bluuebunny/crossref_metadata_2025_split huggingface dataset:
Global System Optimization Using Hierarchical Genetic Algorithms Based on Decision-Making Components
Authors: Yoshimura Masataka , Izui Kazuhiro 
Published: November 2020

Abstract
The efficient, optimized manufacture of sophisticated products largely depends upon a globally optimized design and manufacturing solution. Ideally, the decision-making tools independently used within various enterprise divisions, such as design and manufacturing, should be integrated, and all decisions made should take into account the goal of global optimization of the entire system. This paper proposes an integrated global optimization technique especially suited to systems consisting of multiple divisions. Each division’s decision-making tools are transformed into components, the interrelationships of these components and other decision variables are classified, and an optimization problem is formulated based on these classifications. The obtained optimization problem is constructed from hierarchically structured decision variables, and the optimization problem is represented by hierarchical genes. Finally, to achieve a globally optimal solution, a hybrid optimization method is demonstrated, that uses a combination of hierarchical genetic algorithms in concert with the optimization methods attached to divisional decision-making components.
Gradation of Planar Mechanism Structures for Robot Arms Based on Their Structural Error Performance
Authors: Pathapati V. V. N. R. Prasad Raju , Rao A. C. 
Published: November 2020

Abstract
Robot arms which received greater attention in the recent past are open chain linkages. Each joint in these robot arms, is actuated independently. While possessing many advantages such as large workspace and maneuverability, they do suffer from disadvantages like less rigidity, accumulation of mechanical errors from shoulder to end effector, control problems etc. The alternative to the open chain robot arms is the in-parallel actuator arrangement often referred to as the platform-type whose successful application is reported by many investigators. Multi-degree-of-freedom Mechanisms are now receiving active consideration for application as platform type robots. In fact in the literature, a number of distinct multi degree of freedom planar linkage mechanisms are available and all of them can be considered as platform type Robots. In this paper numerical measures are proposed to compare all the distinct planar linkage mechanisms at the conceptual stage of design in the category of 9 link, 2 degree of freedom and 10 link, 3 degree of freedom, from the view point of structural error performance. The proposed method is based on the deployment of design parameters in different topological features of the chain Viz., links, Joints and loops.
Derivation of Analytical Expressions for Calculation of AGMA Geometry Factor J for External Spur Gears
Authors: Arikan M. A. Sahir 
Published: November 2020

Abstract
Analytical expressions for calculation of AGMA geometry factor J are derived for external spur gears. Thus, it is made possible to evaluate the J factor easily and with minimum process time for computerized gear analysis and design applications. A computer program is developed to demonstrate the usage of the derived expressions.
Predicting Change Propagation in Complex Design
Authors: Clarkson P. John , Simons Caroline , Eckert Claudia 
Published: November 2020

Abstract
In redesign and design for customization, products are changed. During this process a change to one part of the product will, in most cases, result in changes to other parts. The accurate prediction of this change propagation provides a significant challenge in the management of redesign and customization. This paper reports on an analysis of change behavior based on a case study in GKN Westland Helicopters of rotorcraft design; the development of mathematical models to predict the risk of change propagation in terms of likelihood and impact of change; and the development of a prototype computer support tool.
Engineering Design in New Zealand: Introducing Internet Based Design at Canterbury
Authors: Gooch Shayne , Hales Crispin , Raine John 
Published: November 2020

Abstract
In this paper it is proposed that more emphasis be placed on promoting an entrepreneurial spirit amongst undergraduate students in their final year of study. This is to be achieved through an updated approach to design teaching and by setting projects that have good commercial viability. The aim is to produce graduate engineers with exceptional design and communication skills that they can market competitively around the globe.
Wavelet Transform of Sound Signal in Fluid-Filled Viscoelastic Pipes
Authors: Prek Matjaz 
Published: November 2020

Abstract
In viscoelastic pipes, where the material properties depends on a complex bulk modulus as well as on a complex shear modulus, the sound field within the fluid is affected. Therefore, the dispersion of flexural waves occurs in the pipe, while the speed of flexural waves decreases due to the coupled fluid mass. Coupling between the pipe wall and the fluid as decreases the sound speed in the fluid. Likewise, the speed of sound in fluid is frequency-dependent, just as the group velocity of bending waves depends on the frequency. Wavelet transform of non-stationary sound signal was used to identify the frequency-dependent fluid sound speed. A time-frequency map, constructed by plotting the wavelet coefficient against the translation and scale parameters, shows an alteration in the low frequency waves. The so called “fluid mode” and “pipe mode” resonant frequencies are also clearly evident. Lastly, the impact of different pipe wall material properties is also shown. Wavelet analysis of the measured impulse response of a fluid-filled viscoelastic pipe provides useful tool for investigating its acoustical properties.
Auto-Balance Anisotropic Mounted Rotors
Authors: Wettergren Håkan L. 
Published: November 2020

