bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Consideration of Applying QFD to Concurrent Engineering Processes of Automobile Development
Authors: Tsuda Yasuhisa 
Published: March 2021

Abstract
As a tool to present the systematic application of QFD to product development, a “two-storied quality chart” model is conceived which the project team prepares with the support of functional departments. To consider the progress of time, this chart is further developed to contain two parts, one to be provided for the new development and the other relying on data accumulated in the past. Furthermore a “parallel flow quality chart” is conceived, considering the job sharing between the project team and functional departments. By means of these concept models it is made clear that the development activities pushed forward simultaneously by many departments can be separately treated as individual quality deployment in each department. In this way the application of QFD to a complicated product development, in which many departments are involved, is made much easier.
A Flexible, Interactive Integration Architecture for Extraction of CAPP Information From CAD
Authors: Hayes C. C. 
Published: March 2021

Abstract
This paper describes CHAMP, a conceptual architecture designed to support the task of passing information from computer-aided design systems to computer-aided process planning systems.1 Current integration systems are lacking in the flexibility of both their information-exchange mechanisms and in their control structures. The result is a sacrifice in the efficiency of solutions produced. The proposed architecture is based on models of human process planning, and aims to improve the effectiveness of CAD/CAPP integration by providing more flexible communications and control structures through shared blackboards, and by providing a mechanism for reasoning about intermediate solution states. The architecture is intended to summarize the current understanding of the CAD/CAPP integration task and to elucidate areas where further research is required.
Nonstationary Response of a Two-Degrees-of-Freedom Nonlinear Ship Model Under Modulated Excitation
Authors: Pan Ruigui , Davies Huw G. 
Published: March 2021

Abstract
Nonstationary response of a two-degrees-of-freedom system with quadratic coupling under a time varying modulated amplitude sinusoidal excitation is studied. The nonlinearly coupled pitch and roll ship model is based on Nayfeh, Mook and Marshall’s work for the case of stationary excitation. The ship model has a 2:1 internal resonance and is excited near the resonance of the pitch mode. The modulated excitation (F0 + F1 cos ωt) cosQt is used to model a narrow band sea-wave excitation. The response demonstrates a variety of bifurcations, loss of stability, and chaos phenomena that are not present in the stationary case. We consider here the periodically modulated response. Chaotic response of the system is discussed in a separate paper.
Several approximate solutions, under both small and large modulating amplitudes F1, are obtained and compared with the exact one. The stability of an exact solution with one mode having zero amplitude is studied. Loss of stability in this case involves either a rapid transition from one of two stable (in the stationary sense) branches to another, or a period doubling bifurcation. From Floquet theory, various stability boundary diagrams are obtained in F1 and F0 parameter space which can be used to predict the various transition phenomena and the period-2 bifurcations. The study shows that both the modulation parameters F1 and ω (the modulating frequency) have great effect on the stability boundaries. Because of the modulation, the stable area is greatly expanded, and the stationary bifurcation point can be exceeded without loss of stability. Decreasing ω can make the stability boundary very complicated. For very small ω the response can make periodic transitions between the two (pseudo) stable solutions.
The Applicability of Fuzzy Control for Flexible Mechanisms
Authors: Beale David G. , Lee Shyr Wen 
Published: March 2021

Abstract
The nonlinear nature of high speed, flexible rod mechanisms has been previously confirmed, both experimentally and analytically. Therefore, sound control system design of flexible mechanisms must necessarily be based on nonlinear control. Active control via fuzzy logic is assessed as a means to suppress the elastic transverse bending vibration of a flexible rod of a slider crank mechanism of a slider crank mechanism. Several pairs of piezoelectric elements are used to provide the control action. Sensor output of deflection is fed to the fuzzy controller, which determines the voltage input to the actuator. A three mode approximation is utilized in the simulation study. Computer simulation shows that fuzzy control can be used to suppress bending vibrations at high speeds.
Effects of Flexible Supports and Gyroscopic Moments on Passage of a Cracked Shaft Through a Critical Speed
Authors: Suherman Surjani , Plaut Raymond H. 
Published: March 2021

