bluuebunny/crossref_metadata_2025_split huggingface dataset:
Axial Force Stabilization of Transverse Beam Vibration
Authors: Rahn Christopher D. , Mote C. D. 
Published: March 2021

Abstract
An axial force stabilizes the transverse vibration of a beam with translational and rotational boundary springs and arbitrary geometry. The nonlinearly coupled, longitudinal and transverse equations of motion of the beam with axial force control are derived and simplified using a quasistatic assumption. Lyapunov’s direct method and an invariance principle for distributed systems show that an axial damper can asymptotically and simultaneously stabilize all transverse vibration modes. Asymptotic stability is guaranteed if the eigenvalues are simple and nonzero and if there are no internal resonances between coupled modes.
Distributed Orthogonal Filtering of Piezoelectric Shell Actuators
Authors: Tzou H. S. , Zhong J. P. 
Published: March 2021

Abstract
Distributed control of elastic shell continua using spatially distributed piezoelectric actuators is proposed and a generic distributed velocity feedback algorithm with a spatial modal feedback function formulated. The generic distributed modal feedback function is further represented by a gain factor and a spatially distributed orthogonal (mode shape) function to achieve independent modal actuation capability. Based on this principle, distributed piezoelectric actuators can be spatially shaped to emulate the spatial orthogonal actuation of the distributed modal feedback function. Distributed orthogonal shaped modal actuators for ring shells are proposed and their modal actuations demonstrated. Analyses suggested that the primary control action came from the in-plane membrane (circumferential) forces and that contributed by the bending control moment is relatively insignificant for lower natural modes. Control effects due to thickness variation of the ring shell and the actuator are also investigated.
Characterization and Reduction of Reluctance Torque in Permanent Magnet D.C. Motors
Authors: Hwang Sangmoon , Lieu Dennis K. 
Published: March 2021

Abstract
For motors with low speeds and loads, torque pulsation by the reluctance torque is an important source of vibration and control difficulty. In this paper, the magnetic field of a motor is calculated by finite element method and the periodic reluctance torque is determined using Maxwell stress method and time stepping method, and then decomposed using Fourier series expansion. The purpose of this paper is to characterize design parameters on the reluctance torque and to design a permanent magnet motor with a reluctance torque less vulnerable to vibration, without sacrificing the motor performance. The design parameters include stator slot width, permanent magnet slot width, airgap length and magnetization direction. A new design with a less populated frequency spectrum of the reluctance torque is proposed after characterizing individual effect of design parameters. Gradual magnetization, by gradually increasing the thickness of the permanent magnets at edges, yields a smooth shape for the reluctance torque with reduced harmonics.
Free and Forced Vibration of Stepped Levy Plates
Authors: Lee Jinkyo , Bergman Lawrence A. 
Published: March 2021

Abstract
The study of the transverse vibration of thin rectangular plates has been mainly confined to plates of uniform thickness. There are few publications available on the vibration of plates with nonuniform thickness. These plates have application in various fields such as civil engineering and aerospace structures and are often found in high frequency acoustic transducers. Furthermore, it is sometimes possible to achieve minimum weight design of plates by having suitable variations in thickness. For the special case of a plate with two opposite edges simply supported and thickness discontinuities perpendicular to the simply supported edges, an analytical solution is possible using a dynamic flexibility method. Several examples are discussed.
Parametric Studies on Muffler Design With Applications to a Vacuum Pump
Authors: Sridhara B. S. 
Published: March 2021

Abstract
A computer simulation was employed to perform parametric studies on muffler design. Engine exhaust system parameters such as muffler diameter, source-muffler pipe length, number of mufflers, series and parallel installation of mufflers, and the source and termination impedances were considered during the studies. The muffler insertion loss and radiated sound pressure level were predicted for several values of each parameter. An acoustic model consisting of a lumped source-muffler-termination system was used. A scheme was developed using the pressure source model to predict the radiated sound pressure and a simplified expression for the predicted quantity was obtained as a sum of the measured, plane wave and monopole terms. The relationship between the insertion loss and radiated sound pressure level was established for a given set of conditions. A vacuum pump was used as the sound source. An expansion chamber was used as a muffler.
Vibration Analysis of a Partially Covered Double Sandwich Cantilever Beam With Concentrated Mass at the Free End
Authors: Levy C. , Chen Q. 
Published: March 2021

Abstract
The partially covered, sandwich-type cantilever with concentrated mass at the free end is studied. The equations of motion for the system modeled via Euler beam theory are derived and the resonant frequency and loss factor of the system are analyzed. The variations of resonance frequency and system loss factor for different geometrical and physical parameters are also discussed. Variation of these two parameters are found to strongly depend on the geometrical and physical properties of the constraining layers and the mass ratio.
Determination of the Position of Solid/Liquid Interface During Solidification and Melting of Metals With Vibrational Parameters
Authors: Fengquan Wang , Zhenghua Zhu , Shiyu Chen 
Published: March 2021

