate-Like Behaviour
Authors: Tangchaichit K. , Oyadiji S. O. 
Published: February 2021

Abstract
The paper presents the finite element (FE) analysis of the free vibrations of cantilevered aluminium alloy beams and plates of 5mm thickness and of length-to-breadth ratios ranging from a ratio of 20 for a beam down to a ratio of 0.25 for a plate. The analysis was carried out using the ABAQUS FE programme. For each ratio, a total of 20 natural frequencies and mode shapes were predicted. The objective of the paper was to demonstrate that a transition zone for beam-like to plate-like behaviour of structural components can be approximately defined for various length-to-breadth ratios. It is shown that the frequency parameters of cantilevered plates asymptotically approach the frequency parameters of cantilevered beams at high length-to-breadth ratios. In addition, it is shown that at the transition point for beam-like to plate-like behaviour, which occurs at small length-to-breadth ratios, the difference between the frequency parameters of cantilevered beams is less than the frequency parameters of cantilevered plates about 3 %.
Intermodal Coupling in Flexible Spinning Disk-Spindle Systems
Authors: Deshpande Moreshwar , Mote C. D. 
Published: February 2021

Abstract
The coupling between the disk and spindle vibration modes of a rotating disk-spindle system is analyzed through the free vibrations of a rotating, flexible spindle with N attached flexible disks. The spindle is modeled as an extensible Kirchhoff-Love rod and the disks as Kirchhoff plates. Couplings between the longitudinal, torsional and flexural deformations of the spindle and the transverse and in-plane motions of the disk are studied analytically. A kinematically rich model captures couplings that have not been predicted previously. Discretization of these modes as a series of orthonormal functions allows for the construction of the characteristic matrix. The structure of this matrix is exploited to partition the eigenvalue problem into six natural classes and to provide simple, exact rules governing the coupling between the modes of the disk-spindle system. The longitudinal spindle vibration modes and the zero nodal diameter transverse disk modes are coupled inertially at all rotation speeds. The torsional spindle modes couple to the zero nodal diameter in-plane disk modes at all non-zero rotation speeds. This coupling is absent in a stationary disk-spindle system. For non-zero rotation speeds, the flexural modes of the spindle in the two orthogonal planes containing the undeformed spindle centerline and the one nodal diameter transverse and in-plane disk modes couple. The one nodal diameter transverse disk modes couple to the one nodal diameter in-plane disk modes through the flexural compliance of the spindle; this coupling cannot be observed through study of the disk alone.
Linear In-Plane Free Vibration of a Rotating Disk
Authors: Hamidzadeh H. R. , Dehghani M. 
Published: February 2021

Abstract
This paper discusses linear in-plane free vibration of a homogeneous, isotropic, linear visco-elastic rotating disk. Two-dimensional theory of elastico-dynamic is employed to develop the general governing equations of motion. In this analysis, a constant angular velocity is assumed. The wave equations and Bessel Functions of the first and second kind are utilized to obtain the natural frequencies. Natural frequencies are found for a number of modes with several clamping ratios. These natural frequencies were compared with the available established results. Also, the influence of rotational speed and clamping ratio on the natural frequencies and the mode shapes of vibration are determined. The analysis provides information about the elastic stability of the rotating disks for several modes of vibration.
An Analytical Solution for the Nonlinear Vibration of Rotating, Thin Disks
Authors: Luo Albert C. J. , Mote C. D. 
Published: February 2021

Abstract
The response, natural frequencies for the linear and nonlinear vibrations of rotating disks are given analytically through the Luo and Mote’s plate theory of 1998. The results for the nonlinear vibration can reduce to the ones for the linear vibration when the nonlinear effects vanish, and they are applicable to disks experiencing large-amplitude displacement or initial flatness and waviness. The natural frequencies for symmetric and asymmetric responses of a 3.5-inch diameter computer memory disk as an example are predicted through the linear theory, the von Karman theory and the new plate theory. The hardening of rotating disks occurs when nodal-diameter numbers are small and the softening of rotating disks occurs when nodal-diameter numbers becomes larger. The critical speeds of softening disks decrease with increasing deflection amplitudes.
Frequency Clusters in the Spectrum of Annular Cylinders
Authors: Tzou K. I. , Wickert J. A. , Akay A. 
Published: February 2021