Abstract
The motion of a cracked shaft with a rigid disk is analyzed as the system is accelerated or decelerated past the lowest critical speed. New features are the inclusion of flexible supports at the ends of the shaft and the gyroscopic effects of the disk. The supports are modeled with elastic springs and dashpots. Eccentricity of the disk, gravitational forces, and internal and external damping are also included. The shaft contains a single transverse crack that is assumed to be either completely open or completely closed at any given time, depending on the curvature of the shaft at the cross section containing the crack. The maximum response is computed numerically, and the influence of the gyroscopic moments and the spring and damping coefficients at the supports is investigated.
Two-to-One Internal Resonances in Buckled Beams
Authors: Kreider Wayne , Nayfeh Ali H. , Chin Char-Ming 
Published: March 2021

Abstract
The vibrations of buckled beams with two-to-one internal resonances (ω2 ≈ 2ω1) about a static buckled position are analyzed. General boundary conditions and harmonic excitations (frequency Ω) in both the transverse and axial directions are considered. The analysis assumes a unimodal static buckled deflection, considers quadratic nonlinearities only, and determines the amplitude and phase modulation equations via the method of multiple scales. The following specific cases are treated: Ω ≈ 2ω2, Ω ≈ ω1 + ω2, and Ω ≈ ω1. From the modulation equations for a primary resonance of the second mode (i.e., Ω ≈ ω2), one-mode and two-mode stable equilibrium solutions are found in addition to dynamic solutions caused by Hopf bifurcations. In the region of dynamic solutions, a variety of phenomena are documented, including period-doubling bifurcations, intermittency, chaos, and crises.
Chaotic Amplitude Dynamics for Parametrically Excited Systems With Quadratic Nonlinearities
Authors: Banerjee Bappaditya , Bajaj Anil K. 
Published: March 2021

Abstract
Dynamical systems with two degrees-of-freedom, with quadratic nonlinearities and parametric excitations are studied in this analysis. The 1:2 superharmonic internal resonance case is analyzed. The method of harmonic balance is used to obtain a set of four first-order amplitude equations that govern the dynamics of the first-order approximation of the response. An analytical technique, based on Melnikov’s method is used to predict the parameter range for which chaotic dynamics exist in the undamped averaged system. Numerical studies show that chaotic responses are quite common in these quadratic systems and chaotic responses occur even in presence of damping.
Estimating Ljapunov-Exponents Using the Generalized Cell Mapping Method
Authors: Schaub Swen , Schiehlen Werner 
Published: March 2021

Abstract
Ljapunov-Exponents are widely used to characterize the local stability of dynamical systems. On the other hand, Cell Mapping methods provide an effective numerical tool for global study by a probabilistic description of the time evolution. Using this description together with powerful interpolation techniques, an iterative method for global stability analysis with estimated Ljapunov-Exponents for all coexisting attractors of nonlinear dynamical systems is presented.
Numerical Formulation of Nonlinear Vibrations of Elastically-Constrained Rotating Disks
Authors: Yang Longxiang , Hutton Stanley G. 
Published: March 2021

Abstract
An analysis of nonlinear vibrations of an elastically-constrained rotating disk is developed. The equations of motion, which are two coupled nonlinear partial differential equations corresponding to the transverse force equilibrium and to the deformation compatibility, are first developed by using von Karman thin plate theory. Then the stress function is analytically solved from the compatibility equation by assuming a multi-mode transverse displacement field. Galerkin’s method is applied to transform the force equilibrium equation into a set of coupled nonlinear ordinary differential equations in terms of time functions. Finally, numerical integration is used to solve the time governing equations, and the effects of nonlinearity on the vibrations of a rotating disk are discussed.
A Nonlinear Normal Mode Approach for Studying Waves in Nonlinear Monocoupled Periodic Systems
Authors: Vakakis A. F. , King M. E. 
Published: March 2021