Abstract
The paper proposes the method to locate the solid / liquid interface with vibrational parameters during solidification for the first time. The sufficient difference in resistance to shear stresses between liquid and solid phases of metals and alloys permits the application of vibrational parameters to locate the interface in real time and in situation during solidification. Based on the solidification theory, continuum mechanics, vibrational modal analysis and sensitivity analysis, the author established the mechanical model and the dynamical equations of typical Bridgman solidifying system, derived the sensitivity of eigenvalues of the Bridgman system to the location of the solid / liquid interface as well as the calculating formulae concerned. The experimental results are quite accordant with those of computed ones.
A Simple Method for Extracting Normal Modes
Authors: Chen S. Y. , Ju M. S. , Tsuei Y. G. 
Published: March 2021

Abstract
A simple method for extracting the normal modes of structures is developed. The frequency response function relation between the complex and the normal modes is derived and a technique is developed to calculate the normal modes from the identified (damped) complex modes. In this method, only the magnitude and phase information at resonant frequencies are needed for extracting the normal mode shapes. A numerical example is employed to illustrate the theory. The results indicate that this method is more robust than other methods when the frequency response measurements are contaminated with noise.
A Holographic and BEM/FEM Analysis of a Fluid-Loaded Propeller
Authors: Rice John M. , Fennell William G. 
Published: March 2021

Abstract
The modal dynamic characteristics of an underwater propeller are investigated using a coupling of the Finite Element Method (FEM) to model the propeller and the Boundary Element Method (BEM) to model the fluid. Results of this numerical model are presented for a fluid-loaded propeller and are compared with experimental holographic results.
The FEM is known to yield very reliable solutions in the analysis of the modal dynamic characteristics of solid structures such as a propeller and the BEM is very attractive in dealing with infinite domain problems and the radiation condition, such as the infinite fluid field. Combining the two methods exploits the best attributes of both. The fluid/structural coupling is achieved by discretizing Kirchhoff’s integral with boundary elements and isolating the effective mass of the fluid. This effective mass is in the form of a mass matrix which is coupled by the degrees of freedom of the propeller. The effective mass is then input into a finite element program in the form of user elements along with the propeller’s geometry, material properties, and boundary conditions to simulate an underwater propeller in a hub.
An experiment using time averaged holographic interferometry was performed to identify the resonant modes of the propeller, identical in geometry to that used in the FEM model. In order to simulate the boundary conditions of the model the propeller was rigidly clamped in a vise at it’s root and submerged in water. Excitation of the propeller was provided by means of a mechanical shaker mounted to the vise.
Both the resonant frequencies and their respective mode shapes agreed favorably with numerical predictions.
Experimental Characterization of a Flexible Two-Link Manipulator Arm
Authors: Mayes Randall L. , Eisler G. Richard 
Published: March 2021

Abstract
Experiments were performed to verify the analytical models for a robotic manipulator with two flexible links. A finite element model (FEM) employing two-dimensional beam elements was used to model the structure. A proportional model relating input voltage to output torque was used for both hub and elbow joint motors. With some minor adjustments to the link stiffness, the FEM modal frequencies matched the experimentally extracted frequencies within 1.5%. However the voltage-torque relationship for the hub motor was found to exhibit dynamics in the frequency range of interest.
Linearization of Multibody Dynamic Systems Using Automatic Differentiation (AD) Tools
Authors: Lin Tsung-Chieh 
Published: March 2021

Abstract
This paper presents an automatic method to linearize the dynamics of multibody systems that are modeled through a recursive approach. The first-order approximation of the nonlinear dynamic systems is obtained by the use of an automatic differentiation (AD) tool (GRESS) and a 9,700 lines Fortran model for the dynamics. The efficiency and accuracy of this AD implementation is shown by two examples: a five-bar closed-chain robot manipulator and a 18 degrees of freedom tractor-trailer. This study successfully demonstrates how to create a general-purpose numerical tool that can provide accurate solutions and derivatives for multibody dynamic systems.
A Form Verification System for the Conceptual Design of Complex Mechanical Systems
Authors: Colton Jonathan S. , Ouellette Mark P. 
Published: March 2021