Abstract
As the length of a traction-free annudar cylinder is increased, distinct members within any family of radial or longitudinal shear modes have natural frequencies that asymptotically approach a common non-zero value. Such modes, potentially having significantly different numbers of nodes along the cylinder’s generator, can have natural frequencies that are indistinguishable from one another within the resolution of test equipment or numerical simulation. The three-dimensional vibration model discussed here predicts the formation of narrow “frequency clusters” with the cylinder’s increasing length, the converged value of which bounds from below the frequencies of all modes within a particular family. In addition to these spectral characteristics, frequency clusters have implications for the forced response of annular cylinders. For the particular families of modes that are of interest here, the steady state harmonic response at frequencies near a cluster can be spatially confined with displacements that decay rapidly away from the point of maximum response. At other driving frequencies, the response is distributed more uniformly along the length of the cylinder. The derived analytical model is compared with results from laboratory measurements, and from the predictions of wave propagation theory in the limit of infinite cylinder length.
An Explicit Scheme for Structural Dynamics Analysis
Authors: Tchamwa Bertrand , Conway Ted , Wielgosz Christian 
Published: February 2021

Abstract
The purpose of this paper is to introduce a new simple explicit single step time integration method with controllable high-frequency dissipation. As opposed to the methods generally used in structural dynamics, with a consistency experimentally chosen of second order, the new method is only first-order-consistent but yields smaller numerical errors in low frequencies and is therefore very efficient for structural dynamic analysis.
The new method remains explicit for any structural dynamics problem, even when a non-diagonal damping matrix is used in linear structural dynamics problem or when the non-linear internal force vector is a function of velocities. Convergence and spectral properties of the new algorithm are discussed and compared to those of some well-known algorithms. Furthermore, the validity and efficiency of the new algorithm are shown in a non-linear dynamic example by comparison of phase portraits.
Vibration Control of a Rigid-Flexible Satellite During Attitude Maneuver
Authors: DeSouza Luiz Carlos Gadelha , DaSilva Silmara Alexandra 
Published: February 2021

Abstract
The paper presents the results of an active structural vibration control of a flexible satellite performed by a proof-mass actuator (PMA) during an attitude rotation maneuver. The satellite investigated is composed of a rigid rub plus a cantilevered flexible beam with the PMA located at the beam free end. As the satellite maneuvers from rest to a pre-defined position, the rigid body motion can excite the flexible part of the satellite. The PMA tasks is to damp-out any residual vibration caused by this maneuver efficiently. The rigid/flexible satellite is modeled, using a relatively simple structural dynamics approach. Having found the vibration modes of the structure, expressions for kinetic and potential energy are derived. Lagrange’s equation is then applied to obtain the satellite equations of motion. The PMA gain selection is based oil an analytical approach which shows that the pole and zero of the fundamental mode is dominant. The efficiency of the PMA using velocity feedback with a PI control law was examined by numerical simulations for different control maneuvers strategies. It was shown that one such controller has damped the residual flexible vibration successfully. However, it was also shown that the control system efficiency is function of the maneuver strategy.
Hybrid Approach to Tomographic Reconstruction of Bubbles in Two-Phase Flows Using Algebraic Reconstruction Technique (ART), Genetic Algorithms (GA) and Simplex Method
Authors: Rajesh A. , Kihm K. D. , Yang L. , Yen J. 
Published: February 2021