Abstract
The free dynamics of a mono-coupled layered nonlinear periodic system of infinite extent is analyzed. It is shown that, in analogy to linear theory, the system possesses nonlinear attenuation and propagation zones (AZs and PZs) in the frequency domain. Responses in AZs correspond to standing waves with spatially attenuating, or expanding envelopes, and are synchronous motions of all points of the periodic system. These motions are analytically examined by employing the notion of “nonlinear normal mode,” thereby reducing the response problem to the solution of an infinite set of singular nonlinear partial differential equations. An asymptotic methodology is developed to solve this set. Numerical computations are carried out to complement the analytical findings. The methodology developed in this work can be extended to investigate synchronous attenuating motions of multi-coupled nonlinear periodic systems.
The Dynamics of Viscoelastic Links in Mechanisms
Authors: Buculei Mihai I. , Marghitu Dan B. 
Published: March 2021

Abstract
The main objective of this study is to develop an analytical model that incorporates the effect of the general motion on the vibration of elastic elements in kinematic mechanisms. Equations for the translational and rotational motions of the links are developed applying Hamilton’s principle. Kinetic energy that is required for the application of this principle has been derived by utilizing a generalized velocity field theory for elastic solids. This approach provides means to include the inertia terms directly in the equations of motion. Effects such as centrifugal stiffening and vibrations induced by Coriolis forces are accommodated automatically, rather than with the aid of ad hoc provisions. We use Alfrey and Lee analogy to solve the dynamic problem of viscoelasticity.
Safety Enhancement of Hysteretic Structures Through Active Control
Authors: Li Peng , Aug Alfredo H.-S. 
Published: March 2021

Abstract
A new control algorithm is developed for hysteretic structures. The performance function is chosen to minimize the structural damage. Numerical examples are presented to show the effectiveness of the proposed control algorithm. It is noted that the algorithm could improve the control efficiency in terms of reducing the required total control energy or maximum control forces without sacrificing the structural safety.
Stabilization by Random Vibration
Authors: Wihstutz Volker 
Published: March 2021

Abstract
We consider the control system ẋ = Ax + Bu with stochastic mean zero high gain feedback control u. The classes of stochastic processes which can stabilize the trivial solution x = 0 depend on the rank of B. For rank B = 1 we characterize, in particular, the class of noise which stabilizes the originally unstable equilibrium of the linearized inverted pendulum.
Dynamic Reliability of Nonlinear Systems Under Random Excitation
Authors: Colonius Fritz , Häckl Gerhard , Kliemann Wolfgang 
Published: March 2021

Abstract
Reliability theory analyzes failure phenomena in systems, leading to maintenance and replacement schedules as well as risk assessment and other topics. Dynamic reliability takes into account the (possibly nonlinear) dynamics of the system and of the random excitation that may lead to failure. It is shown, how some of the concepts of reliability theory can be interpreted in the dynamical systems context. Analytical results are derived for failure probabilities, for life time distributions, asymptotic damage accumulation rates, and other relevant concepts. The Takens-Bogdanov oscillator and a model for ship roll motion are analyzed in detail, together with a thorough description of the numerical methods that are available for dynamic reliability studies.
Evaluation of Surface Vibrations in the Low and High Frequency Domain
Authors: Fischer Peter , Pradlwarter Helmut J. , Schuëller Gerhart I. 
Published: March 2021