Abstract
By using balancing balls constrained to move in a circular groove filled with oil, it is possible to reduce, under certain circumstances, the vibration of rotating machinery.
The critical ball-damping ratio is highest just above the natural frequency, after which it rapidly decreases. Consequently, since the interval between instability and critical damping is quite small, the ball damping should be as small as possible without getting too close to the instability threshold. If the rotational frequency is lower than the first eigenfrequency the balls stay together near 0°. Passing the first critical speed the balls almost immediately find the stable position.
Just before the second critical speed, the balls cannot find a steady-state position but simply rotate in the circular groove. Prior to that, the balls find another stable position, which is different from the one that eliminates the mass unbalance.
Active Mass Auto-Balancing System for Centrifuge Rotor Providing an Artificial Gravity in Space
Authors: Ohtomi Koichi , Otsuki Fumio , Uematsu Hirohiko , Nakamura Yasuhiro , Chida Yuichi , Nishimura Osamu , Okamura Ryo 
Published: November 2020

Abstract
The Centrifuge Rotor (CR) is an artificial gravity generator, which is aiming at launch in 2006 as a portion of the life science experimental facility of the International Space Station (ISS). The CR rotates habitats located radially around the axis and generates centrifugal force, imposing artificial gravity of arbitrary magnitude up to 22.0 m/s2 (about 2.2 g) on the specimens housed in the habitats. The imbalance is caused by the asymmetry of two habitats opposite each other, which brings about change in the mass of the habitats as well as the quasi-static change of the CG of plants and fluids and the dynamic rodent motions in the habitats. The active mass Auto-Balancing System (ABS) is provided for automatic canceling of the above-mentioned imbalance of the rotor. This paper presents the concept and the test results of the ABS.
Pattern Formation in a Parametrically-Excited P.D.E.
Authors: Stubna Michael D. , Rand Richard H. 
Published: November 2020

Abstract
We investigate the dynamics of the parametrically-excited P.D.E.(1)∂2u∂t2-c2(∂2u∂x2+∂2u∂y2)+εβ∂u∂t+(∂+εγcos⁡t)u=εαu3 with Neumann boundary conditions on a rectangular region:∂u∂x=0forx=0,π and ∂u∂y=0fory=0,πμ where 0 &lt; μ ≤ 1. Our approach involves expanding u(x, y, t) in a 3-term Fourier series truncation:(2)u=f0(t)+f1(t)cos⁡x+f2(t)cos⁡μy By substituting (2) into (1) we obtain a system of 3 coupled nonlinear Mathieu equations which we analyze using averaging in the neighborhood of 2 : 1 resonance.
By varying the parameters c and δ we obtain bifurcation curves which divide the cδ-plane into more than forty regions, each containing a distinct slow flow. Individual regions are found to differ from one another with respect to such features as the number and character of slow flow equilibria, and the presence or absence of a limit cycle. When interpreted in the original variable u, these regions account for a variety of patterns which may be classified as stationary, traveling or rotating.
This type of behavior is comparable to various experimental observations made by other investigators on vertically driven fluids or sand.
Optimal Control Design of a Bimorph Optical Beam Deflector
Authors: Chao Chang-Po , Huang Jeng-Sheng , Yung Ching-Lung Ou , Fung Rong-Fong 
Published: November 2020

Abstract
The optical beam deflector is composed of two piezoelectric layers, one sandwiched brass layer in the middle with both ends clamped and a mirror attached to the upper surface of the top piezoelectric layer in the central position. This structure is designed to deflect the mirror to a certain angular position by applying external voltage supply to piezo-layers. This study proposes an optimal angular position control scheme of the attached mirror. The governing partial differential equations are first derived for the ensuing analysis and control design, which is followed by the establishment of finite element model in ten nodes specified at some longitudinal points of the optical beam deflector. In order to achieve a faster convergent rate for the deflector to reach the desired angular position, the optimal control of LQ regulator with final states fixed is employed to explore the possibility of shorter transient response and less cost of control effort and states. The optimal feedback control is obtained based on solving a dynamic Riccati equation backward in time. The numerical simulation results are finally provided to validate the theoretical control design.
An Investigation of a Rocking-Sliding Block
Authors: Virgin L. N. , Aldemir U. , Gavin H. P. , Nichols J. M. , Plaut R. H. 
Published: November 2020