Abstract
Main hurdles in the application of genetic algorithms to complex problems are two fold. One is the high computational cost due to their slow convergence rate. The other is to reduce the number of input parameters of a conventional genetic algorithm as in the case of tomographic reconstruction of bubbles. In our present work great strides have been made to alleviate both the problems by using a Hybrid model of Algebraic Reconstruction Technique (ART), Simplex Method and Genetic Algorithm (GA). Our results showed that the hybrid approach is an effective and robust optimization image reconstruction technique.
Singular Perturbation Analysis of an Electrohydraulic Servo-Drive With Discontinuous Reduced Dynamics
Authors: Manhartsgruber Bernhard 
Published: February 2021

Abstract
This paper deals with the position control of a hydraulic servo-drive for translatory motion. The application of a nonlinear composite feedback control based on singular perturbation methods (Kokotovic, Khalil & O’Reilly 1986) is described. A comparison with linear output and state feedback shows the benefits of nonlinear control. The nonlinear design uses feedback linearization for the reduced system and simple proportional feedback for the control of the pressure difference (fast system). The feedback linearization results in a standard second order behavior of the reduced system with cutoff frequency and damping as decoupled design parameters. The proposed method is especially suitable for oscillation drives. Experimental results are given for step responses and sine tracking.
The Estimation of Viscous and Coulomb Damping in Harmonically Excited Oscillators
Authors: Liang J.-W. , Feeny B. F. 
Published: February 2021

Abstract
This paper proposes a simple identification algorithm for estimating both viscous and dry friction in harmonically forced single-degree-of-freedom mechanical vibration systems. The method is especially suitable for the identification of systems for which the traditional free-vibration scheme is difficult to implement. Numerical simulations are included to show the effectiveness of the proposed algorithm. A numerical perturbation study is also included for insight on the robustness of the algorithm.
A Finite Element Analysis of Friction Damping in a Slip Joint
Authors: Chen Weijiang , Deng Xiaomin 
Published: February 2021

Abstract
Micro-slip along frictional interfaces often provides the dominant damping mechanism in a built-up structure and plays an important role in the dynamic behavior of the structure. This paper presents the results of a finite element study of the effect of dry friction on the damping response of a slip joint. The emphasis of this paper is to understand the evolution of the slip and stick regions along the joint interface during loading and to quantify the amount of energy dissipation during cyclic loading and its dependence on structural and loading parameters. Finite element predictions have been compared to experimental measurements and early analytical predictions in the literature. This study seems to demonstrate the potential of the finite element method in providing adequate “numerical” test data for formulating lumped-parameter structural models that can simulate the nonlinear dynamic behavior of bolted joints.
A Design Optimization Process Based on an Energy Finite Element Formulation
Authors: Borlase George , Vlahopoulos Nickolas , Garza-Rios Luis Octavio 
Published: February 2021

Abstract
The Energy Finite Element Analysis (EFEA) offers an alternative solution to the established Statistical Energy Analysis (SEA) for simulating the vibration of large scale structures. A brief theoretical overview and comparison of the two methods is presented first. Numerical models for a fishing boat are utilized for a comparison between the two formulations. In order to demonstrate the powerful capabilities of EFEA in the area of simulation based design, an optimization routine is integrated with an EFEA solver. The optimized distribution of damping over the hull of a vessel is computed. The formulation of the optimization process is presented. The definition of the design variables, the objective function, and the constraints is discussed. The flow chart of the optimization process, and a comparison between the initial and the optimized design are presented.
Modeling of Track-Wheel-Terrain Interaction for Dynamic Simulation of Tracked Vehicle Systems
Authors: Ma Zheng-Dong , Perkins Noel C. 
Published: February 2021

