bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Set-Based System for Eliminating Infeasible Designs in Engineering Problems Dominated by Uncertainty
Authors: Finch William W. , Ward Allen C. 
Published: February 2021

Abstract
This paper gives an overview of a system which eliminates infeasible designs from engineering design problems dominated by multiple sources of uncertainty. It outlines methods for representing constraints on sets of values for design parameters using quantified relations, a special class of predicate logic expressions which express some of the causal information inherent in engineering systems. The paper extends constraint satisfaction techniques and describes elimination algorithms that operate on quantified relations and catalogs of toleranced or adjustable parts. It demonstrates the utility of these tools on a simple electronic circuit, and describes their implementation and test in a prototype software tool.
Using Key Characteristics to Balance Cost and Quality During Product Development
Authors: Thornton Anna C. 
Published: February 2021

Abstract
Corporations are spending significant resources to reduce the effect of manufacturing variation on product quality as well as adopt lower cost manufacturing and assembly technologies to reduce the end costs in product development. However, to ensure that these investments have a positive return, efforts must be made to put resources into those areas where there will be the largest return. This paper describes a formalized method to make these decisions. The analysis focuses the tradeoff studies on the Key Characteristics (KCs) of the product. KCs, in use in a variety of industries, are the product features that are most sensitive to existing manufacturing and process variation and will affect the end quality of the product. Two examples from the aircraft manufacturing environment are used describe the application of the proposed methods.
Vibration Control of a Distributed Axially Moving String Using Two Actuators
Authors: de Queiroz M. S. , Dawson D. M. , Rahn C. D. , Zhang F. 
Published: February 2021

Abstract
In this paper, we consider the problem of regulating the displacement of an axial moving string using a control force and a control torque applied to the string via a mechanical guide. Given the hybrid model of the web system (i.e., distributed parameter field equation coupled to a discrete actuator equation), a Lyapunov-type analysis is utilized to design exact model knowledge and adaptive control laws that exponentially and asymptotically stabilize the string displacement, respectively. Dynamic simulation results demonstrate the vibration damping provided by the control strategy.
Analysis of Acoustical Properties of a Gear Mechanism
Authors: Podzharov Evgueni I. 
Published: February 2021

Abstract
For an analysis of the acoustical properties of a multistage gear mechanism, a technique was used that combines a dynamic calculation of the mechanism as multimass multicoupling system and the SEA method for the calculation of acoustical energy. The dynamic calculation was used to determine the energy introduced into the mechanism’s gear meshes and the energy transmitted to the housing. The SEA method was used for the calculation of propagation of acoustical energy in the structure and its radiation in the surrounding space. Such a combination permits us to utilize the advantage of dynamic calculation accurately describing the mechanism’s performance and the SEA method for describing an acoustical model having the elements of high mode density in a wide frequency range. Some useful results were obtained which permit us to reduce noise level of the mechanism.
In-Plane Stick-Slip Vibration on the Surface of a Flexible Disc Clamped Between Elastic Sliders
Authors: Ouyang Huajiang , Mottershead J. E. , Cartmell M. P. , Friswell M. I. 
Published: February 2021

Abstract
The in-plane stick-slip vibration of two slider systems which are driven together around the surfaces of either side of a flexible vibrating disc, and the induced transverse vibration of the disc, are investigated. The disc is taken to be an elastic annular plate and each slider has flexibility in the circumferential (in-plane) and transverse directions. The static friction coefficient is assumed to be higher than the kinetic friction coefficient. Because of the friction force acting between the disc and the slider systems, the sliders will oscillate in the stick-slip mode in the plane of the disc. The transverse vibration induced by the oscillating sliders will change the normal forces of the slider systems acting on the disc, which in turn will change the in-plane oscillation of the sliders. Therefore, the in-plane oscillation of the sliders and the transverse vibration of the disc are coupled. For different values of system parameters, the coupled in-plane oscillation of the sliders and transverse vibration of the disc will exhibit quasi-periodic as well as chaotic behaviour.
Typical patterns of chaotic vibration of the slider systems and of the disc are presented in graphs to illustrate the special behaviour of this non-smooth, nonlinear dynamical system. The physical model represents a car disc brakes.
Analysis of Stick-Slip Motion in Coulomb Damped Systems Using Variable Structure System Theory
Authors: Ferri Aldo A. , Heck Bonnie S. 
Published: February 2021

