bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Parameter Optimization of Contact Force Models on the Impact Dynamic Responses
Authors: Lankarani H. M. , Wu F. 
Published: March 2021

Abstract
Reducing the severity of an impact to a structure or a multibody system is a significant aspect of engineering design. This requires the knowledge of variations of the resulting contact forces and also how these contact forces can be reduced. This paper presents an optimization methodology for the selection of proper parameters in the contact/impact force models so as to minimize the maximum value of the contact force. A two-particle model of an impact between two solids is considered, and then generalized to the impact analysis between two bodies of a multibody system. The concept of effective mass is presented in order to compensate for the effect of joint forces or impulses. The system is reduced to a single degree-of-freedom mass-spring-damper vibro-impact system. A single differential equation of motion in the direction of relative indentation of local contact surfaces is derived. Different contact force models of hysteresis form including linear and nonlinear models are described. An optimization problem is then formulated and solved by using the method of modified feasible direction for constrained minimization. A numerical integrator is used at every design iteration to obtain the system dynamic response for a given set of design variables. The objective function is to minimize the peak acceleration of the system equivalent mass resulting from the contact force. Comparison of the system with optimal parameters and non-optimal one shows that the peak contact force is greatly reduced for the optimal one. Since these parameters reflect the material properties (stiffness and damping) of the impacting bodies or surfaces, suitable materials may then be selected based upon the information provided by this optimization procedure. It is observed that the materials, which have good crashworthiness properties should posses capability of dissipating impact energy both in the forms of permanent indentation and internal damping friction. Based upon the analysis of the impact responses, mechanism of energy dissipation, and the typical force-indentation diagram for the high energy absorption materials obtained from experiments, a new contact force model is proposed which could precisely describe the impact response of high energy-absorption materials.
Recent Developments on Nonstationary Parametric Responses of Rectangular Plates
Authors: Ostlguy Germain L. , Lavigne Patrice 
Published: March 2021

Abstract
The non-stationary parametric response of a rectangular plate during a logarithmic sweep of the excitation frequency through a system resonance is studied using five different techniques of solution. Considering only the case of principal parametric resonance, the continuous system is spatially discretized by means of a single-term modal approximation for the lateral displacement. The general form of the resulting nonlinear temporal equation of motion for the damped parametric vibrations in any spatial mode is analyzed using the multiple time scales method and the method of asymptotic series expansion developed by Mitropolsky, in the first and second approximation. The non-stationary response of the plate during transition through parametric resonances is also evaluated by direct integration of the temporal equation of motion and the results obtained by the different techniques are compared. The non-stationary response displays several phenomena depending on the conditions of in-plane loading, the amount of damping, the initial conditions, and the rate as well as the direction of the sweep. The validity of these results is ascertained experimentally.
Numerical Simulation of Multibody Systems With Time Dependant Structure
Authors: Joli Pierre , Pascal Madeleine , Gibert René 
Published: March 2021

Abstract
Current dynamic simulation programs are able to calculate the continuous motions of articulated systems or more general systems of rigid bodies in the absence of contact between members of the system or between the system and its environment. Some are able to simulate the effects of isolated contacts and impacts but none are able to simulate the motion with unrestricted multiple concurrent contacts.
However, in special robotic programs such as robots performing assembly tasks or walking, it would be very interesting to simulate appropriate commands before implementing them on the robots.
This paper develops intrinsic problems of collision to produce an efficient computational algorithm. This algorithm handles the detection of collision in three dimensions, the reduction of the integration step in order to avoid interpenetration between the bodies before impact, the jump velocity caused by a new collision and indicator magnitudes which determine the addition or deletion of constraints.
An Experimental Study of Bifurcation and Chaos in a Dynamically-Buckled Magneto-Elastic System
Authors: Cusumano J. P. , Sharkady M. T. 
Published: March 2021

Abstract
Results are presented from an experimental study of the dynamics of a lightly-damped, flexible beam which is buckled and unbuckled magnetically. The system is parametrically excited by driving an electromagnet with a low-frequency sine wave. For voltage amplitudes in excess of the static bifurcation value, the beam will slowly switch between the one and two-well configurations. Experimental static and dynamic bifurcation results are presented. Poincaré sections of a chaotic steady-state are obtained for various values of the driving phase, and the correlation dimension of the chaotic attractor is estimated. Singular system analysis is used to demonstrate the effect of delay time on the noise level in delay-reconstructions, and to provide an independent check on the dimension estimate by directly estimating the number of independent coordinates from time series data.
Identification of Parameters for a Vehicle Submitted to a Crash
Authors: Boneill C. , Mizzi J. P. 
Published: March 2021