Abstract
A mathematical model of track-wheel-terrain interaction is presented herein to support the dynamic simulation of tracked vehicles. This model combines approximate and known constitutive laws for terrain response with a new representation for the track element. The resulting track-wheel-terrain model allows the computation of the track tension and the normal and shear forces at the track-terrain interface as the track negotiates terrain of arbitrary profile. A key feature of this model is the uniform treatment of contact between the track and the roadwheels and the track and the terrain. Treating both contact problems in the same manner significantly simplifies the problem formulation and also reduces difficulties in computing points of track-wheel and track-terrain separation. The model takes the form of a two-point nonlinear boundary value problem that accounts for tension variations along the track (due to the non-uniformly distributed normal pressure and traction), track extensibility, and geometrically large (nonlinear) track deflections. Solutions are obtained using a finite element formulation. Both the model and the solution method are formulated with a view towards implementation within a multibody dynamics code for simulating a full vehicle. Several examples illustrate the capabilities of the proposed model.
Study on Elastic Forces of the Absolute Nodal Coordinate Formulation for Deformable Beams
Authors: Takahashi Yoshitaka , Shimizu Nobuyuki 
Published: February 2021

Abstract
There are three basic finite element formulations which are used in the dynamics of flexible beams. These are the floating frame of reference approach, the finite segment method and the large rotation vector approach. Recently, the absolute nodal coordinate formulation was proposed by A.A.Shabana et al. In this procedure, there is no need to transform the element matrices since the equations of motion are defined in terms of absolute nodal coordinates. The mass matrix becomes constant, whereas the stiffness matrix becomes nonlinear function of time, even in case of linear elastic problems. One possible method to avoid such cumbersome of the absolute nodal coordinate formulation in calculating clastic forces is to assume the infinitesimal deformation theory against beams undergoing large rotation.
In this paper, a new formulation to calculate the elastic forces and add the rotary inertia effects in the expression of the inertia forces. This formulation is based on the assumption that the deformations within each element remain very small. The expression of the resulting clastic force is simple, and the need for performing coordinate transformation is avoided. As the method assumes that the deformation of the beam from a selected beam axis is very small, a large number of finite elements is required for large deformation problems. However, the formulation has been found to be efficient for large rotation and medium deformation problems. Numerical examples are demonstrated for this formulation by using planar flexible pendulum problems.
A Numerical Approach to Solving Flexible Multibody Systems Using the Absolute Nodal Coordinate Formulation
Authors: Yakoub R. Y. , Shabana A. A. 
Published: February 2021

Abstract
By utilizing the fact that the absolute nodal coordinate formulation leads to a constant mass matrix, a Cholesky decomposition of the mass matrix can be used to obtain a constant velocity transformation matrix. This velocity transformation can be used to express the absolute nodal coordinates in terms of the generalized Cholesky coordinates. In this case, the inertia matrix associated with the Cholesky coordinates is the identity matrix, and therefore, an optimum sparse matrix structure can be obtained for the augmented multibody equations of motions. The implementation of a computer procedure based on the absolute nodal coordinate formulation and Cholesky coordinates is discussed in this paper. A flexible four-bar linkage is presented in this paper in order to demonstrate the use of Cholesky coordinates in the simulation of the small and large deformations in flexible multibody applications. The results obtained from the absolute nodal coordinate formulation are compared to those obtained from the floating frame of reference formulation.
Modular Modeling and Simulation of Multibody Systems
Authors: Kübler Ralf , Schiehlen Werner 
Published: February 2021

Abstract
Complex engineering systems such as automobiles are often relieved by a modular approach for modeling and simulation to make it treatable by a team of engineers. The functional decomposition is due to different engineering disciplines and engineering intuition.
The resulting subsystems are considered as dynamic blocks with inputs and outputs. The global system structure is given by interconnections of inputs and outputs of corresponding blocks. Since the global system structure is independent of the internal subsystem description this procedure allows for independent and parallel modeling of the internal dynamics of each block. Although this approach is widely used in control theory and also more and more in mechatronics, the mechanical parts are traditionally modeled as one multibody system.
In this paper a modular formulation of multibody systems is proposed which is based on the block representation of a multibody system with corresponding input and output quantities. Multibody system blocks can be connected by means of arbitrary joints and coupling elements resulting in a global system with high degree of modularity in the modeling procedure. The option to use different simulation tools for modular simulation of the global system behavior has the potential to even more exploit the modular system structure.
Optimal Motions for Underactuated Manipulators
Authors: Sohl Garett A. , Bobrow James E. 
Published: February 2021