Abstract
The numerical simulation and control design of many systems is hampered by the presence of dry (Coulombic) friction. In particular, the discontinuous nature of the friction law leads to computational difficulties whenever sticking occurs across the frictional interfaces. This paper uses results from Variable Structure System (VSS) theory to develop a model useful for simulating stick-slip motion in a generic system with multiple frictional interfaces. The Variable Structure framework is also used to analyze the errors incurred in the new simulation model. A second approach, motivated by the alleviation of chatter in VSS systems, uses a saturation-type nonlinearity to represent the frictional interface. The accuracy of this approach is analyzed using VSS and singular perturbation theory. The accuracy and numerical efficiency of each method is demonstrated in two numerical examples.
Influence of Internal Structures of High Modal Density on Shell’s Radiation
Authors: Oddo Lionel , Laulagnet Bernard , Guyader Jean-louis 
Published: February 2021

Abstract
The aim of this paper is to study the sound radiation by a cylindrical shell internally coupled with mechanical structures of high modal density. The model is based on a mobility technique. The numerical results show a smoothing of the cylinder’s velocity and radiation spectra associated with an increase of the apparent damping. The use of the S.E.A. method allows us to calculate an additional structural damping of the shell, equivalent to the effect of the internal structures.
Vibroacoustic Source Identification, From Measured Structure Response and Resolution of the Inverse Problem
Authors: Pezerat C. , Guyader J. L. 
Published: February 2021

Abstract
This paper is concerned with the localization of input forces in a two-dimensional system using an inverse vibration method. Using the measured flexural displacements of a plate, one can determine the location and amplitude of the external forces exciting the plate. As in all inverse problems, difficulties arise due to the sensitivity to measurement uncertainties, so that small errors in the measurements could introduce a high noise on the result. An analytical method is developed and involves local estimation of the force distribution using a finite difference scheme, a spatial window and a numerical wavenumber filter. This method needs only the equation of motion of the plate and has the advantage that it can be used with unknown boudary conditions. However, mechanical sources near the boundaries of structures cannot be localized. A numerical simulation and experimental results are shown. The numerical simulation exhibits the influence of noisy displacement measurements on localization. Experiments are described where the localization of an external source and the determination of coupling forces between a plate and a stiffener are accurately found.
Cavitation Driven Impact in a Hydraulic Piston Pump: A Theoretical and Experimental Investigation
Authors: Manhartsgruber Bernhard , Scheidl R. 
Published: February 2021

Abstract
The occurrence of cavitation in a huge hydraulic supply system of a rolling mill which caused a severe defect in an axial piston pump is investigated by a mathematical model of the complex suction system. It comprises wave propagation in pipes and hoses, a detailed model of the pump including each of its nine cylinders, cavitation therein, the charge and discharge processes of these cylinders with the intake duct, and several accessories influencing the hydraulic processes. Results obtained by this model are compared with on-site experiments. Countermeasures which have been proposed are evaluated by our model and their practical examination is reported. Due to the strong nonlinearity of cavitation the dynamical system shows two attracting limit sets, one with and one without cavitation. The operating conditions of the original supply system cause startup conditions which do not lie in the basin of attraction of the non-cavitating attractor.
Dynamics of Distributed Impact Dampers
Authors: King Melvin E. , Sandri Guido 
Published: February 2021