Abstract
The frequency domain of many problems in structural dynamics encompasses a wide range, covering nearly static behavior up to vibration flow characteristics similar to heat transfer. This work presents an uniform approach for low and high frequency vibration analysis, which is based on Finite Element modeling of the structure. Vibrations in the low frequency range are determined by an efficient superposition technique of complex modes, which accounts accurately for any linear damping effect. The modal method is extended to the high frequency domain by applying different levels of averaging to the response and eigenfrequencies and by the introduction of random properties of modeshapes. The high frequency domain is defined by the size of the Finite Elements, i.e. short wave lengths of high frequency modeshapes cannot be represented by the FE-model. The response computation of isolated structures is extended to substructures of complex systems by prescribing stochastic multi-support base excitation at the substructure boundaries. It may be noted, that the presented approach of stochastic high frequency dynamics contains, as special cases, the expressions of the structural response of Statistical Energy Analysis, Bolotin’s integral method and the results of Asymptotic Modal Analysis.
Vibration-Induced Loosening and Tightening of Threaded Fasteners
Authors: Hess Daniel P. 
Published: March 2021

Abstract
Previous analyses of threaded fasteners under vibration are based on static equilibrium conditions with supporting data limited to low frequency loading. Such analyses predict only a net loosening action. This paper presents a dynamic model of a single-bolt assembly with moderate pre-load subjected to axial harmonic vibration. Simulations with this model predict that threaded fasteners can, on the average, loosen or tighten in the presence of vibration; and that the applied vibration, as well as other system parameters, can be tuned so that either action occurs. The model elucidates the nonlinear interaction of friction and vibration of such systems. Measurements from a single-bolt assembly apparatus are presented and compared with the simulations.
Friction-Induced Vibration of Multi-Degree of Freedom Sliding Subsystems
Authors: Rorrer Ronald A. L. 
Published: March 2021

Abstract
The purpose of this investigation is to develop an appropriate model for the friction-induced vibration of a tribological system, where there is at least an order of magnitude difference in the stiffness between the mating subsystems. The significance of this system is that neither system can analytically be considered rigid or aspects of the dynamics that are exhibited experimentally are lost. This leads to the necessity of creating a multi-degree of freedom model, where the multiple degrees of freedom are distributed between the two systems. Experiments have shown that both subsystems contribute to the dynamical response. The modeling starts with the simplest system model, in terms of degrees of freedom, and then progresses to the level required to demonstrate the experimentally observed behavior. An example of such a system is an elastomer sliding against a steel counterface. It has been observed on a variety of dissimilar test devices (linear and rotational) that the subsequent response contains similar dynamical behavior relative to friction-induced vibration. The striking similarities of the dynamic behavior is demonstrated in the friction(time) response, which is subsequently evidenced in the autospectra of friction with an identifiable characteristic form. Specifically, with the exception of scaling in amplitude and frequency, due to system differences, the autospectrum are contained within a characteristic envelope that is determined by both subsystems. While not specifically attempting to model any particular test device or system, representative values of stiffness and estimated friction (velocity) relationships have been incorporated to lend realism to the models.
Pattern Changes of Time-Shifted Vibration Signals on Wavelet Time-Scale Maps
Authors: Chen Da Jun , Wang Wei Ji 
Published: March 2021

Abstract
As a multi-resolution signal decomposition and analysis technique, the wavelet transforms have been already introduced to vibration signal processing. In this paper, a comparison on the time-scale map analysis is made between the discrete and the continuous wavelet transform. The orthogonal wavelet transform decomposes the vibration signal onto a series of orthogonal wavelet functions and the number of wavelets on one wavelet level is different from those on the other levels. Since the grids are unevenly distributed on the time-scale map, it is shown that a representation pattern of a vibration component on the map may be significantly altered or even be broken down into pieces when the signal has a shift along the time axis. On contrary, there is no such uneven distribution of grids on the continuous wavelet time-scale map, so that the representation pattern of a vibration signal component will not change its shape when the signal component shifts along the time axis. Therefore, the patterns in the continuous wavelet time-scale map are more easily recognised by human visual inspection or computerised automatic diagnosis systems. Using a Gaussian enveloped oscillation wavelet, the wavelet transform is capable of retaining the frequency meaning used in the spectral analysis, while making the interpretation of patterns on the time-scale maps easier.
An Accelerated Retarded Potential Method for Time Dependent Acoustic Wave Scattering
Authors: Abboud Toufic S. , Gharib Joseph M. , Nédélec Jean Claude , Sayah Toni G. 
Published: March 2021