Abstract
In this paper we develop an algorithm for solving optimal control problems for underactuated open chain manipulators. A local solution to the nonlinear optimal control problem is obtained using a constrained parameter optimization procedure. As part of the algorithm, a recursive dynamics formulation for underactuated serial chains is derived using matrix exponentials and the geometric framework provided by Lie groups and Lie algebras. The benefit of the matrix exponential formulation is the ability to derive explicit analytic gradients of the dynamics. These gradients are essential for our algorithm since the parameter optimization is ill-conditioned aid approximate numerical gradients do not produce meaningful solutions. Interesting example solutions are provided for a two dof acrobot, a simple branched chain and a 7 dof human diver.
Minimum Jerk Traction Control of a Wheeled Mobile Robot Moving Over a Hump
Authors: Ayalew A. , Lai E. , Oyadiji S. O. 
Published: February 2021

Abstract
A new technique is presented for the minimization of jerk for wheeled mobile robots (WMRs) traveling on uneven terrain. A robot may jerk as it traverses a road obstacle. Consequently, wheel-ground contact loss is one of the undesirable dynamic effects that can cause loss of control and robot instability. By considering the dynamics of the robot with respect to the longitudinal, pitching and vertical motions of the platform, the new technique calculates the dynamic compensation needed to ideally counter the onset of jerk by controlling the magnitude of the input drive torque to the wheels. Simulation results showed that the technique has the potential to substantially reduce the magnitude of jerk of a WMR during longitudinal maneuver over a road obstacle with a positive gradient.
Free and Forced Vibration of a Kinked Cantilever Beam
Authors: Reddy B. S. , Simha K. R. Y. , Ghosal A. 
Published: February 2021

Abstract
In this paper we use the assumed modes method to derive an analytical model of a kinked cantilever beam of unit mass carrying a kink mass (mk) and a tip mass (mt). The model is used to study the free and forced vibration of such a beam. For the free vibration, we obtain the mode shape of the complete beam by solving an eight order polynomial whose coefficients are functions of the kink mass, kink angle and tip mass. A relationship of the form f(mk,mt,δ)=mk+mt(4+103cosδ+23cos2δ)=constant appears to give the same fundamental frequency for a given kink angle, δ, and different combinations of kink mass and tip mass.
To derive the dynamic equations of motion, the complete kinked beam mode shape is used in a Lagrangian formulation. The equations of motion are numerically integrated with a torque applied at the base and the tip response for various kink angles are presented. The results match those obtained from a traditional finite element formulation.
Multirate Integration for Real-Time Simulation of Wheel Loader Hydraulics
Authors: Buzdugan Laurenţiu I. , Balling Ole , Lee Peter Chien-Te , Balling Claus , Freeman Jeffrey S. , Huck Frank 
Published: February 2021

Abstract
This paper details a real-time simulation of an articulating wheel loader, which is comprised of a multibody system modeling the chassis and the bucket assembly and a set of subsystems. The hydraulic subsystem is modeled by a set of ODE’s which represent the oil pressure fluctuations in the system. An Adams-Bashforth-Moulton integration algorithm has been implemented using the Nordsieck form to develop a constant step-size multirate integration scheme, modeling the interaction between the hydraulic subsystem and multibody dynamics models. An example illustrating the simulation of a wheel loader bucket operation is presented at the end of the paper.
Influence Coefficients Obtained by Hammer Beat Permit Significant Time Savings When Balancing Simple Flexible Rotors
Authors: Wiese D. , Breitwieser M. 
Published: February 2021

Abstract
The following paper presents a method for balancing simple flexible rotors with the help of influence coefficients obtained by hammer beat. The method permits time savings of approx. 50% compared to the conventional influence coefficient method. Initial positive results obtained on a flexible roll are also presented.