Abstract
In this work, the dynamics of spatially distributed impact dampers are investigated. Typical impact damper configurations consist of a single, rigid mass which moves freely within a cavity that is attached to a lightly damped structure. By tuning the damper’s mass and the cavity’s length (gap-size), the maximum displacement of the structure may be significantly reduced due to the resulting intermittent collisions. Several modifications to the classical impact damper design have been considered in the literature, including (i) multiple-unit dampers, and (ii) granular impact dampers. Both designs have been found to effectively attenuate resonant responses, while simultaneously reducing the severe impact loads, accelerations and noise levels associated with a single-unit damper. An extension of the multiple-unit damper configuration is considered in the present work. The configuration under consideration (referred to as a distributed impact damper) incorporates a number of non-identical single-unit dampers. Whereas multiple-unit dampers composed of identical elements may be tuned to a specified resonant frequency, the proposed distributed impact damper is expected to provide significant attenuation over broad frequency bands. The present work focuses on developing analytical tools with which to study the dynamics of distributed impact dampers. In this regard, methods from non-equilibrium statistical mechanics, including correlation hierarchy, will be used to develop statistical models of the distributed impact damper. Successful completion of this work is expected to provide significant insight into the dynamics of distributed impact dampers, leading to the future development of novel broad-band damping and shock isolation designs.
Piecewise Linear Systems With Time Varying Coefficients
Authors: Natsiavas S. , Theodossiades S. 
Published: February 2021

Abstract
A new method is presented for determining periodic steady state response of piecewise linear dynamical systems with time varying coefficients. As an example mechanical model, a gear-pair system with backlash is examined, under the action of a constant torque. Originally, some useful insight is gained on the type of motions expected by investigating the response of a weakly nonlinear Mathieu-Duffing oscillator, subjected to a constant external load. The information obtained is then used in seeking the appropriate form of approximate periodic solutions of the piecewise linear system. Finally, these solutions are determined by developing a new analytical method. This method combines elements from approaches applied for piecewise linear systems with constant coefficients as well as classical perturbation techniques applied for systems with time varying coefficients. The validity and accuracy of the approach is verified by numerical results. In addition, response diagrams are presented, illustrating the effect of the constant load and the damping on the gear-pair response.
Dynamic Vibration Absorber for a Ropeway Carrier
Authors: Matsuhisa Hiroshi , Nishihara Osamu 
Published: February 2021

Abstract
Ropeways such as gondola lifts have attracted increasing interest as a means of transportation in cities. However, swing of ropeway carriers is easily caused by wind, and usually a ropeway cannot operate if the wind velocity exceeds about 15m/s. The study of how to reduce the wind-induced swing of ropeway carriers has attracted many researchers. It had been said that it was impossible to reduce the vibration of pendulum type structures such as ropeway carriers by a dynamic absorber. But in 1993, Matsuhisa showed that the swing of carrier can be reduced by a dynamic absorber if it is located far above or below from the center of oscillation. Based on this finding, a dynamic absorber composed of a moving mass on an arc-shaped track was designed for practical use, and it was installed in chairlift-type carriers and gondola type carriers in snow skiing sites in Japan in 1995 for the first time in the world. It has been shown that a dynamic absorber with the weight of one tenth of the carrier can reduce the swing to half. The liquid dynamic absorber was also investigated. It has the same damping effect as the conventional solid absorber. It is easy to adjust the natural frequency and the damping ratio, and the structure is simple. Therefore, it will be applied for not only ropeway carriers but also ships and rope suspended bridge and others.
Dynamics of Pipes Containing Pulsative Flow
Authors: Szabó Zsolt , Sinha S. C. , Stépán Gábor 
Published: February 2021