Abstract
We are interested in the numerical approximation of the problem of the scattering of a transient acoustic plane wave by a bounded obstacle in IR2 or IR3, using the boundary integral equation method. In the frequency domain it has been recently developed a boundary finite element method where the mesh size is like O(λ1/3) instead of O(λ) (λ is the wavelength) and where the obstacle is convex. This paper presents the implementation of the idea on the retarted potential representation.
Coupled Finite Element/Boundary Element Method for the Analysis of the Acoustic Scattering From Elastic Structures
Authors: Dubus Bertrand , Lavie Antoine , Decultot Dominique , Maze Gérard 
Published: March 2021

Abstract
Considerable interest has been expressed recently in the scattering of acoustic waves from elastic targets. For structures of arbitrary shapes, the numerical method relying upon a finite element description of the solid part and a boundary element description of the waves propagating in the infinite fluid medium is the most commonly used. This paper presents a coupling between the ATILA finite element code and the EQI boundary element code performed using a solid variable methodology. Results are presented for a thin cylindrical shell bounded by hemispherical endcaps which are insonified at axial and normal incidences. Comparisons are made with measurements of backscattered pressure spectra and angular patterns obtained with the quasi-harmonic MIIR (Method of Isolation and Identification of Resonances). Emphasis is put on post-processing techniques contributing to the interpretation of physical phenomena such as the extraction of resonant mode shapes.
Transient Infinite Elements for Acoustics and Shock
Authors: Cipolla Jeffrey L. 
Published: March 2021

Abstract
Many phenomena in acoustically loaded structural vibrations are better understood in the time domain, particularly transient radiation, shock, and problems involving nonlinearities and bulk structural motion. In addition, the geometric complexity of structures of interest drives the analyst toward domain-discretized solution methods, such as finite elements or finite differences, and large numbers of degrees of freedom. In such methods, efficient numerical enforcement of the Sommerfeld radiation condition in the time domain becomes difficult; although a great many methodologies for doing so have been demonstrated, there seems to exist no consensus on the optimal numerical implementation of this boundary condition in the time domain.
Here, we present theoretical development of several new boundary operators for conventional finite element codes. Each proceeds from successful domain-discretised, projected field-type harmonic solutions, in contrast to boundary integral equation operators or those derived from algebraic functions. We exploit the separable prolate-spheroidal coordinate system, which is sufficiently general for a large variety of problems of naval interest, to obtain finite element-like operators (matrices) for the boundary points. Use of this coordinate system results in element matrices that can be analytically inverse transformed from the frequency to the time domain, using appropriate approximations, without altering the Hilbert space in which the approximate solution resides. The inverse transformation introduces some additional theoretical issues involving time delays and Stieltjes-type integrals, which are easily resolved. In addition, use of element-like boundary operators does not alter the banded structure of the system matrices, which is of enormous importance for efficient solution of large problems.
Results presented here include theoretical derivation of the new “infinite elements”, the approximations for certain problematic frequency-domain terms, resolution of the inversion issues, and element matrices for the boundary operators which introduce no new continuity requirements on the fluid field variable.
Practical Applications of Scale Independent Elements
Authors: Ettouney Mohammed M. , Daddazio Raymond P. , Abboud Najib N. 
Published: March 2021

Abstract
Discrete deterministic methods such as finite elements offer great flexibility in analyzing the dynamic response of vibrating systems. However, these methods can easily grow beyond available computer resources as frequencies of interest grow higher. In this paper we present a new approach for the frequency domain dynamic analysis of structures. A theory is developed for the analysis of systems which are uniform along a single coordinate axis but otherwise arbitrary in geometry and material composition. This approach, termed the Scale Independent Element, is shown to be an accurate, efficient and general method for the analysis of vibrating systems. This technique extends the applicability of discrete deterministic finite element based modeling to higher frequencies and is capable of bridging the gap to frequency regimes where statistical energy methods become applicable.