Abstract
The mathematical modelling of a vehicle when it is driving into a fixed or deformable barrier or into another vehicle must allow to reproduce the deceleration field inside it and its structural and kinematic behaviour. Although a detailed view can be obtained using finite element modelling, the more global multibody approach has the advantage of requiring considerably lower computing costs, and therefore of studying quickly the behaviour for many input data.
The main difficulty in executing the above procedure is to determine the laws governing the behaviour of the deformable links. These can first be estimated either by finite element calculations, or by static or dynamic tests. This approach can be improved using an identification methodology, provided that the kinematics in a crash trial is well known.
A non parametric identification method has been considered. But the results have not been satisfactory enough.
Conversely, if an initial estimate of the set of parameters is available, a parametric identification can be preferred. Several have been tested. Once their respective stability and strength had been determined on one-dimensional test models with one and two degrees of freedom. Predictivity and reliability trials in the presence of noisy data have been envisaged. The results have permitted to highlight which is the best adapted to solve the problem.
We have applied the chosen approach in the case of the impact of guided vehicles (the TGV Atlantic high-speed “bullet” train) and road vehicles.
Flexural-Torsional Response of a Cracked Rotating Shaft With a Disk During Passage Through a Critical Speed
Authors: Suherman Surjani , Plaut Raymond H. 
Published: March 2021

Abstract
The nonstationary behavior of a cracked rotating shaft with a disk is analyzed. The shaft is accelerated or decelerated through a critical speed, and both flexural and torsional responses are examined. A breathing crack is considered, which is either completely open or completely closed at any given time. Forces due to eccentricity, gravity, and internal and external damping are included. Galerkin’s method is utilized, and the resulting bilinear equations are integrated numerically. The effects of acceleration and deceleration rate, internal and external damping, crack location and depth, and location, mass, and eccentricity of the disk are investigated. Application of the results to detection of cracks is discussed.
Prediction of the Dynamic Behavior of Systems Modelled With Periodic Coefficients: Application to Asymmetric Rotors
Authors: Sayettat-Beley Aline , Couderc Phillippe , Ferraris Guy , Lalanne Michel 
Published: March 2021

Abstract
This work is concerned with rotors having unequal area moments of inertia which necessarily lead to equations with periodic coefficients when the bearings are asymmetric. Following a study of the main phenomena and responses to classical forces on simple models, stability and unbalance response of a large finite element model are considered using a pseudo-modal technique and Floquet theory. Results obtained are satisfactory and show that the method is effective in accurately predicting the dynamic behavior of asymmetric rotors modelled with a significant number of degrees of freedom.
Liapunov-Floquet Transformation: Computation and Applications to Periodic Systems
Authors: Pandiyan R. , Bibb J. S. , Sinha S. C. 
Published: March 2021

Abstract
In this paper, a new analysis technique in the study of dynamical systems with periodically varying parameters is presented. The method is based on the fact that all linear periodic systems can be replaced by similar linear time-invariant systems through a suitable periodic transformation known as the Liapunov-Floquet (L-F) transformation. A general technique for the computation of the L-F transformation matrices is suggested. In this procedure, the state vector and the periodic matrix of the linear system equations are expanded in terms of the shifted Chebyshev polynomials over the principal period. Such an expansion reduces the original differential problem to a set of linear algebraic equations from which the state transition matrix (STM) can be constructed over the period in closed form. Application of Floquet theory and eigen analysis to the resulting STM yields the L-F transformation matrix in a form suitable for algebraic manipulations. The utility of the L-F transformation in obtaining solutions of both linear and nonlinear dynamical systems with periodic coefficients is demonstrated. It is shown that the application of L-F transformation to free and harmonically forced linear periodic system directly provides the conditions for internal and combination resonances and external resonances, respectively. The application of L-F transformation to quasilinear periodic systems provides a dynamically similar quasilinear systems whose linear parts are time-invariant and the solutions of such systems can be obtained through an application of the time-dependent normal form theory. These solutions can be transformed back to the original coordinates using the inverse L-F transformation. Two dynamical systems, namely, a commutative system and a Mathieu type equation are considered to demonstrate the effectiveness of the method. It is shown that the present technique is virtually free from the small parameter restriction unlike averaging and perturbation procedures and can be used even for those systems for which the generating solutions do not exist in the classical sense. The results obtained from the proposed technique are compared with those obtained using the perturbation method and numerical solutions computed via a Runge-Kutta type algorithm. The technique is found to be very powerful in the analysis of linear and nonlinear periodic dynamical systems.
A Stability Criterion for the Mathieu-Hill Equation
Authors: Bhattacharyya Ranjan 
Published: March 2021