Abstract
Several mechanical models exist on elastic pipes containing fluid flow. In this paper those models are considered, where the fluid is incompressible, frictionless and its velocity relative to the pipe has the same but time-periodic magnitude along the pipe at a certain time instant. The pipe can be modelled either as a chain of articulated rigid pipes or as a continuum. The dynamic behaviour of the system strongly depends on the different kinds of boundary conditions and on the fact whether the pipe is considered to be inextensible, i.e. the cross-sectional area of the pipe is constant. The equations of motion are derived via Lagrangian equations and Hamilton’s principle. These systems are non-conservative, and the amount of energy carried in and out by the flow appears in the model.
It is well-known, that intricate stability problems arise when the flow pulsates and the corresponding mathematical model, a system of ordinary or partial differential equations, becomes time-periodic. There are several standard techniques, like perturbation method, harmonic balance, finite difference, etc., to analyze these models. The method which constructs the state transition matrix used in Floquet theory in terms of the shifted Chebyshev polynomials of the first kind is especially effective for stability analysis of large systems. The implementation of this method using computer algebra enables us to obtain more accurate results and to investigate more complex models. The stability charts are created with respect to three important parameters: the forcing frequency ω, the perturbation amplitude υ and the mean flow velocity U.
Effect of Oil on the Dynamics of Compressor Suction Valve
Authors: Khalifa H. Ezzat , Liu Xin 
Published: February 2021

Abstract
The presence of oil on the suction valve of a reciprocating compressor has long been known to be responsible for the so-called valve stiction phenomenon. With stiction, the opening of the valve is delayed until later in the suction stroke, which results in a reduction in volumetric efficiency and increases the probability of valve failure. In this paper, a model is presented for analyzing the dynamic behavior of a round reed valve in the presence of oil. It is shown that the primary reason for stiction is the viscous force arising from dilating the oil film between the valve and its seat. This dilation takes place as the cylinder pressure on one side of the valve reed falls below the suction pressure in the intake plenum upstream of the valve. The viscous force delays the valve opening until later in the suction stroke. Because the film dilation resistance is directly proportional to the oil viscosity and decreases rapidly as the film thickens, the film eventually breaks and the valve begins to accelerate rapidly until it impacts the valve stop. The delayed rapid release of the valve and the associated impact are shown to subject the valve to much higher forces than would be experienced without the effect of stiction. The relative effect of oil viscosity and valve/seat contact area on valve force is presented for a representative reciprocating compressor equipped with suction valves.
Modification of the Craig-Bampton CMS Procedure for General Systems
Authors: de Kraker Bram , van Campen Dick H. 
Published: February 2021

Abstract
In this paper the Craig-Bampton CMS procedure for the reduction and successive coupling of undamped structural subsystems with symmetric system matrices will be modified for the case of general damping and nonsymmetric matrices. This leads to a Ritz-transformation matrix based on left- and right static and dynamic modes (complex vectors). The physical meaning of these modes will be illustrated and two examples (a damped beam system and a rotor-system with gyroscopy and a cross-coupling bearing model) will be presented and discussed showing the potential of this extension of the Craig-Bampton procedure.
Levitation and Torque Control of PM Synchronous and Induction Type Bearingless Motor
Authors: Okada Yohji , Miyamoto Shigenobu , Ueno Satoshi , Ohishi Tetsuo , Tan C. C. 
Published: February 2021

Abstract
General solution of levitation control applicable to PM synchronous and induction type rotating motor is presented. It is intended for a single rotor to have both functions of magnetic bearing and rotating motor. The rotational control is achieved with the traditional P pole magnetic flux, while the radial force is controlled with either P+2 or P−2 pole magnetic flux in the stator. In the previous work, the proposed general theory of levitated motor is successfully confirmed with no load experiments.
In this paper, the load capability of the levitated motor is tested using a horizontal type experimental setup. The stator has 8 concentrated wound electromagnets, each of which is controlled individually by a DSP and power amplifier. The radial load is the gravity of the rotor, while the produced rotating torque is measured with a noncontact variable torque load system. The results obtained are discussed in detail.
Analysis of Fabricated Gear Wheels Using Cyclic Symmetry in a PC Environment
Authors: Ramamurti V. , Bhattacharya A. , Manjula S. 
Published: February 2021