Abstract
This paper presents a summary of research into the development and implementation of a domain independent, computer-based model for the conceptual design of complex mechanical systems (Ouellette, 1992). The creation of such a design model includes the integration of four major concepts: (1) The use of a graphical display for visualizing the conceptual design attributes; (2) The proper representation of the complex data and diverse knowledge required to design the system; (3) The integration of quality design methods into the conceptual design; and (4) The modeling of the conceptual design process as a mapping between functions and forms.
Using the design of an automobile as a case study, a design environment was created which consisted of a distributed problem solving paradigm and a parametric graphical display. The requirements of the design problem with respect to data representation and design processing were evaluated and a process model was specified. The resulting vehicle design system consists of a tight integration between a blackboard system and a parametric design system. The completed system allows a designer to view graphical representations of the candidate conceptual designs that the blackboard system generates.
A Parametric and Experimental Study of a Power Construction Tool
Authors: Marinkovich Dragomir C. , Kremer John M. , Shabana A. A. 
Published: March 2021

Abstract
Power tools play a large role in the construction industry. From power nailers to circular saws, these tools provide an enormous and relatively untapped opportunity in the field of dynamic analysis. The intent of this paper is to analyze a unique power construction tool and then develop a computer model to simulate its dynamics. The study model used in this investigation is a nailer which utilizes a linear internal combustion engine to drive nails into wood and is completely cordless and portable. Analytical expressions for the forces acting on the system are developed and the obtained analytical results are verified experimentally. The computer model is then used to parametrically study the performance of this nailer under varying conditions. The parameters varied are the piston mass, by choosing materials with different densities, and the bumper material on which the piston impacts, to vary the coefficient of restitution between the bumper and piston. The jump discontinuity in the system velocities is predicted using a momentum balance and the restitution conditions. The coefficient of restitutions used in this study are determined experimentally using a simple impact test. It is found that there is an ideal piston mass that will provide the highest kinetic energy at the end of the stroke. It is also shown that the lower the coefficient of restitution between the piston and bumper, the lower the piston rebound height and velocity. The material chosen as having the lowest coefficient of restitution was not acceptable as an alternative material due to its low durometer, or hardness. In addition, the high elastic-energy-absorption capacity of this material may also result in increased heating of the bumper resulting in premature failure.
Suspension Design Optimization of a Washing Machine: Part II — Formulation and Implementation of Parametric Optimization
Authors: Kiray B. , Türkay O. S. , Tuğcu A. K. , Sümer I. T. 
Published: March 2021

Abstract
This paper presents an optimization methodology for determining the optimal suspension characteristics of an automatic washing machine.
Earlier publications by the authors have presented the modeling and experimental validation of the suspension dynamics of a horizontal-axis washing machine. That machine was characterized by the horizontal tub being suspended by three springs and supported by two dry-friction absorbers. A companion paper (Part I) assessed the modeling and validation of a different washing machine where the horizontal tub stands on four shock absorbers.
In this paper (Part II) various formulations for the optimization of the suspension system introduced in Part I are described and implemented by using a parametric grid optimization method. The primary objective of this effort is to determine the most suitable criteria that will be employed for future washing machine design optimization with different configurations. It is concluded that a weighted multiobjective function subject to washing machine cabinet motion constraint is appropriate for this purpose.
Future work will be toward the employment of an analytical optimization methodology in order to develop a complete design software that will be used by washing machine suspension design engineers.
Design of Smart Metal-Ceramic Composite Actuators for Macro-Motion Applications
Authors: Thirupathi Sridhar R. , Naganathan Nagi G. 
Published: March 2021

Abstract
Piezoceramic, electrostrictive, and magnetostrictive materials are being increasingly applied in active vibration control and are being investigated for other motion control and damage mitigation applications. Typically, motion ranges required in active vibration control are of the order of a few microns. On the other hand, many mechanical and electromechanical motion control applications require the point of application of the load to move through at least a few millimeters. In this research, a smart ceramic-elastic composite actuator is invented for such motion control applications. The work presented in this paper includes the concept, its illustration, development of a design geometry based on this concept, and its finite element analysis and results. It will be shown that by a proper synthesis of smart structure, a class of such actuators can be successfully designed and realized in practice.
Issues in Computer-Aided Process Planning for Parallel Machine Tools
Authors: Yip-Hoi Derek , Dutta Debasish 
Published: March 2021

Abstract
Parallel machines represent a new generation of machine tool. Through reducing the number of setups both the efficiency and the accuracy of the machining process is increased within the part domain. While Flexible Manufacturing Systems (FMSs) and Machining Cells (MCs) are said to be agile, the parallel machine is the first stand-alone machine which can claim to have this property. This makes them ideally suited for machining small batch sizes and for rapid prototyping. Unfortunately like FMSs and MCs these machines will be largely underutilized if agile data generation, processing and transfer mechanisms are not incorporated into CAD/CAM systems. One major hurdle to achieving this objective is the development of an automatic process planning system for parallel machines. This presents new challenges beyond those encountered in process planning for sequential machining. In this paper we discuss two aspects of parallel machines which impact on process planning. These are (1) the part domain for parallel machines and (2) the machine configuration.
Automation of Transient Flight Loads Estimation for Spacecraft Design
Authors: Kodiyalam Srinivas 
Published: March 2021