Abstract
A criterion for the stability of the solutions of the Mathieu-Hill equation containing even periodic potential is developed. The criterion is based on a result derived by Hill relating the infinite determinant, the Floquet exponent, and the constant term of the even Fourier series expansion of the potential function. It is shown that the criterion is easy to apply in practical problems to obtain stability maps in a suitable parametric plane. In the special case of the Mathieu equation, the criterion is applied to generate the stability maps that compare fairly well with those obtained by other well-known, but more tedious methods. A qualitative relation between the stable and unstable regions of the stability map and the infinite determinant is also provided. In another example, the problem of undamped, finite uniaxial vibrations coupled with a superimposed small twisting oscillation of a rigid disk attached to a hyperelastic neo-Hookean shaft is briefly discussed to bring out the usefulness of the criterion when applied to problems of engineering interest. It is found that the stability of small twisting motion is governed by the Mathieu-Hill equation containing an even periodic potential. Use of the criterion is made to generate the stability maps in a relevant parametric plane. This stability chart can be directly used in designing such a shaft-disc assembly to avoid undue high amplitude torsional vibration.
Transient Vibrations of Nonlinear Systems: Global Dynamics and Chaotic Transients
Authors: Soliman Mohamed S. 
Published: March 2021

Abstract
In this paper a new approach in the global transient analysis of nonlinear systems is presented; it has the advantages of being conceptually simpler and at the same time more relevant than one based soley on a stability analysis of the steady-state motions. We address the problem of analysing the global transient stability of nonlinear systems in terms of basins of attraction. We show that at a forcing level that is considerably smaller than that at which the steady state attractor loses its stability, there may exist a rapid erosion and stratification of the basin, signifying a global loss of engineering integrity of the system. This conclusion is reinforced by the fact that basin boundaries can become fractal, resulting in chaotic transients, adding a new degree of uncertainty in the response.
The techniques developed are then applied to a ship roll model with cubic and quintic nonlinearities as well as linear plus cubic damping characteristics.
Nonlinear, Damped Vibrations of Sandwich Plates With Time-Dependent Temperature
Authors: Lukasiewicz S. , Xia Z. Q. 
Published: March 2021

Abstract
The paper studies the effect of the rapid change of temperature on the vibrations of simply supported sandwich plates. It has been taken into consideration that the properties of the facings and of the core of the sandwich plate materials change with the change of the temperature. The effects of the viscoelastic damping and geometrical nonlinearities on the behaviour of the plate have also been included. It was found that the rapid change of temperature affects the amplitude and frequency of the vibrations.
Passive Control in Mobile Robots via Suspension Design
Authors: Wiens Gloria J. , Tsai Hungder 
Published: March 2021

Abstract
In this paper, the role of dynamic coupling effects in mobile robotic systems is investigated. For this study, the equations of motion for a rigid-body model of a single-linked mobile robot are derived using Lagrangian dynamics. As possible passive control elements, various spring-damper combinations for the vehicle’s suspension system are applied to the model. Analysis and design of the passive controller is executed with implementation of a computer simulation based algorithm and performance measures. The algorithm is based on the differences between the coupled and decoupled models of the mobile robotic system. The decoupled model is one in which the mobile robot is modeled as two isolated subsystems, arm and vehicle. Subsequent to the computer simulation, the appropriate passive control elements and system parameters and trajectory selections for the elimination of the instability and inaccuracies due to dynamic coupling are recommended. Via this approach in reducing the dynamic coupling effects, it is predicted that the system’s existing active controller will be able to more effectively control the system at much higher speeds and for a larger number of applications than before. That is, the arm will not have to be held stationary while the vehicle is moving or vice versa.
Computer Simulation of Dynamical Behavior of Self-Propelled Gurney
Authors: Szydlowski Wieslaw M. , Sastry Srinivas 
Published: March 2021