Abstract
A computer aided analysis of a heavy duty fabricated gear wheel is presented. The concept of CYCLIC SYMMETRY and the SKYLINE APPROACH are exploited to reduce the computer memory and time. Static and Eigen value analyses are conducted. This is followed by a Quasi Static analysis which gives an idea of the Dynamic behaviour of the gear wheel. The emphasis has been on the use of the PC for solving this industrial problem.
Thermally Induced Synchronous Instability of a Radial Inflow Overhung Turbine: Part I
Authors: Faulkner H. B. , Strong W. F. , Kirk R. G. 
Published: February 2021

Abstract
This paper is in two parts, and concerns the lateral dynamics of a large turbocharger rotor with overhung wheels. Initial rotor dynamic analysis indicated no excessive motion in the operating speed range. However, testing showed excessive motion, which was initially traced to the radial-inflow turbine wheel becoming loose on the shaft, due to transient differential thermal expansion in the wheel on startup. The attachment of the wheel was modified to eliminate this problem. The discussion up to this point is in Part I of the paper, and the remainder is in Part II. The wheel attachment modification extended the range of satisfactory operation upward considerably, but excessive lateral motion was again encountered near the upper end of the operating speed range. This behavior was traced to thermal bowing of the shaft at the turbine end, known as the Morton Effect. The turbine end bearing was modified to eliminate this problem, and satisfactory operation was then achieved throughout the operating speed range.
Coriolis Effect on Mode Localization in a Rotating Bladed Disk
Authors: Kuang J. H. , Huang B. W. 
Published: February 2021

Abstract
An investigation of the speed effect, i.e., the effects of centrifugal force and coriolis force, on the mode localization of a mistuned blade-disk is presented in this paper. A disk comprising of periodically shrouded blades is used to simulate the weakly coupled periodic structure. Galerkin method is employed to derive the mode localization equations of the mistuned system with the consideration of coriolis force. The blades are approximated as cantilever beams, and five axial and lateral modes of each blade are used to present the dynamic behavior of the system. Ten modal coordinates have been considered for each blade. The effects of coriolis force and the magnitude of disorder on the localization phenomenon of a rotating blade-disk system were investigated numerically. Numerical results obtained herein indicate that the coriolis force may enhance the localization phenomenon.
Analysis and Synthesis of Dynamic Response of a Flexibly Coupled Rotor Assembly
Authors: Chaika Valdas 
Published: February 2021

Abstract
Torsional vibration of two flexibly coupled reciprocating machines is investigated. The rotors of the machines are connected by elastic couplings of several types. The system is excited by a harmonic torque. The excitation frequency is proportional to the rotational speed which varies within a wide range. The motion of the system is described by nonlinear ordinary differential equations. These are linearized for the specific case of the rotor assembly design. Applying impedance functions, a closed-form solution of the equations of motion is derived. Three different cases of the system response are analyzed in the frequency domain. The passive vibration control of the rotor assembly using the centrifugal coupling is investigated. An analytical synthesis technique of the coupling parameters is devised.
Modeling and Analysis of Spinning Disk-Spindle Vibration
Authors: Parker Robert G. 
Published: February 2021

Abstract
This work develops the equations of motion for a spinning disk-spindle system. Furthermore, a formulation of the governing equations in terms of extended operators reveals the classical gyroscopic nature of the system. The disk and spindle are modeled as elastic continua coupled by a rigid clamp. System kinematics and dynamics are derived for steady rotation about the spindle axis. The analytical model consists of three partial differential equations for the disk and spindle vibration coupled by four dynamic momentum balances for the clamp translation and rotation. The inherent structure of the system is clarified with the definition of extended operators that collect the component equations into a compact analytical form. The extended operators are easily identified as the classical inertia, elastic bending stiffness, gyroscopic, and rotational stiffness operators. These extended operators possess the symmetry and definiteness characteristics that define gyroscopic continua. Consequently, classical methods for gyroscopic systems are readily applied to disk-spindle systems. The disk-spindle eigensolution, closed-form modal analysis, and discretization procedures that follow naturally from the structured formulation are discussed.