Abstract
The short end of a rigid rectangular block with a 2:1 aspect ratio is placed on a flat horizontal surface. The surface exhibits a horizontal harmonic motion, and two-dimensional motions of the block are investigated numerically and experimentally. A variety of modes of behavior are possible, and, when viewed from the side, attention is focused on (a) rocking of the block about either bottom corner or (b) sliding while rocking about one of those corners. Different periodic or erratic rocking-sliding responses are observed, with overturning being one of the possible outcomes. This system has relevance to a number of practical applications, especially in the context of earthquake engineering.
The experiment consists of two aluminum blocks separated by a heavy steel cylinder. It is mounted on a shake table that oscillates harmonically in the horizontal direction. Data are acquired using image video processing with a number of targets mounted on the block face. Two guides are used to ensure that the motion remains in the vertical plane. Reasonable qualitative agreement between simulations and experimental data is achieved, especially when viewed within the context of highly nonlinear systems and their inherent sensitivity. This work may be considered as an extension to our previous work (Fielder et al., 1997), with the addition of sliding being the major new ingredient.
Feasibility of Two-Dimensional Control for Ship-Mounted Cranes
Authors: Abdel-Rahman Eihab M. , Nayfeh Ali H. 
Published: November 2020

Abstract
We test the feasibility of employing an exclusively planar control effort to suppress unsafe ship-mounted crane pendulations induced by sea motions. The new crane configuration, designed to apply the control effort, is modeled and the proposed control effort, employing Coulomb friction and viscous damping, is applied. The three-dimensional nonlinear dynamics of the crane is then investigated.
The new crane configuration, dubbed Maryland Rigging, transforms a crane from a single spherical pendulum to a double pendulum system. The upper pendulum, a pulley riding on a cable suspended from the boom, is constrained to move over an ellipsoid. The major axis of the ellipsoid is the boom and the foci are the two points at which the riding cable attaches to it. The lower pendulum, the payload suspended by a cable from the pulley, continues to act as a spherical pendulum. Due to the geometry of the ellipsoid, the natural frequencies of the crane in the plane of the boom (in-plane) are almost equal to the out-of-plane natural frequencies.
The model is used to examine the response of a Maryland rigged crane to direct, in-plane, harmonic forcing. The frequency of the excitation is set almost equal to the crane’s lowest natural frequency. It is found that under this excitation and due to the one-to-one internal resonance between the lowest in-plane and out-of-plane natural frequencies, significant out-of-plane motions are induced by applying a purely in-plane forcing. Thus an in-plane control mechanism is not adequate for safe operation of the crane. To guarantee safe operation of a ship-mounted crane, one must apply both in-plane and out-of-plane control efforts.
Effect of Piezoceramic Hysteresis in Passive and Hybrid Structural Acoustic Control
Authors: Ozer M. Bulent , Royston Thomas J. 
Published: November 2020

Abstract
Structural acoustic control via passive and hybrid electrical shunting of a piezoceramic wafer bonded onto the surface of a simply supported plate is investigated with emphasis on modeling and understanding the effect of piezoceramic nonlinearity on system performance. A nonlinear rate-independent finite-dimension Ishlinskii hysteresis model is experimentally identified for the PZT wafer by itself and then integrated into the coupled dynamic equations of the overall system consisting of the plate and electrically shunted PZT wafer. This model is then used to investigate the impact of PZT hysteresis on its structural acoustic control performance in passive and hybrid scenarios. A multi-term describing function representation of the Ishlinskii hysteresis model is formulated to aid in computational studies.
Identifying Coulomb and Viscous Friction in Forced Dual-Damped Oscillators
Authors: Liang J.-W. , Feeny B. F. 
Published: November 2020

Abstract
This paper presents a method for estimating Coulomb and viscous friction coefficients from responses of an harmonically excited dual-damped oscillator. The identification method is based on analytical solutions of non-sticking responses excited near the natural frequency. It is applicable if the damping ratio of the viscous component can be considered small. The Coulomb and viscous friction parameters can be extracted from two or more input-output amplitude pairs at resonance. The method is tested numerically and experimentally. Experimental results are cross checked with estimations from free-vibration decrements and also from friction measurements.
Stability of Motorcycles Under Acceleration and Braking
Authors: Limebeer David J. N. , Evangelou Simos , Sharp Robin S. 
Published: November 2020

Abstract
A comprehensive study of the effects of acceleration and braking on motorcycle stability is presented. This work is based on a modified version of the dynamic model that was first presented in (Sharp & Limebeer, 2000), and is thought to be the most comprehensive motorcycle dynamic model in the public domain. Extensive use is made of both nonlinear and linearized models. The models are written in LISP and make use of the multibody modelling package AUTOSIM (Autosim 2.5+, 1998). There is novelty in the way in which control systems have been used to control the motorcycle drive and braking systems in order that the machine maintains desired rates of acceleration and deceleration.
The results show that the wobble mode of a motorcycle is significantly destabilized when the machine is descending an incline, or braking on a level surface. Conversely, the damping of the wobble mode is substantially increased when the machine is ascending an incline at constant speed, or accelerating on a level surface. This probably accounts for the pleasing stable “feel” of the machine under firm acceleration.
Except at very low speeds, inclines, acceleration and deceleration appears to have very little effect on the damping or frequency of the weave mode. Nonlinear simulation have quantified the known difficulties to do with rear tyre adhesion in heavy braking situations that are dominated by rear wheel braking.
Analysis of Load Dependent Dynamic Transmission Error Response of Gears With Random Pitch Error
Authors: Márialigeti János , Lovas László 
Published: November 2020