Abstract
The conventional gurneys used in hospitals to move patients from room to room have one main disadvantage: they are difficult to control. A typical gurney has a form of an oblong table moving on four castor wheels. The vehicle is difficult to maneuver, especially on corridor turns, and usually requires two operators — each at one end.
Dr. J. Bleicher from the St. Joseph’s Hospital in Omaha, Nebraska suggested a new type of a self-propelled gurney which would be a cross-breed of a motorized wheelchair and a gurney.
A new type of a gurney would have two additional wheels in the center of the gurney, each connected to a separate DC motor. The torques developed by the motors would be controlled by one operator using a joystick. Applying opposite torques to the controlled wheels would rotate a stationary gurney in place, or would curve the path of a moving gurney.
The position of two additional wheels can be changed, so that the gurney can move sideways, translate in chosen direction or move along a curvelinear path.
The work presented in the paper contains an analysis of the dynamics of such a gurney. A mathematical model of the vehicle was developed to check how much effort is needed on the part of the operator in straight path motion and during negotiating a corner.
The most difficult part of the modelling was a proper description of forces and torques exerted by the ground on the wheels.
The differential equations of motion of the gurney have been numerically integrated, and the dynamical response of the vehicle studied. The results of the computer simulation show a transient oscillatory response of the castor wheels (shimmying) which can be controlled by a proper choice of design parameters of the vehicle.
Generation of Motion Equations for a Tree-Like System of Granular Bodies
Authors: Vinogradov Oleg 
Published: March 2021

Abstract
An arbitrary system of 3D-bodies made out of rigid spheres and arranged topologically in a tree is considered. For such a system explicit expressions for the equations of motion are derived based on the Lagrangian approach. The equations are given in terms of the path matrix characterizing the topological tree. The analytical method of generation of equations of motion makes the computer simulation of the nonsteady motion of the discrete system of bodies more efficient in term of both computer time and accuracy. It is achieved by avoiding operations with large sparse matrices (if the equations were generated numerically) and by cancelling out some terms in Lagrange’s equations analytically.
Intelligent Constrained Layer: An Innovative Approach
Authors: Shen I. Y. 
Published: March 2021

Abstract
This paper is to propose an innovative damping design termed intelligent constrained layer (ICL). This technique integrates active and passive dampings through constrained layer treatments to enhance system reliability and to provide adjustable damping. The proposed ICL damping design consists of a viscoelastic shear layer sandwiched between a piezoelectric constraining cover sheet and the structure to be dampened. According to measured vibration response of the structure, a feedback controller regulates axial deformation of the piezoelectric layer to perform active vibration control. In the meantime, the viscoelastic shear layer provides additional passive damping. The active damping component of this design will produce adjustable and significant damping. The passive damping component of this design will increase gain and phase margins, eliminate spillover, reduce power consumption, improve robustness and reliability of the system, and reduce vibration response at high frequency ranges where active damping is difficult to implement. To model the dynamics of ICL, an eighth-order differential equation governing bending vibration of an elastic beam with the ICL treatment is first derived. Then an ICL treatment using an idealized, distributed sensor and a proportional-plus-derivative feedback controller is illustrated on a semi-infinite elastic beam subjected to standing wave excitations. Numerical results show that ICL will produce significant damping. The allowable deflection slope of the beam in order not to saturate the piezoelectric layer is also calculated.
Localization of Helical Flexural Waves on an Irregular Cylindrical Shell
Authors: Photiadis Douglas M. 
Published: March 2021

Abstract
Small amounts of irregularity are known to produce vibration localization in one-dimensional chains, but the effects on two and three dimensional systems are typically much weaker. We have considered a system with both one and two dimensional aspects, an axisymmetric, irregularly ribbed fluid-loaded cylindrical shell. A new formulation of this problem is given and each mode of the system is shown to be approximately equivilent to a nearest neighbor coupled chain with six degrees of freedom — corresponding to three left going and three right going traveling waves. Using these results all the azimuthal modes have been shown to be localized simultaneously and thus vibrational energy on an irregular cylindrical shell is Anderson localized. The slow flexural waves have been shown to localize separately from the fast waves provided the helical angle of the flexural wave is greater than about Ω1/25°, and for smaller helical angles, exponential localization is expected for distances less than a critical wave mixing length. Our results indicate that strong localization effects occur for the helical flexural waves yielding very short localization lengths of order a single rib spacing.
Formulation of Multiple Belt System and its Dynamic Analysis
Authors: Iwatsubo Takuzo , Arii Shiro , Hasegawa Kei , Shiohata Koki 
Published: March 2021

Abstract
This paper presents a method for analyzing the dynamic characteristics of driving systems consisting of multiple belts and pulleys. First, the algorithm which derives the linear equations of motion of arbitrary multi-coupled belt systems is shown. Secondly, by using the algorithm, the computer program which formulates the equations of motion and calculates the transient responses of the belt system is presented. The fundamental idea of the algorithm is as follows: Complicated belt systems consisting of multiple belts and pulleys are regarded as combinations of simple belt systems consisting of a single belt and some pulleys. Therefore, the equations of motion of the belt systems can be derived by the superposition of the equations of motion of the simple belt systems. By means of this method, the responses of arbitrary multi-coupled belt systems can be calculated. Finally, to verify the usefulness of this method, the simulation results are compared with the experimental results.