Abstract
Quick and effective estimation of transient dynamic flight loads is a critical part of the spacecraft design process. In this work, a transient base drive procedure is used to estimate the flight loads on a spacecraft, during the spacecraft design iterations. In this base drive procedure, only the spacecraft dynamic model is used as against a coupled spacecraft-launch vehicle dynamic model. The well established fixed interface modal model representation, with a determinate interface, is used for the spacecraft substructure. The second part of this paper is on a new, constrained optimization based procedure for notching the qualification level sine vibration loads, specified by the launch vehicle organization. Finally, the base drive and the sine vibration notch procedures are demonstrated on a spacecraft stick model and a spacecraft structure with solar arrays.
A Model for Performance-Intelligent Design Advisors
Authors: Reed R. Grant , Sturges Robert H. 
Published: March 2021

Abstract
We consider a design advisor to be performance-intelligent when its suggestions do not conflict with high level performance-related goals of the design under study. We address the problem of representing non-domain-specific design Information at a high level and describe coupling it to the inputs and outputs of design critics and their suggestion mechanisms. High level design Information represented in a function-based structure with linked allocations is shown to interact with a domain-specific design critic in three instances, viz.: allocation refinement, goal matching with a supported function, and performance-intelligent tradeoffs. Examples of manual and computer-based procedures are discussed.
Data-Conditioning in the Optimization of Function-Generating Linkages
Authors: Liu Zheng , Angeles Jorge 
Published: March 2021

Abstract
Rank-deficiencies and ill-conditioning of the synthesis matrix in the optimization of function-generating linkages are often caused by an improper selection of the input-output data points given by the {ψi,ϕi}1m pairs, where ψ and ϕ denote the input and output values, respectively. Ten basic cases of rank-deficiencies in the synthesis matrix are discussed in this paper, the associated curves, termed singularity curves, being plotted in the ψ-ϕ plane. Measures to remedy the ill-conditioning that arises in the optimization procedure and means to find the best-conditioned synthesis matrices by minimizing their condition number are also proposed.
A Stochastic Methodology for the Optimal Analytical Synthesis of Planar Mechanisms
Authors: Ogot Madara M. , Alag Satnam 
Published: March 2021

Abstract
This paper presents a stochastic based methodology for the optimal synthesis of planar mechanisms. The approach is fully automated, relatively simple to use and flexible. The methodology employs an analytical synthesis approach based on the complex number theory, to synthesize the desired mechanism based on a relatively small number of prescribed positions (hard precision points – satisfied exactly). The quality of the synthesized mechanism is then optimized at an arbitrary number of prescribed positions (soft precision points – approximately satisfied). In this manner, the number of design variables is kept relatively low without compromising on the quality of the final solution. A ‘global’ stochastic optimization approach is employed to assign values to the free choices in the analytical synthesis portion, thereby effectively guiding the design process through the often highly non-linear design space. Thus the problems associated with local minima are addressed and automation is achieved. In addition, this work investigates the feasibility of considering some of the hard precision points as design variables (variable hard precision points).
APPréCIE: A Computer Package for the Simulation and Design of Mechanical Grippers
Authors: Gosselin Clément M. , Lemieux Sylvain 
Published: March 2021

Abstract
This paper presents a simulation package developed for the computer-aided design of simple mechanical grippers. The program includes a relatively large database of gripper architectures which can be accessed interactively by the designer. The kinematic analysis of each of the generic architectures has been performed symbolically at the programming stage and explicit expressions of the input-output equations as well as the velocity relationships have been coded. This provides an accurate and fast interactive response. The kinematic dexterity and the gripping index can be plotted and are updated automatically when dimensional changes are made. Finally, a graphic animation of the grippers is available. An example is given here to illustrate the application of the design package to a practical problem. This CAD tool could be of great help in the context of the design of mechanical grippers which is one of the key challenges in advanced robotic applications.
Multilevel Parallelization Concepts for Structural Optimization Using Transputer Systems
Authors: Hartmann Dietrich , Leimbach Karl R. 
Published: March 2021

Abstract
Multilevel parallelization concepts for structural optimization provide potential to significantly improve the productivity in CAE. In particular, if large scale structural systems are to be designed with respect to a specified optimization criterion subject to a large set of constraints substantial speedup factors are achievable. This contribution is discussing generic as well as specific parallelization concepts of large structural optimization problems. Based upon these concepts transputer systems are applied as a platform for the transition from concepts to actual computer implementation.