Abstract
For more realistic gear dynamic behaviour predictions, detailed gear dynamic models are needed, allowing taking into consideration the most important influencing factors. System model is presented, based on the separate handling of individual tooth pairs, with their specific profile corrections, manufacturing errors etc. Further on, non-linear single tooth pair force-deflection curve is considered, resulting in load dependent eigenfrequency characteristics. Simulation results are presented for gears with randomly distributed pitch errors. Gears with normal tooth profile and with tip relief are compared, and vibration response characteristics are analysed based on Fourier analysis of simulated transmission error response curves.
Study on Nonlinear Dynamic Characters of Rotor-Bearing System
Authors: Xia Songbo , Zhang Xinjiang , Wu Xinhua , Xu Genfa 
Published: November 2020

Abstract
The stability of a rigid Jeffcott rotor system based on short-bearing model is study in a relatively wide parameter range using the Poincaré maps and numerical integral method. The results of calculation show that the period doubling bifurcation, quasi-periodic and chaos motions may be occurred. In some typical parameter regions the bifurcation diagrams, phase portrait, Poincaré maps and the frequency spectrums of the system are acquired with numerical integral method. They demonstrate some motion state of the system. The fractal dimension concept is used to determine whether the system is in a state of chaos motion. The analysis result of this paper provides the theoretical bases for qualitatively controlling the stable operating states of rotors.
Single-Bagged Air Spring’s Parameter Calculation
Authors: Lou Jingjun , Zhu Shijian , Qian Weijian , He Lin 
Published: November 2020

Abstract
This paper sets up a dynamic model of a single-bagged air spring with an auxiliary air chamber on the basis of the polytrope process state equation. The calculation formulas for stiffness and natural frequency are derived. Factors affecting damping coefficient and natural frequency are analyzed.
Nonlinear Parametric Vibrations of an Elastic Structure With a Cylindrical Liquid Container (in the Case of an Anti-Symmetric Sloshing Mode)
Authors: Ikeda Takashi , Murakami Shin 
Published: November 2020

Abstract
The nonlinear-coupled vibrations of an elastic structure and liquid sloshing in a cylindrical container are investigated. Since the structure is vertically subjected to a sinusoidal excitation, the behavior of the liquid surface is governed by a kind of the Mathieu equation. Modal equations governing the coupled motions are derived, when the natural frequency of the structure is equal to twice the natural frequency of an anti-symmetric mode of sloshing. The theoretical resonance curves are also presented by using an FFT analysis and the improved harmonic balance method. The influences of a liquid level and a detuning parameter on the theoretical resonance curves are shown. A small deviation of the tuning condition can cause amplitude-modulated motions and separate the occurrence region of the coupled vibration into two regions. In the experiments, the theoretical resonance curves were qualitatively in agreement with the experimental data. In addition, amplitude-modulated motions were observed.
Control of a Buckled Beam Subjected to a Compressive Force
Authors: Yabuno Hiroshi , Ando Kazuya , Aoshima Nobuharu 
Published: November 2020

Abstract
In this paper, we deal with a stabilization control for the buckled beam subjected to a compressive force. It is easily predicted that by applying a restoring force to the beam (P control), which is proportional to the deflection, the critical compressive force for the buckling is increased. However it is theoretically and experimentally clarified in our former study that in the neighborhood of the critical point, the effect of Coulomb friction at the supporting points is relatively increased even if it is very slight. It follows that the beam cannot be stabilized to the trivial steady state only by using the position feedback control and also velocity feedback. In this paper, we propose a stabilization control method of the beam to the trivial steady state by the aid of disturbance observer. Furthermore, the validity of the theoretically proposed method is experimentally confirmed.
Cyclostationary Analysis of Rolling Element Bearing Vibration Signals
Authors: Glossiotis George N. , Antoniadis Ioannis A. 
Published: November 2020

Abstract
Vibration signals resulting from rolling element bearings present a rich content of physical information, the proper analysis of which can lead among others to the identification of possible faults. Traditionally, this analysis is performed by the use of signal processing methods, which assume statistically stationary signal features. The paper proposes an alternative framework for analyzing bearing vibration signals, based on cyclostationary analysis. This framework, being able to model additionally signals with periodically varying statistics, is better able to exhibit the underlying physical concepts of the modulation mechanism, present in the vibration response of bearings. The basic concepts of the approach are demonstrated both in illustrative simulation results, as well as in experimental results and industrial measurements for two different types of bearing faults.